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Quality Base Material Produced Using Full Depth Reclamation on Existing Asphalt

Pavement Structure

FHWA Contract No. DTFH61-06-R-00031

Task 2 Completion Report:

State Specifications and Construction Experiences

(Oct. 1, 2006 – June 30, 2007)

Submitted to

Federal Highway Administration

By

Nicole Nielsen, Benjamin Hauser, Terje Preber, Peter Sebaaly, Dan Johnston, Dave Huft, Sangchul Bang, Lance Roberts

South Dakota School of Mines and Technology South Dakota Department of Transportation

June 30, 2007

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Table of Contents This page was intentionally left blank. ............................................................................. 3 Executive Summary ........................................................................................................ 4 1.0 INTRODUCTION ....................................................................................................... 5 2.0 SURVEY RESULTS .................................................................................................. 5

2.1 FHWA Survey Results ........................................................................................... 5 2.2 SDDOT Survey Results ......................................................................................... 6

3.0 STATE SPECIFICATIONS ...................................................................................... 11 3.1 Material Specifications ......................................................................................... 12

3.1.1 Additive Specifications .................................................................................. 12 3.2 Construction Specifications ................................................................................. 17

3.2.1 Gradation ...................................................................................................... 17 3.2.2 Moisture Content ........................................................................................... 18 3.2.3 Density .......................................................................................................... 19 3.2.4 Compaction ................................................................................................... 20 3.2.5 Additive Mixing .............................................................................................. 21 3.2.6 Equipment ..................................................................................................... 23 3.2.7 Preparation of Roadbed ................................................................................ 26 3.2.8 Reclaiming Operations .................................................................................. 26 3.2.9 Grade ............................................................................................................ 27 3.2.10 Weather....................................................................................................... 28

3.3 Testing Specifications .......................................................................................... 29 3.3.1 Control Strips/Test Sections .......................................................................... 29

3.4 Methods of Payment/Measurement ..................................................................... 30 4.0 REFERENCES ........................................................................................................ 31 5.0 ACKNOWLEDGEMENTS ....................................................................................... 31 Appendix A .................................................................................................................... 33 Appendix B .................................................................................................................... 34 Appendix C .................................................................................................................... 37 Appendix D .................................................................................................................... 44 Appendix E .................................................................................................................... 66

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Executive Summary This report includes a summary of a survey sent out by the Federal Highway Administration (FHWA), which asks questions to determine the extent of the use of Full Depth Reclamation (FDR) throughout the country and the Canadian provinces. The results from a second, more comprehensive survey sent out by the South Dakota Department of Transportation are also summarized. This summary provides additional details of FDR such as; when each state began the use of FDR and for how long, each state’s specifications, selection criteria, types of stabilization admixtures, and types of problems, if any, each agency has experienced with FDR. The second part of this report is a summary of FDR specifications for thirteen states and one Canadian province. The specifications are broken up into material specifications, construction specifications, and testing specifications. The material specifications include six stabilizing materials. The stabilizing materials included; cement, lime, fly ash, foamed asphalt, bitumen, and virgin aggregate. Construction specifications included; gradation, moisture content, density, compaction, additive mixing, equipment, roadbed preparation, reclaiming operations, grade, and weather considerations. The testing section details the Quality Control/Quality Assurance (QC/QA) procedure, control strips, and test pits. Methods used for measurement and payment of materials are also discussed.

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1.0 INTRODUCTION

A preliminary survey to determine the extent of FDR usage around the country

was conducted through FHWA Divisions Engineers in December of 2006. The survey

questionnaire was prepared by Jason Harrington, FHWA’s Contracting Officer’s

Technical Representative (COTR) for this project. A summary of these results is

reported in Section 2.

In February of 2007, the South Dakota Department of Transportation (SDDOT)

distributed an in-depth survey to 50 states, 10 Canadian provinces, and numerous local

government agencies with the intent of determining the extent of the use and knowledge

of FDR. A total of 118 agencies responded. Of these 118 responses, 23 State

Departments of Transportation (DOT) responded that they have specifications for FDR.

Section 2 of this report summarizes the results of these surveys. The results of the

state specifications, including: additive types, density, moisture content, and equipment

requirements, are summarized in Section 3.

2.0 SURVEY RESULTS

2.1 FHWA Survey Results

The preliminary survey sent out by FHWA was utilized to determine the extent of

the use of FDR throughout the country. Original questions and results can be found in

Appendix A.

There were 19 total responses to the FHWA survey; 17 state responses, the

commonwealth of Puerto Rico, and FHWA Federal Lands Highway. The results varied

from extensive experience/knowledge to very little experience/knowledge of FDR. The

first question asked was if FDR is currently being used and if so, to what extent. Ten

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respondents indicated they currently use FDR, seven responded that they have never

used FDR and two responded as maybe. Nine out of the ten respondents that indicated

they are currently using FDR were state DOTs.

Of the respondents that currently use FDR, the extent of the usage varied from

very little knowledge/experience to extensive experience. Two states indicated that

they have used FDR in the past but are not currently using the process. They gave no

reasons for the discontinued use. Federal Lands Highway reported extensive

employment of FDR and will continue its usage for the foreseeable future. Puerto Rico

reported that it has never used FDR. Nine states indicated that either city or county

agencies within their state have used FDR. Two states reported that FDR was not used

at the local level while six reported that they did not know. Some states indicated that

recent increases in asphalt binder and aggregates prices might increase their interest in

the FDR process.

2.2 SDDOT Survey Results

The SDDOT conducted a comprehensive survey that was sent out to all 50

states, 10 Canadian provinces, and numerous local governments to determine the

experiences that each agency has had with FDR. The 118 responses included:

• 34 State DOT’s

• 5 Canadian Provinces

• 65 County highway departments

• 14 other agencies (cities, townships, etc.)

Figure 1 is a map of the state DOT’s responding to the survey. The responding states

are in white. Local governments from other states also responded.

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Figure 1. States in white responded to the SDDOT survey.

A total of 66 agencies responded that they did have specifications for FDR, 23 of

these responses were from state DOT’s. Four Canadian provinces also indicated that

they have specifications. The six types of specifications listed in the survey were:

• Material components

• Gradations

• Mix designs

• Field testing and quality control

• Lab testing

• Structural design (i.e. removal depth, in situ undisturbed material, FDR

thickness, stabilization type, surfacing type and thickness)

Most states had a combination of the above specifications. Gradation

specifications were the most common, with 51 agencies having such requirements.

Field testing/quality control specifications were used by 43 agencies. Results for

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agencies reporting established specifications for the remaining four specification types

are as follows: material components – 41, mix design – 35, laboratory tests – 33, and

structural design – 27. Figure 2 is a visualization of these results which were used to

narrow down the search for state specifications. A summary table of specifications from

each agency can be seen in Appendix B.

0 10 20 30 40 50 60

Number of Agencies

Other

None

Field Tests/QC

Lab Tests

Structural Design

Mix Design

Gradation

Components

Figure 2. FDR specifications indicated as being used by the various agencies.

Of the 118 agencies that responded to the survey, 83 continue the use of FDR,

31 have never used FDR, and 4 have discontinued the used of FDR. Of the 31

respondents that have never used FDR, the reasons included; lack of familiarity, lack of

contractor experience, lack of specifications and lack of appropriate sites as shown in

Figure 3. Four agencies that discontinued the use of FDR cited the lack of appropriate

sites as the main reason. Only two agencies reported discontinued use due to

unacceptable performance or difficulty in achieving compaction.

9

0 5 10 15 20

Number of Agencies

Other

Cost

Others' Performance

Lack of Specifications

Lack of Contractors

Lack of Familiarity

No Appropriates Sites

Figure 3. Reasons why agencies indicated they have never used FDR.

Figure 4 shows the history of FDR use going back to 1970, as the earliest application.

The current highway condition and the existing subgrade and base conditions were

reported as the main selection criteria.

The types of stabilization and percentages of agencies indicating their

experience with included:

• Bituminous stabilization (emulsions or foamed asphalt) – 71% • Mechanical stabilization (virgin aggregate or recycled asphalt pavement) –

65% • Chemical stabilization (cement, fly ash, or lime) – 34%

Several agencies had experience with more than one type of stabilization

technique. Also, 61% of respondents reported that FDR performed about the same as

conventionally constructed pavements (i.e. new grade, new base and surfacing). The

common distress types reported are:

• Reflective cracking • Block cracking • Stripping

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• Load cracking • Transverse cracking • Rutting

1960

1965

1970

1975

1980

19851990

1995

2000

2005

1 3 5 7 9 11 13 15 17 19 21 23 25

Number of Agencies

Yea

r Ag

enci

es S

tart

ed U

sing

FDR

Figure 4. The history of FDR usage by the various agencies.

Figure 5 shows a summary of the types of distresses that have been

encountered on FDR projects.

The majority of agencies reported that they have plans to use FDR for low and

high volume highways and 78% of 81 agencies plan on using FDR at approximately the

same rate as they are currently using it. Original survey questions and answers can be

found in Appendix C.

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Figure 5. Number of states reporting various problems related to FDR usage.

3.0 STATE SPECIFICATIONS

This section of the report focuses on thirteen state DOT’s and one Canadian

province which have specifications for FDR and have shared them with the research

team. Since most counties operate off of state specifications, state specifications and

Canadian provinces were the only groups researched. In-place asphalt recycling is

referred to by many different names by various agencies. Some of these common

names include: Process In-Place Surfacing, Full Depth Recycled Pavement, Reclaimed

Base Course, Recycled Base, Processed Pulverized Surfacing, and Full Depth

Reclamation. Although this type of in-place asphalt recycling goes by a variety of

names, the general idea is that the existing hot-mix asphalt (HMA) surface and a

predetermined amount (depth) of the base and/or subbase are pulverized into a

homogenous mass. In some cases, additives are included. After this mass is

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thoroughly blended, the mixture is placed, shaped and compacted to the depths, grades

and dimensions shown on the plans.

Specifications can fall into one of three categories: material specifications,

construction specifications, and testing specifications. A table of these specifications

can be found in Appendix D. The Portland Cement Association also has recommended

construction specifications for FDR stabilized with cement. These specifications are in

Appendix E.

3.1 Material Specifications

Material specifications include requirements for the stabilization additives,

crusher dust, curing seal, virgin aggregate, and water.

3.1.1 Additive Specifications

Additives include: portland cement, fly ash, lime, cutback bitumen, emulsions,

foamed asphalt, glass cullet, synthetic fibers, and additional aggregate.

Four agencies require that the portland cement be Type I or II, meeting the

requirements of AASHTO M85, which requires coarser cement. This type of cement

results in higher ultimate strengths and lower early-strength gain. The AASHTO M85

covers the physical and chemical test requirements for portland cement Types I-V. The

physical tests include; “Standard Test Method for Air Content of Hydraulic Cement

Mortar” (ASTM C 185), “Standard Test Method for Autoclave Expansion of Hydraulic

Cement” (ASTM C 151), “Standard Test Method for Time of Setting of Hydraulic

Cement by Vicat Needle” (ASTM C 191), “Standard Test Method for Fineness of

Hydraulic Cement by Air Permeability Apparatus” (ASTM C 204), and “Standard Test

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Method for Compressive Strength of Hydraulic Cement Mortars” (ASTM C 109).

Chemical tests include; oxide analysis by X-ray Fluorescence (XRF), loss on ignition,

insoluble residue, and calculated total alkalis. Another specification typically used for

portland cement requirement is ASTM C-150. Additional requirements contained in

AASHTO M85 but not in ASTM C-150 are; a maximum fineness limit for Type I, II, IV,

and V, a maximum tricalcium silicate of 58% for Type II, a minimum silicon dioxide limit

of 20% for Type II, and a maximum processing additions limit of 1% for all types of

portland cement (1).

The specifications for fly ash as required by two states include: Fly ash is

required to be Class CS or FS, as shown in the plans. Another state has chemical and

physical requirements for fly ash. These additional requirements can be seen in Table

1 below.

Table 1. Chemical and physical requirements for Class CS and Class FS fly ash (4)

Supplementary Specification Requirements

Chemical Requirements Class

CS Class

FS Calcium oxide (CaO) content, minimum, % 22.0 na Calcium oxide (CaO) variation in percentage points of CaO from the average of the last 10 samples (or less provided 10 have not been sampled) must not exceed ± 5.0 5.0 Silicon dioxide (SiO2) plus aluminum oxide (Al2O3) content, minimum, % na 75.0 Variation in percentage points of SiO2+Al2O3 fron the average of the last 10 samples (or less provided 10 have not been tested) must not exceed ± 8.0 8.0 Sulfur trioxide (SO3) content, maximum, % 8.0 8.0 Moisture content, maximum, % 3.0 3.0 Loss on ignition, maximum, % 6.0 6.0

Physical Requirements Class

CS Class

FS Strength activity index, 7-day or 28-day, minimum, % of control 75 75 Water requirements, maximum, % of control 105 105 Autoclave expansion or contraction, maximum, % 0.8 0.8 Fineness, Amount retained when wet-sieved on 45-µm sieve, maximum, % 34 34 Percent retained on 45-µm (No. 325), max variation, percentage points from average 5 5 Density, max variation from average, % 5 5

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Several agencies have requirements for lime, limestone, or hydrated lime. One

state requires that any lime for soil stabilization shall meet the requirements of AASHTO

M 216 (“Standard Specification for Lime for Soil Stabilization”). Another state has

chemical and physical requirements for hydrated lime, lime slurry, and quicklime. The

chemical requirements are listed in Table 2. The only physical requirements are wet

and dry sieve requirements.

Table 2. Chemical requirements for lime products (4)

In the case of bituminous stabilized FDR, one agency specifies the use of

cutbacks and one agency specifies the use of emulsions or foamed asphalt. Cutbacks

are formed when the asphalt is mixed with petroleum solvents. Cutbacks are added to

help the bitumen penetrate the road surface and adhere to cover aggregate. Cutback

bitumen involves adding 0 – 8% cutting agent (typically lighting kerosene) in

combination with minor amounts of diesel fuel or anti-stripping agent (3). This

technology allows the asphalt to be mixed at much lower temperatures. The province of

Saskatchewan specifies a minimum cutback bitumen content of 1.5% by dry weight of

aggregate and application temperatures as shown in Table 3 below. Several states

now have environmental regulations which no longer allow for cutback bitumen to be

used.

Specification Requirements

Chemical Requirements Hydrated

Lime Commercial Lime Slurry Quicklime

Total "active" lime content, % by wt 90.0 Min 87.0 Min Unhydrated lime content, % by wt CaO 5.0 Max 87.0 Min "Free Water" content, % by wt H2O 5.0 Max

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Table 3. Specified temperature limits

for type of bituminous binder (2).

Type of Bituminous Binder Temperature, C° (F°) Cutback Asphalts RC - 30, MC - 30 30 – 55 (86 – 131) RC - 70, MC - 70 60 – 80 (140 – 176)

RC - 250, MC - 250 75 – 95 (167 – 203)

When using emulsified asphalt, it shall be type CSS-1 and it must be applied at a

rate that will leave a residual asphalt content of 3.0% based upon dry weight of

aggregate, or as determined by the mix design process. The emulsified asphalt CSS-1

must meet AASHTO M 208 (“Standard Specification for Cationic Emulsified Asphalt”)

requirements. CSS-1 is a slow-setting cationic emulsion which is easy to use without

dilution. This state also requires that the absolute viscosity of the emulsified asphalt

shall be between 600 poises (60 Pahs) and 1,200 poises (120 Pahs).

Two different requirements for foamed asphalt were found. The first requires that

when using foamed asphalt, the asphalt binder shall meet the requirements of AASHTO

M 320 (“Specification for Performance-Grade Asphalt Binders”) and shall maintain a

temperature within ±20°F (10°C) of the optimum temperature, as established by the mix

design. Foamed asphalt is a mixture of air, small amounts of cold water and hot

asphalt. When the cold water is mixed with the hot asphalt binder the asphalt expands.

This expansion creates a brief, high volume, asphalt foam until the binder resumes its

original properties. The foaming characteristics may be verified by measuring a sample

from the equipment’s test nozzle.

Another agency requires that the foamed asphalt has a maximum aggregate size

of 2 inches (50 mm) and meet the design parameters in Table 4.

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Table 4. Foamed Asphalt Stabilized Base Course Mix Requirements.

Design Parameters Value Marshall Compacted Specimen, AASHTO T 245 (1) Compaction, number of blows 75 Indirect Tensile Strength, AASHTO T 283 (1) Tensile Strength Wet, min. kPa (2) Tensile Strength Ratio (TSR), min. %

350 70

Foamed Asphalt Expansion Characteristics @ 160, 170, & 180°C (1) Half-Life of Foamed Expansion, min, sec. (2) Expansion Ratio, min.

12 15

(1) Total time for foamed asphalt to settle to half of the maximum foamed volume. (2) Maximum foamed asphalt volume divided by non-foamed asphalt volume. (3) Graph half-life to expansion ratio for the three temperatures and percentage of water

(1-5%) to determine the minimum foamed asphalt characteristics.

Other materials have minimum requirements. Some of these requirements

include:

• Glass cullet must meet AASHTO M 318 (“Standard Specification for Glass

Cullet Use for Soil-Aggregate Base Course”) requirements. This

specification is used in conjunction with AASHTO M 147 (“Standard

Specification for Materials for Aggregate and Soil-Aggregate Subbase,

Base, and Surface Courses”) for processed glass cullet intended for use

as a granular road base material. Glass cullet has proven to provide

adequate stability and load support for use as road or highway bases

when properly processed and compacted to an appropriate density.

• Curing seal must be a cutback Type MC-70 or MC-250.

• Blotter sand and crusher dust had only gradation requirements.

The main specification for virgin aggregate and recycled material is gradation

requirements. Recycled material which contains vegetation, winter sand, granular fill or

construction debris must be removed.

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Several agencies have a special requirement for water. In general, the water

must be clean and free from harmful concentrations of acids, alkalis, oil, salt, industrial

wastes, or other organic or chemical substances. Other requirements include: the total

amount of inorganic solids shall not exceed 0.20%, and extraneous material should be

screened out when pumping from streams, ponds, or lakes. When using portland

cement as a stabilization additive, the water must meet AASHTO T 26 (“Standard

Method of Test for Quality of Water to Be Used in Concrete”). This specification

determines the acidity or alkalinity in water to be used in concrete.

3.2 Construction Specifications

Construction specifications can be grouped into several areas that include:

gradation, moisture content, density, compaction, additive mixing, equipment, roadbed

preparation, reclaiming operations, grade, and weather considerations.

3.2.1 Gradation

Gradation is the most common construction specification. Almost every agency

included in this report has gradation control requirements. The gradation requirements

vary between 100% passing the 1.5 inch (38 mm) sieve to 100% passing the 3.5 inch

(127 mm) sieve.

Lime-treated bases, cement-treated bases, and bitumen-treated bases are the

only stabilized FDR found that had gradation specifications. When using bitumen, the

gradation can vary with more fines for foamed asphalt than for asphalt emulsion. A

summary of the gradations specifications are shown in Table 4. Gradation

specifications for lime/cement treated bases are similar to those of the base course.

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There are no specific gradation requirements for foam treated bases or asphalt

emulsion treated bases.

Most agencies also require that the recycled asphalt and granular material be

processed such that a uniform blend is obtained. In many cases, the actual gradation

must be determined by the Engineer from a control strip or test pit. The materials shall

also be processed and hauled in a manner that avoids contamination and loss.

Table 5. Typical gradation specifications for stabilized FDR.

Agency Gradation Requirements % Material Passing

Agency 3 inch

(76 mm) 2 inch

(51 mm) 1.5 inch (38 mm)

3/4 inch (19 mm)

No. 4 (4.75 mm)

Lime 100 60 Cement 95 55 Bitumen 100 80-100 55-90 40-70

3.2.2 Moisture Content

Several states have specifications for the moisture content of the recycled

material, but these requirements are very diverse. In general, the moisture content of

existing pavement and underlying material must be uniform for the full depth and extent

of each layer. Additional water may need to be added to facilitate uniform mixing and to

achieve a stable reclaimed layer above the minimum specified density. A few states

require AASHTO T-180 (“Standard Method of Test for Moisture-Density Relations of

Soils Using a 10 lb (4.54 kg) Rammer and an 18 inch (457 mm) Drop”) for determining

the relationship between the moisture content and density of soils when compacted.

When using unstabilized bases the optimum moisture content shall be within 2% of

optimum or no greater than 5% by weight when it leaves the pugmill.

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When using lime or cement the optimum moisture content should be determined

through a mix design. Water shall then be added, if necessary, to bring the mixture

within 100 to 120% of optimum before the lime or cement is spread. If the road is

already above optimum moisture content, each layer shall be aerated until optimum

moisture content is achieved.

When using emulsion, one agency requires that the aggregate moisture content

can be a maximum of 2.5%, prior to the addition of emulsion. After the addition of the

emulsion, the material shall be aerated until a moisture content of 5% or less has been

achieved. Another agency requires that for each project the Engineer shall determine

the moisture content independently, with 2.5% as minimum moisture content.

3.2.3 Density

Density specifications are also common requirements. There are a variety of

ways that each agency determines the optimal density. One state requires that the

surface be watered and rolled until the density is not increased by more than 1% from

the previous roller pass. Another agency requires that nuclear gauge moisture and

density tests be performed every 500 feet (152 meters) to assure consistent and

accurate densities throughout the section. When using nuclear gauge measurements,

the gauge needs to be calibrated either by Reference Calibration Blocks or a second

form of density testing, such as: ASTM D1557 (“Standard Test Method for Density and

Unit Weight of Soil in Place by the Sand-Cone Method”) or ASTM D2167 (“Standard

Test Method for Density and Unit Weigh of Soil in Place by the Rubber Balloon

Method”).

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The most common requirement is that the base course must be at least 95% of

the maximum dry density and the HMA layers must achieve a 98% maximum dry

density as determined by a control section, AASHTO T-180D, or a nuclear density

gauge supplied by the owner agency. Some of the requirements for density are as low

as a minimum of 92% of the laboratory design. It should be noted that unless otherwise

specified these densities are for the entire depth of the pavement. Material non-

uniformity is likely to occur, therefore, density testing should be done throughout the

entire FDR process.

The lime-treated FDR layer shall be compacted until the entire depth of the

mixture is at least 98% of the maximum dry density. Cement-treated layers shall be

compacted until the mixture is at least 95% of the maximum dry density. Fly ash and

bituminous-treated layers shall be compacted to 97% of the modified Proctor dry

density. Some states use the density to establish a rolling pattern for compaction.

3.2.4 Compaction

Every agency responding has requirements for compaction methods or

compaction equipment. Most require that the material be rolled with a vibratory

pad/tamping foot roller, a vibratory steel drum soil compactor or a Type II pneumatic

roller. A sheep's foot roller or steel wheel roller is typically used for the initial

compaction and a pneumatic-tired roller is typically used to roll the finishing surface.

Compaction is usually done until the optimum density is obtained.

General compaction requirements include:

• Rolling shall begin at the sides and proceed towards the center. • Proof rolling shall consist of a minimum of four passes, two each lane; one

pass at edge of pavement and one adjacent to the pavement centerline.

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• If multiple passes are used, a minimum of a six inch (152 mm) overlap shall be required.

• The final rolling of the top surface of the granular material shall embed as many loose stones as possible, the finished surface shall be smooth and free from waves and inequalities.

• After compaction, the roadway surface shall be treated with a light application of water and rolled with pneumatic-tired rollers.

The only compaction requirement (other than density requirements) for additive

stabilized bases is that the compaction be completed within a certain period of time,

such as:

• When using fly ash stabilization, all compaction must be completed within 6 hours of fly ash application.

• When using cement stabilization, compaction must begin within 45 minutes from the time water is added to the cement mixture and must be completed within 2 hours.

• When performing unstabilized FDR, the initial rolling shall be continued through the next two calendar days till the target density is achieved.

3.2.5 Additive Mixing

Most DOT’s provide the mix design to the contractor. This mix design typically

includes: percent of stabilizing additive, percent of water, optimum moisture content,

and amount of additional virgin aggregate. In each case, the final mixture shall be a

homogenous mass. Most agencies do not have specific requirements for the mixing of

additives because there has not been enough research in this area. Some agencies

also determine the amount and rate of additive application by a control strip or a test pit.

Control strips and test pits are discussed in further detail in section 3.3.1.

When constructing cement stabilized base, mixing should continue until a

homogenous and uniform material is produced. One agency requires that, when using

cement, it must be added using a calibrated meter at a rate of 2% by dry weight of

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aggregate. Only spreading and mixing equipment should be allowed to pass over the

spread cement to avoid rutting.

When constructing a lime stabilized base, the lime should first be spread and

then mixed with the base. Mixing should continue until a homogenous and uniform

material is produced. One agency requires that the lime mixture be allowed to mellow

for 1 to 4 days. Another agency requires that the mixture be allowed to mellow till it

forms a loam consistency. The mixture is then spread a second time if necessary.

When using quicklime, additional water should be blended with the mixture (even if the

material is already at the optimum moisture content) so that the chemical reaction

between the quicklime and the water is maintained. When creating a lime and fly ash

stabilized base, the fly ash application shall begin within 4 days after the lime mixing

operation has been completed.

Hydrated lime can be applied dry on wet aggregate or as slurry. Dry hydrated

lime on wet aggregate may be applied through bags. Lime slurry is placed by uniformly

distributing the slurry in successive passes over the roadway until the specified lime

content is reached.

Fly ash shall be uniformly dry mixed using approved equipment until a loose,

homogeneous mixture is obtained. Care shall be taken to avoid the formation of fly ash

balls.

When creating a foamed asphalt-stabilized base the mix shall be composed of

RAP, reclaimed aggregate, new aggregate and foamed asphalt binder. If necessary,

lime, cement, and/or fly ash can be added to increase the fines content.

23

The mix design includes: (1) A minimum of 5 Marshall specimens are compacted

to 75 blows with asphalt content 0.5% apart, (2) Indirect Tensile Strength (ITS) tests are

performed using AASHTO T 283 on both dry and soaked specimens at each asphalt

content (refer to Table 4), (3) A graph of ITS values versus asphalt content for both dry

and soaked specimens is created, (4) The percentage of foamed asphalt binder to be

added is based on the total mass of the mixture.

One agency requires that the glass cullets be mixed with base course prior to

being placed on roadway. This may be done by mixing the glass cullets in with the

reclaimer or by feeding the processed FDR material into a mobile pugmill for mixing with

the glass prior to laydown.

3.2.6 Equipment

Every agency discussed in this report has specifications as to the type or

capabilities of the equipment to be used in the recycling operation. Equipment that is

used in all recycling processes include: reclaiming machines, graders, and compaction

equipment. Other equipment requirements depend on the type additives utilized.

Reclaiming Units

In practice, any type of reclaiming equipment may be used as long as it is able to

process and blend the material to the gradation requirements and blend the material

into a homogenous mass. Many agencies also require that the reclaiming unit be self-

propelled, have a positive depth control, and maintain a constant cutting depth. One

state requires that the reclaiming unit have a minimum of 600 horsepower; although

units with only 350 horsepower can successfully perform FDR when the asphalt

surfacing is thin and the depth is not too deep.

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Other requirements for the reclaiming unit include:

• Equipped with a gauge to show depth of material being processed. • Fitted with a front breaker bar to break down material into specified sizes. • A cutting width ranging between 75 – 120 inches (191 – 305 cm) and a

cutting depth of at least 10 inches (25 cm) with a single pass. • Equipped with an adjustable down position to control depth.

Some of the required capabilities include: capable of introducing water at time of

mixing, capable of removing excess fines, and capable of placing the mixture in a

spreader, windrow, truck, or hopper of a paver in one continuous operation.

Compaction Equipment

Rollers shall be a combination of pneumatic tired and steel wheel capable of

deriving the required compaction. Requirements for the compaction equipment include:

• Roller speed should be between 2 and 6 miles (3.2 and 9.7 kilometers) per hour.

• At least one vibratory roller shall be used on each reclaimed surface and shall have a compacting width of not less than 4.9 feet (1.5 meters) and have a gross mass of not less than 16 tons (14.6 metric tons).

• After compaction has been attained, the base shall be proof rolled with an 18,000 pound (8165 kg) per axle single unit vehicle to determine the areas of base or subgrade failure.

• The sheepsfoot or pad foot roller shall provide at least 50,000 lb (22,680 kg) of dynamic force and final rolling shall be accomplished using a smooth steel wheel vibratory roller of 27,000 lb (12250 kg). Material shall be rolled with a vibratory pad/tamping foot roller; final rolling shall be done using a minimum 84 inch (2.1 meter) wide single vibratory soil compactor.

• At least one vibratory roller having a compaction width of not less than 5 feet (1.5 meter) and a gross weight of not less than 10 tons (9.1 metric ton) capable of producing high amplitude and low frequency vibrations shall be used.

Mechanical Stabilization

Equipment that is specific to mechanical stabilization includes a spreading unit to

distribute the aggregate or fibers at a controlled rate. No specifications are noted for

this type of equipment.

25

Chemical Stabilization

Equipment used for chemical stabilization is similar to the spreaders used for

mechanical stabilization. Lime, cement, and fly ash can all be spread either wet or dry

and need to be distributed at a controlled rate. In addition to being spread at a

controlled rate, the slurry tanks must be equipped with agitation devices. One agency

requires that the cement must be uniformly spread by a cyclone-type spreader.

Foamed Asphalt and Asphalt Emulsion Stabilization

Several specifications are noted for foamed bituminous stabilization. The

following two paragraphs explain those specifications for foamed asphalt.

One agency requires that the reclaiming machine using foamed asphalt for

stabilizing be equipped with two microprocessor-controlled systems, two independent

pumping systems and spray bars to regulate the application of foamed bitumen

stabilizing agent. The spray bar must have individual expansion chambers into which

both hot asphalt and cold water are injected under pressure through individual orifices

that promote atomization. The spray bars must have self-cleaning nozzles. A test

nozzle must be fitted at one end of the spray bar to obtain samples for testing. An

electrical heating system must maintain the temperature of all bitumen flow components

above 300°F (150°C).

Another agency requires that when using foamed asphalt, the specified

percentage of water shall be added accurately and uniformly to the hot asphalt binder

and be fitted with a test nozzle to provide field samples. It must also be equipped with a

thermometer to measure the temperature of asphalt.

26

One agency requires that the reclaimer for asphalt emulsion have a system that

includes a full width spray bar with nozzles for adding asphalt emulsion and a positive

displacement pump interlocked to the reclaimer speed so that the amount of emulsion

added is automatically adjusted with changes in speed. The additive system shall be

capable of adding up to 7 gallons per square yard of emulsion. To minimize emulsion

overlap, individual nozzles on the spray bar should be capable of turning of

independently. The use of heating devices to soften the pavement is not permitted.

3.2.7 Preparation of Roadbed

Preparation of the roadbed before placement includes pulverization of the

existing pavement and a portion of the underlying base before mixing. All vegetation

and debris within the width of pavement to be reclaimed shall first be removed. One

agency requires that the existing pavement be swept with a power sweeper to remove

all of the undesirable material before pulverization. Prior to starting, the contractor shall

locate and protect existing drainage, utility and underlying structures. When shown on

the plans, the roadbed shall be proof-rolled before pulverizing or scarifying existing

material.

The road is prepared by loosening and pulverizing the in-place pavement

structure to the width and depth to be stabilized without damaging the underlying

materials.

3.2.8 Reclaiming Operations

There are a variety of specific requirements when it comes to the actual

reclaiming operations. In general, the materials encountered and other materials

27

designated in the contract shall be blended to provide a uniform mix of all materials

before laydown. In one case, each sequence of the reclamation process shall be a

maximum of 1 mile (1600 meters) long and shall be placed before starting the next

sequence. Some require that first a uniform layer of crusher dust shall be spread to the

full length of the roadway before new aggregate or recycled material is added.

The new base should be mixed with existing material to provide a uniform

mixture to specified depth before adding lime or fly ash. Cement, lime, and fly ash are

applied at a rate specified by the Engineer and mixed to the depth shown on the plans.

The application rate is maintained within ±10% of that specified by the Engineer.

Placement operations shall commence immediately in conjunction with

processing. One state requires that the blended materials shall be placed in lifts not

exceeding 4 inches (10 cm) in thickness.

3.2.9 Grade

About half of the agencies responding have specifications for the grade of the

roadway after the placement of the recycled base. Most require that the roadway be

rolled, compacted, shaped, and maintained to a specified tolerance of the cross-

sections and/or grades in the plans. Some require that it be within ±3/8 inch (9.5 mm)

up to 1 inch (25 mm) of the grade specified on the plans. One agency requires that

surface deviations cannot be more than ¾ inch (19 mm) in a 10 foot (3 meter) stretch.

Many agencies require that the equipment have automatic controls, so that the

transverse slope can be determined within 0.01% of specified. If any rutting, shoving,

rolling, or deflection happens which is greater than that of the specified tolerance, most

states require that the areas shall be considered for base or subgrade repair at no cost

28

to the state or that the contractor take a deduction in pay. Other requirements include:

the crown of the compacted reclaimed mat shall be within 6 inches (15 cm) of the

centerline established by the construction survey. These grades are not dependant

upon the types of stabilizing additives.

3.2.10 Weather

Nine of the thirteen states have some kind of weather requirements for

construction. Most require that the temperature be above a certain point before

construction can proceed. These temperatures vary between 40oF and 60oF (5oC and

16oC). Others impose seasonal limitations on construction. They vary between April 1st

through November 1st, April 15th through October 15th, and May 1st through September

30th, depending upon region. Other weather limitations include:

• No standing water. • Ground can not be frozen. • Existing pavement or sub-base can not contain frost or be excessively

wet.

It is also important that the weather conditions are not too windy so that lime, fly

ash and cement can be properly spread. Cement-treated material shall have sufficient

protection from freezing for seven days after its construction. In general, reclaiming

operations shall not be permitted when the weather conditions are such that proper

pulverizing, mixing, spreading, shaping, and compacting cannot be accomplished. The

moisture of the materials to be used in the mixture must meet the specified limits. If rain

increases the cement's moisture content outside the specified limits, the area affected

must be tested for unconfined compressive strength.

29

3.3 Testing Specifications

Testing specifications include QC/QA and control strips or test pits. One agency

requires that when using lime, the producer must maintain QC of the material using the

requirements below:

• Certifications on shipments of hydrated lime or quicklime must be provided to the Department, with a minimum of one test for every three truckloads with at least one test per project.

• Shipments of commercial lime slurry and carbide lime slurry should be tested a minimum of once for every 200 tons (181 metric tons).

The same agency has a similar quality monitoring program for fly ash. This

program requires that a monthly mill certificate be submitted to the Department that

shows that the fly ash complies with the specification requirements. A monthly test

report and a split sample from the same material must also be submitted.

3.3.1 Control Strips/Test Sections

Several agencies use control strips or test pits to obtain the necessary

information to make adjustments to the mix design. One agency has very specific

requirements for their control strip. The contractor shall construct a test strip at least

328 feet (100 meters) long and a full lane width. The test strip must demonstrate that

the equipment can produce recycled layers to meet requirements. The test strip also

determines the effect on the gradation of the recycled material by varying the forward

speed and determining the sequence and manner of rolling necessary to obtain the

compaction requirements. The full recycling production will not start until a passing test

strip has been accomplished.

30

Another state also requires a test section be constructed approximately 492 feet

(150 meters) long and one lane wide within the project limits. Forward speed and

processing direction will be recorded and material will be analyzed by the Engineer

before any reclaiming operations begin.

One state’s specification requires a test pit. The Department will take and

analyze test pits to the depth to be recycled. The following information is provided for

each pit: location, depth of existing HMA layer, and existing aggregate gradation. This

information is an indication of the existing conditions. Any gradation deficiencies

indicated in test pits shall be corrected by blending the appropriate aggregate sizes into

the mixture.

3.4 Methods of Payment/Measurement

Most agencies measure and pay for the full depth of recycled material (including

the foamed asphalt) by the square yard (meter). One agency specifies that the

reclaimed base course shall be measured in-place to the limits specified on the plans.

Measured materials are generally paid for at the contract unit price bid per square yard

(meter). Lime, quicklime, portland cement, and dry fly ash are measured by the ton

(metric ton). One agency requires that the bituminous material be paid at the contract

unit price per gallon (liter). Most additives are paid for by the unit bid price. Pay

deductions will apply to gradation, density, cement content, and water content over the

allowable tolerances from specifications.

Payment shall also include compensation for all labor, equipment, and materials

necessary for crushing, pulverizing, blending, spreading, shaping, grading, compacting

and all incidentals necessary to complete the work within the project.

31

Compaction will be measured for the top eight inch (20.3 cm) lift of reclaimed

material; acceptance testing will be based on a random schedule of one per 400 square

yards (one per 334 square meters).

4.0 REFERENCES

1. Concrete Producer, The. Differences in Cement Standards. Oct. 2005 <http://findarticles.com/p/articles/mi_m0NSY/is_10_23/ai_n15880274> Obtained in May 2006. 2. Saskatchewan Highways and Transportation. Specification for Bituminous Prime for Grading.<http://www.highways.gov.sk.ca/docs/reports_manuals/manuals/std_spe c_manual/4010.pdf> Obtained May in 2006. 3. Slaughter, Greg. Environmental Comparison of Cutback Bitumen and Bitumen Emulsions for Sealing Roads. Fulton Hogan Limited <www.fh.co.nz/fms/projects/Technical%20Papers/Cutback%20Versus%20Emulsi fied%20Bitumen.pdf> Obtained in July 2007 4. Texas Department of Transportation Departmental Material Specifications. DMS- 4615, Fly Ash for Soil Treatment. Aug. 2004. <ftp://ftp.dot.state.tx.us/pub/txdot- info/cst/DMS/4000_series/pdfs/4615.pdf> Obtained in May 2006.

5.0 ACKNOWLEDGEMENTS

The authors are grateful for the technical and financial supports provided by the

Federal Highway Administration. The technical program monitor is Jason Harrington,

Office of Pavement Technology. The following individuals have served as the Project

Technical Panel members and provided valuable comments, suggestions, and review.

Their contributions are greatly appreciated.

Randy Battey, Mississippi DOT

Todd Casey, Base Construction Co. (ARRA)

32

John Epps, Granite Construction, Inc.

Joe Feller, SDDOT

Gary Goff, FHWA ND Division

David Gress, Univ. of New Hampshire

Gregory Halsted, PCA (ARRA)

Brett Hestdalen, FHWA SD Division

John Huffman, Terex Roadbuilding (ARRA)

Tim Kowalski, Wirtgen America

David Lee, Univ. of Iowa

Chuck Luedders, FHWA Direct Federal Lands

Ken Skorseth, SDSU

Ken Swedeen, Dakota Asphalt Pavement Association

Todd Thomas, SemMaterials (ARRA)

Mike Voth, Central Federal Lands Division, FHWA

33

Appendix A These are the original survey questions that Jason Harrington sent to all FHWA

Divisions Engineers. 1a. Is FDR used now? 1b. If yes, what is the extent? (1 least use: 5 extensive use) 2. Has it been used in the past, but not now? 3. If you know are city/county agencies using FDR? 4. If state has experience in FDR, who would be a good contact?

The level is the amount that the state uses FDR. This was gauged by the result compiled from the comments on the survey answers and not the states themselves. Results of Preliminary Survey: State or Province 1a 1b 2 3

Contact name

Contact type

(Y/N/M) 1 to 5 (Y/N) (Y/N/Don’t

know) (St/Cnty/Cty) AZ N 1 Y D Dan Simpson ST CA Y 3 N Y Joe Peterson ST CO Y 4 N D Todd Gonser Federal Lands Highway Y 5 N N Brad Neitzke FED GA N N Y

IA Y 4 N Y Micheal Heitzman ST

IL M 1 N Y Kevin Burke ST

MD N N Y Gene Warenfeltz Cnty

MO N Y N Joe Schroer ST NC Y 3 N Y Emily McGraw ST NH Y 4 N D Alan Rawson ST

NV Y 5 N Y Sohila Bemanian ST

NY Y 1 N Y Bob Burnet ST PA Y 3 N Y Bruce Harter ST Puerto Rico N N D SC M 1 N D Stan Bland ST TN N N D Clay Cudwel ST

TX Y 4 N D Caroline Herrera ST

WV N N N

34

Appendix B

FDR Survey: Agency Specifications

State/ Organization Agency Specs?

Material components Gradation

Mix design

Structural design

Lab tests

Field testing/ quality control

AL AL DOT

No answer

*

Alberta Alberta Infrastructure & Transportation Yes X X X

AR AR State Hwy. & Transportation Dept.

No answer

AZ AZ DOT No

answer

Coconino Co. Yes X X X X X X British Columbia

BC Ministry of Transportation

No answer

CA Caltrans (CA DOT) Yes X X X X

Co. of Lake, Dept. of Public Works No

Co. Riverside, Transportation Dept.

No answer

CO CO DOT Yes X X

CT CT DOT Yes X X X X

DE DE DOT Yes X X X

FL FL DOT No

answer

Orange Co. Public Works Yes X X X X

Palm Beach Co. No

answer

GA GA DOT Yes X X X X X

IA IA DOT Yes X X X X X X

ID Clearwater Co. Road & Bridge Yes X

East Side Hwy. District No

Franklin Co. Road & Bridge No

answer

Lost River Hwy. District No

answer

IL IL DOT No

Ogle Co. Hwy. Dept. Yes X X X X X

Knox Co. Hwy. Dept. Yes X X

Perry Co. Hwy. Dept. No

answer

KS KS DOT No

answer

KS DOT No

answer

Douglas Co. Public Works No

answer

Sedwick Co. Public Works Yes X X X X X X

Seward Co. Yes X X X X

KY No name given No

answer

MA MA Hwy. Dept. Yes X X X X

MD MD State Hwy. Admin. No

answer

Division of Public Works, Dept. of Hwys. & Transportation, Office of Transportation Engineering Yes X X X X X

ME ME DOT Yes X X X X X

35

MI MI DOT Yes X X

MI DOT Yes X X X

Dickinson Co. Road Commission Yes X X X

Grand Traverse Co. Road Commission

No answer

Kalamazoo Co. Road Commission Yes X

Kent Co. Road Commission Yes X X X X X X

Iona Co. Road Commission Yes X X X X

Iron County Road Commission

No answer

Muskegon Co. Road Commission Yes X X X

Oceana Co. Road Commission

No answer

Van Buren Co. Road Commission

No answer

MN MN DOT Yes X X X X

Fillmore Co. Yes X X X

Hennepin Co. No

answer

Rice Co. Hwy. Dept. Yes X X X X X X

Wright Co. Hwy. Dept. Yes X

MO MO DOT Yes X X X X X

Cole Co. Dept. of Public Works

No answer

Webster Co. Road & Bridge Dept.

No answer

MS MS DOT No

answer

MT MT DOT Yes X X X X X X

Blaine Co. Road Dept. No

Sheridan Co. No

answer

ND ND DOT Yes X X X X

NE Dept. of Roads (DOT) Yes X X X

Adams Co. Roads Yes X X X X X X

Arthur Co. Yes X X X X X

Burt Co. No

answer

Kearney Co. Roads Dept. No

answer

Keith Co. Hwy. Dept. No

answer

Lancaster Co. Engineering Dept.

No answer

Miller & Associates Consulting Engineers

No answer

Nuckolls Co. Road Dept. No

answer

Saunders Co. Hwy. Dept. No

answer

York Co. Hwy. Dept. No

answer

NH NH DOT Yes X X X

NJ NJ DOT No

answer

NY Genesee Co. Hwy. Dept. Yes X

Monroe Co. DOT Yes X X

OH OH DOT Yes

Delaware Co. Yes X X

Tuscarawas Co. Yes X

36

Ontario Ministry of Transportation of Ontario Yes X X X X X X

OR OR DOT No

answer

Quebec Ministere des transports du Quebec (Quebec DOT) Yes X X X X X X

Sasktchewan Sasktchewan Hwys. & Transportation Yes X X X X X

SD SD DOT Yes

Pennington Co. Hwy. Dept. Yes

TN TN DOT No

answer

TX TX DOT Yes X X X X X X

Bell Co. Engineer's Office No

Chambers Co. Yes X

UT UT DOT Yes X X X X X X

VA VA DOT Yes X X X

VT VT Agency of Transportation Yes X X X X X

WA WA DOT Yes X X

WI Bayfield Co. Hwy. Commissioner Yes X X X

Brown Co. Hwy Yes X X X X

Buffalo Co. Hwy. Dept. No

Dane Co. Public Works Hwy. & Transp. ….

Douglas Co. Hwy. Dept. Yes X X

Eau Claire Co. Hwy. Dept. No

Florence Co. Hwy. Dept. Yes X X X X X

Kenosha Co. Public Works Yes X

Kewaunee Co. Hwy. Dept. No

La Crosse Co. Hwy. Dept. No

Monroe Co. Hwy. Dept. No

Oconto Co. Hwy. Dept. Yes X

Richland Co. Hwy. Dept. No

USDA Forest Service Yes

Vernon Co. Hwy. Dept. No

answer

Vilas Co. Hwy. Dept. Yes X X X

Waqupaca Co. Hwy. Dept. No

Washburn Co. Hwy. Dept. Yes X X X X X

Washington Co. Hwy. Commission Yes X X X X

Waukesha Co. Dept. of Public Works Yes X X X X X X

WY WY DOT Yes X

FHWA Burley Hwy. District Yes X X X X X X

Fed. Lands Hwy. - W. Fed. Lands Hwy. Division Yes X X X X

Unknown Lincoln Parish Police Jury No

Unknown Yes X X * Relates to agencies that have never or have once used FDR, but since discontinued its use. Neither group was asked this question.

37

Appendix C

FDR Survey Analysis: 118 Eligible Respondents 118 Respondents Answered Question # 1 1 - Which statement best describes your agency’s experience with Full Depth Reclamation? 31 My agency has never used FDR 4 My agency once used FDR, but has discontinued its use 83 My agency continues to use FDR 31 Respondents Answered Question # 2 2 - If your agency has never used Full Depth Reclamation, why not? 11 No appropriate sites in my agency's jurisdiction 17 Lack of familiarity with FDR 7 Lack of contractors 6 Lack of specifications 0 Poor performance reported by others 10 Cost 5 Other 3 Keyword Matches for Question # 3 3 - When did your agency start using FDR? 1- 1985 1- 1987 1- 2000 3 Keyword Matches for Question # 4 4 - When did your agency stop using FDR? 1- 1987 1- 2000 1- 2005 4 Keyword Matches for Question # 5 5 - Approximately how many lane miles of FDR has your agency constructed? 1- 10 1- 14 1- 2.5 1- 20 4 Respondents Answered Question # 6 6 - Why did your agency discontinue using FDR? 3 No appropriate sites in my agency's jurisdiction 2 Unacceptable performance 2 Difficulty achieving compaction 0 Difficulty controlling thickness 0 Difficulty supporting construction equipment 1 Cost 2 Other 79 Keyword Matches for Question # 7 7 - When did your agency start using FDR? 1- 1970

38

1- 1975 2- 1978 2- 1980 1- 1982 1- 1983 4- 1985 1- 1987 4- 1988 8- 1990 1- 1991 3- 1992 1- 1993 4- 1994 9- 1995 3- 1996 6- 1997 5- 1998 3- 1999 6- 2000 4- 2001 2- 2002 6- 2003 1- 2004 3- 2005 76 Keyword Matches for Question # 8 8 - Approximately how many lane miles of FDR has your agency constructed? 1- 1 2- 4 1- 10 1- 12 1- 14 1- 17 1- 18 3- 20 4- 25 1- 27 4- 30 2- 31 1- 31.5 1- 34 5- 40 1- 44 4- 50 3- 60 1- 61 1- 65 1- 70 1- 77 1- 80 8- 100 3- 120 1- 125 4- 150 1- 160 1- 190

39

6- 200 1- 220 1- 250 2- 300 1- 340 1- 360 1- 560 1- 564 1- 720 1- 750 1- 1000 1- 6000 1- n/a 64 Respondents Answered Question # 9 9- On what type of highways does your agency use FDR? Interstate

…1 – 1% …1 – 3% …2 – 5% …1 – 10% …1 – 50% …1 – 68% Rural high-volume (>2000 ADT) highways …4 – 5% …1 – 7% …1 – 10% …4 – 15% …7 – 20% …4 – 25% …5 – 30% …1 – 33% …1 – 38% …2 – 40% …1 – 41% …11 – 50% …2 – 60% …1 – 67% …3 – 70% …1 – 75% …2 – 80% …8 – 100% Rural low-volume (≤ 2000 ADT) highways …2 – 10% …1 – 14% …3 – 20% …2 – 25% …2 – 30% …2 – 33% …1 – 35% …4 – 40% …1 – 45% …14 – 50% …3 – 55% …1 – 58% …3 – 60%

40

…4 – 70% …4 – 75% …2 – 80% …2 – 85% …1 – 90% …2 – 95% …18 – 100% Urban arterials and collectors …1 – 1% …5 – 5% …6 – 10% …1 – 15% …2 – 20% …2 – 25% …2 – 30% …1 – 33% …1 – 40% …1 – 50% Residential …1 – 1% …4 – 5% …4 – 10% …1 – 20% …2 – 30% …1 – 40% …1 – 50% Other …1 – 2% [interstate access roads] …1 – 10% [airport runways and taxiways] …1 – 60% [shoulders of 4-lane divided] …1 – 100% [any roadway with sand sub-base] 64 Respondents Answered Question # 10 10 – What types of surfacing does your agency apply to FDR? Hot mix asphalt …2 – 50% …1 – 40% …5 – 50% …2 – 80% …1 – 85% …2 – 90% …3 – 95% …1 – 98% …1 – 99% …57 – 100% Asphalt surface treatment …1 – 1% …1 – 2% …3 – 5% …3 – 10% …1 – 15% …1 – 20% …5 – 50% …1 – 60% …1 – 90% …1 – 95%

41

…5 – 100% Unpaved (no additional) surfacing …1 – 5% …1 – 10% 83 Respondents Answered Question # 11 11 - What are your agency’s selection criteria for the use of FDR? 40 Type of highway 38 Estimated traffic 72 Current highway condition 31 Drainage conditions 73 Existing subgrade and base conditions 47 Estimated cost 13 Other 81 Respondents Answered Question # 12 12 - Does your agency have specifications for the following? 42 Material components 52 Gradation 36 Mix design 28 Structural design 33 Laboratory tests 44 Field testing and quality control 13 None of the above 13 Other 85 Respondents Answered Question # 13 13 - With which admixtures does your agency have experience? 60 Bituminous (emulsions or foamed asphalt) 29 Chemical admixtures (cement, fly ash, or lime) 55 Mechanical (add virgin aggregate or recycled asphalt pavement) 4 None 10 Other 84 Respondents Answered Question # 14 14 - On average, how does the performance of pavements constructed with FDR compare to that of conventionally constructed pavements? 28 FDR performs better than conventional 51 FDR performs about the same as conventional 5 FDR performs worse than conventional 68 Respondents Answered Question # 15 15a - What problems, if any, has your agency experienced with the performance of pavements constructed with FDR? - - Load-related Cracking 4 Frequently 28 Occasionally 36 Rarely or Never 66 Respondents Answered Question # 16 15b - What problems, if any, has your agency experienced with the performance of pavements constructed with FDR? - - Reflective Cracking 2 Frequently 9 Occasionally 55 Rarely or Never

42

65 Respondents Answered Question # 17 15c - What problems, if any, has your agency experienced with the performance of pavements constructed with FDR? - - Block Cracking 0 Frequently 11 Occasionally 54 Rarely or Never 70 Respondents Answered Question # 18 15d - What problems, if any, has your agency experienced with the performance of pavements constructed with FDR? - - Transverse Cracking 5 Frequently 30 Occasionally 35 Rarely or Never 71 Respondents Answered Question # 19 15e - What problems, if any, has your agency experienced with the performance of pavements constructed with FDR? - - Rutting 3 Frequently 38 Occasionally 30 Rarely or Never 56 Respondents Answered Question # 20 15f - What problems, if any, has your agency experienced with the performance of pavements constructed with FDR? - - Stripping (in the FDR) 1 Frequently 4 Occasionally 51 Rarely or Never 2 Respondents Answered Question # 21 15g - What problems, if any, has your agency experienced with the performance of pavements constructed with FDR? - - Other 0 Frequently 0 Occasionally 2 Rarely or Never 64 Respondents Answered Question # 22 16 - What factor(s) contributed to these problems? 29 Inconsistent blend control 10 Excessive recycled asphalt pavement content 18 Inadequate depth control 39 Insufficient compaction 19 Subgrade disturbance during construction 25 Other 84 Respondents Answered Question # 23 17 - Does your agency plan to expand or reduce the use of FDR in the future? 14 We plan to significantly expand the use of FDR 65 We plan to continue the use of FDR at approximately the same level 5 We plan to significantly reduce the use of FDR 84 Respondents Answered Question # 24 18 - How many projects does your agency plan to construct with FDR within the next two years? 11 None 24 1-2 25 3-5 10 6-10

43

14 >10 77 Respondents Answered Question # 25 19 - On what types of highway do you plan to use FDR? 4 Interstate 48 Rural high-volume (>2001 ADT) highways 70 Rural low-volume (< 2000 ADT) highways 20 Urban arterials and collectors 9 Residential 5 Other 116 Respondents Answered Question # 26 20 - What level of interest does your agency have in collaborating with this study? 14 My agency is not interested in participating 96 My agency would like to receive information about the study as it progresses 43 My agency would share our specifications and construction procedures 23 My agency would assist with evaluation of the performance of our existing FDR projects 22 My agency would consider incorporating test sections into a planned FDR project 48 My agency would allow the SDSM&T team to observe the performance of existing FDR projects 42 My agency would allow the SDSM&T team to observe the construction of planned FDR projects 5 Other

Appendix D Table of States/Providences Asphalt Recycling Specifications

SD DOT ME DOT ME DOT GA DOT TX DOT MA DOT

Materials Process In-Place Surfacing

Full Depth Recycled Pavement (with Foamed Asphalt)

Full Depth Recycled Pavement (with Cement)

Lime Stabilized Reclaimed Base Construction

Fly Ash or Lime Treated Road-Mixed

Reclaimed Base Course

General

This work consists of salvaging granular material from the existing roadbed, processing, mixing and utilization of the material.

This work shall consist of pulverizing a portion of the existing roadway into a homogenous mass, treating the pulverized material with the foamed asphalt process and then placing and compacting this material to the lines, grades, and dimensions shown on the plans.

This work shall consist of pulverizing a portion of the existing roadway structure into a homogenous mass, stabilizing the material with cement and placing and compacting this material to the lines, grades, and dimensions shown on the plans.

This work consists of constructing a Lime Stabilized Reclaimed Base Course by pulverizing the existing pavement structure and mixing with hydrated lime, quicklime, or Portland cement to a specified depth.

Mix and compact water, fly ash, or lime and fly ash, and subgrade or base (with or without asphalt concrete pavement) in the roadway.

The work shall consist of manufacturing a stabilized base course through the recycling of the existing pavement structure and a specified depth of acceptable sub-base material is to be uniformly crushed, pulverized and blended, then spread, graded, and compacted to plans specifications.

Cement/ Portland Cement n/a

Shall be Type I or II meeting the requirements of AASHTO M85

Shall be Type I or II meeting the requirements of AASHTO M85 Shall be Type I or II. n/a n/a

Bitumen n/a n/a n/a

Use bituminous prime that consists of cutback asphalt with the following grades: RC-30, RC-70, RC-250, MC-30, MC-70, MC-250. n/a n/a

Emulsified/Foamed Asphalt n/a n/a n/a n/a n/a n/a

Fly Ash n/a n/a n/a n/a Use Class CS or FS as shown in the plans. n/a

45

IL DOT UT DOT NH DOT CO DOT CT DOT IA DOT

Materials Recycled Base Processed Pulverized Surfacing

Reclaimed Stabilized Base Full Depth Reclamation

Full Depth Reclamation Full Depth Reclamation

General

Work shall consist of the in-place recycling of the existing pavement by milling the existing hot mix asphalt, adding emulsified asphalt, shaping, and compacting the mixture. n/a

All overburden should be stripped before obtaining material from a source, the percent wear of base course material should not exceed 50% (AASHTO T 96) n/a n/a

Consists of reclaiming existing asphalt pavement to the width and depth specified in the contract documents, mixing the reclaimed material with stabilized agents, and compacting

Cement/ Portland Cement n/a

Must use type I or II Portland Cement; Follow Tables 1 and 3 in ASTM C150; cement should not contain lumps or be partially set; no air-entrained cement; may be tested for compliance at any time n/a n/a n/a

Portland cement meeting ASTM Type I

Bitumen n/a n/a

Shall conform to gradation requirements with a minimum of 1.5% n/a n/a n/a

Emulsified/Foamed Asphalt

Emulsified asphalt shall be CSS-1, applied a rate that will leave a residual asphalt content of 3.0% based upon dry weight of aggregate, or as determined by the laboratory. n/a n/a n/a n/a

Emulsified asphalt must meet requirement of Section 4140 of the Standard Specifications. Foamed asphalt must be using PG 52-34 asphalt binder meeting the requirement of Section 4137 of the Standard Specifications; shall be maintained at a temperature within ± 20oF of the optimum temperature established by the design.

Fly Ash n/a n/a n/a n/a n/a Can come from any available source.

46

MI DOT Saskatchewan H&T

Materials Full Depth Recycled Pavement

Reclaimed Base Course

General Full Depth Recycled Pavement

The work shall consist of a layer of screened or crushed sand or gravel, with or without binder, filler or blender sand added, placed on a prepared surface, to the lines, grades and dimensions shown on the plans.

Cement/ Portland Cement

Pulverized material shall consist of the existing bituminous pavement and a designated portion of the underlying gravel, pulverized, and blended into a homogenous mass n/a

Bitumen n/a n/a

Emulsified/Foamed Asphalt n/a n/a

Fly Ash n/a n/a

47


Lime/Limestone/ Hydrated Lime n/a

Must meet requirements AASHTO M216 n/a

Application rate for lime will be determined from laboratory tests.

Must use hydrated lime, commercial lime slurry, or quicklime as shown in the plans. n/a

Glass Cullet n/a n/a n/a n/a n/a n/a

Asphalt Binder n/a

Performance Grade 64-28 meeting AASHTO M320 n/a n/a n/a n/a

Curing Seal n/a n/a n/a n/a n/a n/a

Blotter Sand n/a n/a n/a n/a n/a n/a

Crusher Dust n/a

Shall be free of friable or deleterious material; 100% passing 0.5 inch sieve, 10-15% passing No. 200 sieve

Shall be free of friable or deleterious material; 100% passing 0.5 inch sieve, 10-15% passing No. 200 sieve n/a n/a n/a

Water Shall be free of all injurious matter.

Shall be clean and free from deleterious concentrations of acids, alkalis, salts or other organic or chemical substances.

Shall be clean and free from deleterious concentrations of acids, alkalis, salts or other organic or chemical substances.

Use water without detrimental quantities of oil, salt, alkalis, or vegetable matter. The total inorganic solids shall not exceed 0.20%.

Water must be free of industrial wastes and other objectionable matter. n/a

Sand/Gravel n/a n/a n/a n/a n/a n/a

Crushed Gravel n/a n/a n/a n/a n/a n/a

Porous Granular Material n/a n/a n/a n/a n/a n/a

Recycled material

Salvaged granular and asphalt mix material shall be processed to provide a nominal 1.5 inch maximum size.

Pulverized material shall consist of the entire existing bituminous pavement and a portion of the underlying gravel. Material will be processed to 100% passing 2 inch sieve. n/a

Must consist of materials found in the roadbed, base, subbase, or added materials. Particles of aggregate too large to pass through a 3 inch sieve or that contain vegetable matter must be removed. n/a n/a

48


Lime/Limestone/ Hydrated Lime n/a

Use when pulverizing surface has a PI ≥ 6 (hydrated lime) n/a n/a n/a

Shall come from limestone crushing operations (limestone)

Glass Cullet n/a n/a Meet AASHTO M318 requirements n/a n/a n/a

Asphalt Binder n/a n/a n/a n/a n/a Meet requirements of Article 4193

Curing Seal n/a

Liquid Type MC-70 or MC-250 per section 02745 Asphalt Material n/a n/a n/a n/a

Blotter Sand n/a

Manufactured sand 100% passing No. 4 sieve at 0% moisture n/a n/a n/a n/a

Crusher Dust n/a n/a n/a n/a n/a n/a

Water n/a

Must meet AASHTO T26 test standard, extraneous material should be screened out when pumping from streams, ponds, or lakes n/a n/a n/a n/a

Sand/Gravel n/a n/a

Maximum size shall not exceed 3/4 of the compacted depth of the layer being placed; never larger than 6 inches n/a n/a n/a

Crushed Gravel n/a n/a

At least 50% of the material retained on the 1 inch sieve shall have a fractured surface n/a n/a n/a

Porous Granular Material

Granular material shall have a top size of 6 inches and not more than 35% by weight passing the 2 inch sieve. n/a n/a n/a n/a n/a

Recycled material n/a n/a n/a n/a n/a

Shall be free of winter sand, granular fill and construction debris

49


Lime/Limestone/ Hydrated Lime n/a n/a

Glass Cullet n/a n/a

Asphalt Binder n/a n/a

Curing Seal n/a n/a

Blotter Sand n/a n/a

Crusher Dust n/a n/a

Water n/a n/a

Sand/Gravel n/a n/a

Crushed Gravel n/a n/a

Porous Granular Material n/a n/a

Recycled material n/a

The base aggregate shall be salvaged from the sub-base course or base course of highways or airports. Shall be composed of fragments of durable rock.

50

Construction SD DOT ME DOT ME DOT GA DOT TX DOT MA DOT

General

Materials encountered and other materials designated in the contract shall be blended to provide a uniform blend of all materials before laydown.

First a uniform layer of crusher dust shall be spread before new aggregate or recycled material is added. Dry stabilizing agents shall then be uniformly spread prior to each pass of the foaming operation and the blended into a homogenous mass.

A uniform layer of crusher dust is applied to full width of roadway. New aggregate and recycled material will be added as necessary to restore cross-slope and/or grade. The cement shall be spread uniformly over the full width of the roadway to be recycled just prior to each pass of the stabilizing operation by means of a mechanical spreader.

Apply lime and cement according to the rate specified by the Engineer and mix to the depth shown on the plans. Maintain the application rate within ±10% of that specified by the Engineer.

The Engineer will determine the fly ash or lime-fly ash content and optimum content in accordance with Tex-127-E or prior experience with the materials. When treating existing materials, limit the amount of asphalt concrete pavement to no more than 50% of the mix.

Prior to starting the Contractor shall locate and protect existing drainage, utility and underlying structures. Each sequence of the reclamation process shall be 1.6 kilometers wide and shall be placed before starting next sequence.

Pulverized Material/Gradation

Asphalt and granular material shall be processed so that a uniform blend is obtained. Materials shall be processed and hauled to avoid contamination and loss.

100% passing 2 inch sieve. Material shall be fine-graded to a ±0.5 inch tolerance.

100% passing 2 inch sieve. Material shall be fine-graded to a ±0.5 inch tolerance.

Lime mixture must pass 100% passing the 2 inch sieve and 60% passing No. 4 sieve. Cement mixture must have 95% passing the 2 inch sieve and 55% passing the No. 200 sieve.

100% of base and subgrade passing the 1.75 inch sieve, 85% base and subgrade passing the 3/4 inch sieve and 60% of subgrade passing No. 4 sieve.

Gradation will be determined by the Engineer from the test results.

Final Composition/ Moisture

Moisture content of material shall be uniform for the full depth and extent of each layer. n/a n/a

Adjust the moisture content of the roadway materials to within 100 to 120% of the optimum moisture content immediately before spreading lime or cement.

Before applying lime, bring the prepared roadway to approximately optimum moisture content. Aerate to bring each layer to the moisture content directed during compaction. n/a

Prepare Roadbed/Placing

Placement operations shall commence immediately in conjunction with processing. Blended materials shall be placed in layers not exceeding 4 inches in thickness. n/a

The entire depth of existing pavement shall be pulverized together with approximately 1 inch of the underlying gravel into a homogenous mass.

For lime and cement stabilized base, road is prepared by loosing and pulverizing the in-place pavement structure to the width and depth to be stabilized without damaging the underlying materials. If necessary, add water to assist in pulverization.

When shown on the plans proof-roll the roadbed before pulverizing or scarifying existing material. Provide a uniform mixture to specified depth before adding lime or fly ash.

The existing pavement shall be swept with a power sweeper to remove all undesirable material. Existing pavement shall be sawcut in areas where the adjacent surface is to be protected.

51


General

After existing pavement has been milled, it shall be shaped and compacted to the satisfaction of the Engineer. In construction the existing subgrade shall be removed to a depth and replaced with Porous Granular Material. n/a

Reclaimed stabilized base may be used instead of crushed gravel or stone if certain requirements are met.

Consists of cutting the existing mat, pulverizing the existing asphalt with the existing subgrade and/or base course n/a n/a


100% passing 1.5 inch sieve, 90±5% passing 1 inch sieve, 60±15% passing 0.5 inch sieve.

100% passing 3 inch sieve; 95-100% passing 2 inch sieve

100% passing 3 inch, 80-100% passing 1.5 inch, 55-90% passing 3/4 inch, 40-70 passing No 4 sieve

99% passing 1.5 inch sieve.

90-100% passing 3.5 inch sieve

Top size of the material shall not exceed 25% of the depth of the compacted recycled mat; 98-100% passing the 1.5 inch sieve, 90-100% passing the 1 inch sieve

Final Composition/ Moisture

Prior to adding emulsion, aggregate moisture content shall be a maximum of 2.5%. After the addition of the emulsion material shall be aerated until a moisture content of 5% of less has been achieved.

Add water to bring mixture up to 4% above the optimum moisture content (AASHTO T-180) n/a

Water shall be evenly distributed to within 2% of the optimum moisture as determined by AASHTO T-180, Method D

Existing bituminous concrete pavement and underlying material must be pulverized and mixed to form a homogenous mixture.

Additional water may need to be added to facilitate uniform mixing and achieve a stable reclaimed layer above the minimum specified density.


The contractor shall use a bituminous paver or spreader to place the recycled material. Heating will not be permitted.

Pulverize and blend 8 inches of treated material; 6 inches of existing asphalt and 2 inches of Untreated base or Cement Treated base, with final blend meeting Pulverized Material blend

The subgrade should be smooth and free of holes and ruts; stones larger than 3 inches should be removed from the upper 4 inches by scarifying the surface.

Specified as a total processed depth of up to 8 inches; depths between 8-16 inches as appropriate

Roadway shall be reclaimed to a depth of 10 inches from the top of the existing pavement surface, unless otherwise specified

All vegetation and debris within the width of pavement to be reclaimed should be removed.

52


General n/a

The contractor may use any construction method to salvage the base course or sub-base material. The material shall be handled so that there is no separation between the coarser and finer fractions.


100% passing the 2 inch sieve; it shall be free of winter sand, granular fill, construction debris, and other material not generally considered bituminous pavement.

When the lift of base course is less than eight cm the maximum particle size shall not be more than 1/2 of the depth of the lift. .

Final Composition/ Moisture n/a

The moisture content of the base mix shall not be greater than 5% by weight when it leaves the pugmill.


Entire depth of existing pavement along with 1 inch of the underlying material shall be pulverized into a homogenous mass. n/a

53


Grade n/a

The completed shall be shaped, and maintained to a tolerance of ±3/8 of an inch.

The completed shall be shaped, and maintained to a tolerance of ±3/8 of an inch. n/a n/a

The reclaimed material shall be rolled, compacted and fine graded to the specified cross sections and/or grades in plans.

Density

Each layer shall be watered and rolled. This process shall continue until density is not increased by 1% or more from previous roller pass.

Must achieve at least 98% density. n/a

98% of the maximum dry density.

Subgrade must have a density of at least 95% of the maximum density. The bottom of the base course must be at least 95% of the maximum density and the subsequent courses treated must be at least 98% of the maximum density.

The required density shall be measured by a Nuclear Density Gauge supplied by the Department

Additive Mixing n/a

The Department will provide mix design including: % of bitumen, % of water to be used in process, quantity of lime, cement and crusher dust, optimum moisture content and amount of additional aggregate.

The Department will provide mix design including: % of Portland cement, optimum moisture content for proper compaction and amount of additional aggregate.

For lime add water during mixing if necessary, even if the material has optimum moisture content to sustain the chemical reaction between lime and water. Begin mixing as soon as the lime of cement is spread and continue until a homogenous and uniform material is produced.

Lime mixture must be allowed to mellow for 1 to 4 days. Sprinkle the treated materials during the mixing and mellowing operation to achieve adequate hydration and proper moisture content. Thoroughly dry-mix fly ash using approved equipment. n/a

Reclaiming Operations n/a

Asphalt binder shall be added to the milling machine by pumping from a mobile bulk tanker. Temperature must be maintained at 375oF. Water will be added during recycling process to meet moisture requirements. n/a

The lime is first spread, mixed, allowed to mellow to a loam consistency and compacted. The portland cement must be uniformly spread with a cyclone-type mechanical spreader. Pass only spreading and mixing equipment over the spread cement.

Distribute the required quantity of dry hydrated lime with approved equipment. Only hydrated lime may be distributed by bag. Slurry placement must be distributed uniformly by making successive passes over roadway until specified lime content is reached.

In any section the reclamation work shall be done on one half the road width at one time. One way traffic will be permitted during working hours with traffic police present. Two-way traffic will be permitted all other times.

54


Grade

Any rutting, shoving, rolling, or deflection of one inch or greater, the areas shall be considered for base or subgrade repair.

Surface deviations should not be more than 3/4 inch in 10 feet n/a

Equipment must have automatic controls to determine transverse slope within 0.01% of specified.

When the proposed subgrade elevation is achieved, the reclaimed material will be placed on roadway in lifts no greater than 5 inches.

The crown of the compacted reclaimed mat shall be within 6 inches of the centerline established by the construction survey; bumps and dips and the cross-slope shall be with 1 inch of designated slope.

Density

Density in field shall be a minimum of 92% of laboratory design. n/a

The density shall not be less than 95% of the maximum density determined by the Standard Proctor Test (AASHTO T99)

Must meet a minimum of 95% of the maximum dry density in accordance with AASHTO T-180, Method D

The reclaimed subbase material shall be a minimum of 95% of the proctor wet density (AASHTO T-180D)

Shall be a minimum of 94% of laboratory density based on the dry unit weight of compacted material. The surface density based on the 2 inch depth nuclear probe density, shall be a minimum of 97% of the nuclear probe density measured at 75% of the reclaimed mat depth. Nuclear gauge moisture and density tests should be performed every 500 feet.

Additive Mixing n/a

Add 2% by dry unit weight PC to the pulverized surface, must be added using a calibrated meter

The pulverize shall blend the existing pavement and base course into a homogenous mass using the bitumen as a stabilizer.

Mixing of the different materials shall create a homogenous mixture. n/a

Application rate of 3% by dry mass

Reclaiming Operations n/a n/a n/a n/a n/a n/a

55


Grade

Complete surface shall be shaped and maintained to a tolerance of ±3/8 inches of the required shape. n/a

Density

Will be determined using a Nuclear Density Gauge. The FDR material shall be compacted to a minimum density of 98% of the target density as determined in the control section

Each lift shall be compacted to not less than 100% of the maximum density. When excess moisture exists in the base course it shall be dried at no direct expense to the Department.

Additive Mixing n/a

Mixing operations shall be carried out in a stationary mixing plant. When a continuous-type plant is used the base aggregate, water and/or binder and/or filler and/or blender feeds must be accurately controlled and dry mixed until uniformly distributed.

Reclaiming Operations n/a

The thickness of any compacted base course lift shall not be less than 4 cm and not greater than 10 cm. The base aggregate or mix shall be spread be blade patrols or other equipment approved by the Engineer.

56


Equipment

Processing and blending may be accomplished in place providing the Contractor's method meets the blending and gradation requirements and has positive depth control. Processing of material shall include all existing asphalt surfacing.

Shall have a minimum of 600 horsepower, two microprocessor-controlled systems, with 2 independent pumping systems and spraybars, to regulate the application of foamed bitumen stabilizing agent. Spray bars must have self-cleaning nozzles. A test nozzle must be fitted at one end of the spraybar. An electrical heating system must maintain the temperature of all bitumen flow components above 150oC. The spray bar must have individual expansion chambers into which both hot bitumen and water are injected under pressure through individual orifices that promote atomization. Must be fitted with a front breaker bar to break down material into specified sizes.

The pulverize shall be self-propelled, specifically manufactured for full-depth recycling and capable of reducing material to specified sieve size. Must be equipped with automatic depth controls and maintain a constant cutting depth and width and a gauge to show depth of material being processed.

Equipment must be capable of continuously mixing materials to a constant depth and providing a homogenous blend. Spreaders must be capable of uniformly distributing bulk lime or lime slurry to the actual application rate. Mixing and scarifying equipment must be capable of ensuring positive depth control. Type and weight of equipment used for applying water and prime must not damage the lime-stabilized reclaimed base.

Slurry tanks must be equipped with agitation devices to slurry hydrated lime or quicklime on the project. The pulverization equipment must cut and pulverize material uniformly to the proper depth with cutters that will plane to a uniform surface over the entire width of the cut, provide a visible indication of the depth of cut at all times and uniformly mix the materials.

Machine shall have a positive depth control to insure a uniform depth and shall have the ability to process the complete depth specified into a homogenous mass and crush all oversize material larger than 200 mm in diameter.

Compaction/ Rollers

The final rolling of the top surface of the granular material shall embed as many loose stones as possible. The finished surface shall be smooth and free from waves and inequalities.

Material shall be rolled with a vibratory pad/tamping foot roller, vibratory steel drum soil compactor and a Type II pneumatic roller. After compaction, the roadway surface shall be treated with a light application of water and rolled with pneumatic-tired rollers.

Material shall be rolled with a vibratory pad/tamping foot roller, vibratory steel drum soil compactor and a Type II pneumatic roller.

Compact lime layers with a sheepsfoot-type roller, until the entire depth of the mixture is at least 98% of the maximum dry density. Cement compaction must begin within 45 minutes from the time water is added to the cement mixture and must be completed within 2 hours.

All compaction must be completed within 6 hours of fly ash application using density control. Rolling should begin at the sides and proceed towards the center. Rollers should be between 2 and 6 MPH.

At least one vibratory roller shall be used on each reclaimed surface and shall have a compacting width of not less than 1.5 meters and have a gross mass of not less than 14.6 metric tons.

57


Equipment

Rollers shall be a combination of Pneumatic Tired and Steel Wheel capable of deriving the required compaction. Mixer shall be capable of mixing the milled material and Emulsified into a homogenous mixture and shall place the mixture in a spreader, widrew, truck, or hopper of a paver in one continuous operation. Separate diesel engines for cutter and travel drives and a 12 foot wide floating moldboard with mechanical stroke limit, and adjustable down position to control depth.

Use a road mix machine or cross shaft mixer capable of introducing water at time of mixing

Milling machine is not permitted, reclaiming equipment must be equipped with a gauge to show the depth of the material. Equipment must be of adequate size to produce required material and capable of removing excess fines; glass cullets must be mixed with base course prior to being placed on roadway.

The mixing machine shall make as many passes as necessary to create a homogenous mixture.

Must use a self-propelled, traveling rotary reclaimed capable of cutting through existing bituminous concrete pavement up to 10 inches; with an adjustable grading blade.

Machine must be self-propelled and capable of reclaiming the existing paving material to the width and depth specified with an automatic depth control, and capable of mixing material to the required gradation; machine shall provide a means for controlling the rate of flow and delivery of stabilizing agent. When using foamed asphalt the specified percentage of water shall be added accurately and uniformly to the hot asphalt binder and be fitted with a test nozzle to provide field samples and be equipped with a thermometer to measure the temperature of asphalt.

Compaction/ Rollers

After compaction has been attained, the base shall be proof rolled with a 18,000 pound per axle single unit vehicle to determine the areas of base or subgrade failure. Proof rolling shall consist of a minimum of four passes, two each lane, one pass at edge of pavement and one adjacent to the pavement centerline.

Compact cement treated mixture to 95% of Maximum Laboratory density (AASHTO T-180) within 60 minutes of addition cement and water; final grade should be 1 inch above original grade

Prior to compactions water must be applied; requires a sheep's foot or pad foot roller of at least 50,000 lb of dynamic force and a final rolling by a smooth steel wheel vibratory roller of 27,000 lb.

Will be measured for the top eight inch lift of reclaimed material; acceptance testing will be based on a random schedule of 1/400 square yards

At least one vibratory roller having a compaction width of not less than 5 feet and a gross weight of not less than 10 tons and be capable of producing high amplitude and low frequency vibrations.

If multiple passes are used a minimum of a six inch overlap shall be used. Initial rolling should be done with a sheepsfoot roller and shall be repeated within the next two calendar days to achieve the target density.

58


Equipment

Shall be self-propelled and equipped with standard automatic depth controls and must maintain a consistent cutting depth and width and be equipped with a gauge to show depth of material being processed. n/a

Compaction/ Rollers

Material shall be rolled with a vibratory pod/tamping foot roller; final rolling shall be done using a minimum 84 inch width single vibratory soil compactor.

When necessary for compaction water shall be added to the base course. Watering and rolling shall be controlled to prevent pumping the fines to the surface. The finished surface of the base course shall be true to grade and cross-section and free of any ruts or irregularities.

59


Procedure for a Control Strip/ Test Pits n/a

The Contractor shall construct a test strip at least 100 meters long and a full lane width. The test strip must demonstrate that the equipment and processes can produce recycled layers to meet the requirements. The test strip also determines the effect on the gradation on the recycled material by varying the forward speed and determine the sequence and manner of rolling necessary to obtain the compaction requirements. The full recycling production will not start until a passing test strip has been accomplished.

Test strip is prepared to make necessary adjustments to the mix design. The Contractor shall construct a test strip at least 100 meters long and a full lane width. The test strip must demonstrate that the equipment and processes can produce recycled layers to meet the requirements. The test strip also determines the effect on the gradation on the recycled material by varying the forward speed and determine the sequence and manner of rolling necessary to obtain the compaction requirements. The full recycling production will not start until a passing test strip has been accomplished.

The first section of each mixing operation will be a test section between 350 and 500 feet long. The length of the lime test section will be the length required to use all of the lime contained in one truck. The test section must demonstrate the acceptability of the equipment and methods used. If changes in methods or equipment are made during the project, additional test sections shall be constructed. The engineer will evaluate the compaction, moisture, homogeneity, thickness of stabilization and finished base surface. n/a

The Department will take and analyze test pits to the depth to be recycle. The following information is provided for each pit: location, depth of existing bituminous material and existing underlying aggregate gradation. This information is an indication of the existing conditions. Any gradation deficiencies indicated in test pits shall be corrected by blending the appropriate aggregate sizes into the mixture. A test section shall be constructed approximately 150 meters long and one lane wide within the project limits. Forward speed and processing direction will be recorded and material will be analyzed by the Engineer.

Curing n/a n/a n/a

After the lime-stabilized reclaimed base course has been finished it must be kept moist for 7 days. Apply a bituminous prime material no later than 24 hours after completing the finishing operations.

The lime-fly ash sections must cure for 7 days before adding another course or opening traffic. The fly ash treated sections must cure for 24 hours before opening to traffic. The treated course must dry for 48 hours before applying a prime coat. n/a

60

Weather Considerations n/a

Shall be between either May 15 and September 15 or May 1 and September 30 depending upon region. The temperature is 50oF or above in the shade. There cannot be any standing water or the ground can't be frozen, or isn't too windy that lime or cement can't be spread.

Shall be between either May 15 and September 15 or May 1 and September 30 depending upon region. The temperature is 50oF or above in the shade. There cannot be any standing water or the ground can't be frozen, or isn't too windy that cement can't be spread.

Air temperature must be above 40oF in the shade. The moisture of the materials to be used in the mixture must meet the specified limits. If the rain increases the cement's moisture content outside the specified limits the area affected must be tested for unconfined compressive strength.

Air temperature must be at least 40oF. Lime or fly ash cannot be applied when the conditions are windy.

Reclaiming operations shall not be permitted when the existing pavement or sub-base contains frost is excessively wet. The air temperature must be above 5oC. This process must take place between April 15 and October 15.

61


Procedure for a Control Strip/ Test Pits n/a n/a n/a n/a n/a

Test strips may be required to check target density

Curing n/a

Apply curing seal to surface as soon as possible but no later than 24 hours after completion of final day's rolling; apply at a rate of 0.25 gallons per minute n/a n/a n/a n/a

Weather Considerations

Work shall be done only between May 1 and September 1. Bituminous materials shall be applied and placed only when the air temperature, in the shade, is above 60oF. No work shall be done if rain is imminent. n/a

Asphalt cannot be applied if the temperature is below 50oF n/a n/a

FDR shall be preformed between April 1 and November 1, or when weather conditions are such that proper mixing, shaping, and compacting cannot be accomplished.

62


Procedure for a Control Strip/ Test Pits

A 300 foot section at the start of the pulverizing operations will be designated as the control section. The control section will be pulverized, have water added until testing indicated that optimum moisture has been obtained, and rolled as directed until the nuclear density readings show an increase in dry density of less than 1 lb/ft3 for the final 4 vibratory roller passes. This density will be used as the target density for the recycled material. n/a

Curing n/a

A prime coat shall be placed on the finished final lift of base course.

Weather Considerations

FDR shall not be preformed when weather conditions are such that proper pulverizing, spreading, or compaction cannot be accomplished.

Base aggregate or mix shall not be spread and compacted when the atmospheric temperature is 2oC or less.

63


Other n/a

No new pavement shall be placed on the full depth recycled pavement until a curing period of 48 hours has elapsed. n/a

Do not mix lime with frozen soils or soils containing permafrost. Construction joints should be formed at the end of each working day

Storage of quicklime, dry hydrated lime, and fly ash must be in closed, weatherproof containers.

All drainage utility and municipality structures are to be lowered to a minimum depth of 150 mm below bottom of reclaimed base course.

QC/QA Testing

A tolerance of 5% in material retained on the 1 inch sieve will be permitted provided all material passes the two inch sieve.

QC includes testing density, air temperature, surface temperature, and yield of all materials. QA includes in-place density. The Department can view or request a QC test at any time. The contractor must operate in accordance with the approved Quality Control Plan.

QC includes testing density, air temperature, surface temperature., and yield of all materials. QA includes in-place density. Operations must cease if the computed yield differs from the approved Job Mix Formula by 10% or more, if the Contractor fails to achieve 98% density or fails to follow the approved QCP.

QA requirements for lime stabilized base include thickness, density, gradation and finishing requirements. QA requirements for cement stabilized base include; compaction and gradation tests, finished surface, thickness tolerance, and strength testing. The compressive strength must be 300 psi or greater for there to be no corrective work.

The Engineer may accept the section if no more than 1 of the 5 most recent density tests is below the specified density and the failing test is no more than 3 pcf below the specified density.

Failure to meet gradation requirements or insufficient production rate may be considered cause for rejection of the equipment, the construction methods or both. Engineer shall perform a sieve analysis on the reclaimed material every 4200 square meters.

Method of Payment & Measurement

Salvage, Process, and Utilize Existing Surface will be measured by the square yard and will be paid for at the contract unit price per square yard.

Full depth recycled material (including the foamed asphalt) will be measured by the square meter and will be paid for per square meter.

Full depth recycled material (including the foamed asphalt) will be measured by the square meter and will be paid for per square meter.

Lime is measured and paid for by the ton. Base material is measured by the square yard and portland cement is measured by the ton.

Lime, quicklime, and dry fly ash will be measured by the ton. Lime and fly ash will be paid for at the unit bid price.

Reclaimed Base Course shall be measured in place to the limits specified on the plans. Measured material shall be paid for at the contract unit price bid per square meter. Unit price shall also include all compensation for all crushing, pulverizing, blending, spreading, grading and compacting.

* All specifications are correct unless otherwise stated in the contract documents.

64


Other

Blotter sand is applied at a rate of 6 to 12 pounds per square yard, if travel is immediately after construction. n/a n/a

Drop inlets or catch basins that could be affected shall be sufficiently barricaded to prevent runoff

The material stabilizing agent can be added in dry or slurry form.

QC/QA Testing n/a n/a

Gradation testing procedures should be in accordance with AASHTO T27; sample for testing shall be taken from each lift n/a n/a

Residual asphalt content and the mineral stabilizing agent shall be controlled within ± 0.5% of the target established by the design.


Payment will be made for the quantities shown in the contract for the various items involved. This work shall be paid for at the contract unit prices per gallon for Bituminous Materials and per square yard for Recycled Base.

Pay deductions will apply to gradation, density, cement content and water content derivation from specified

Based upon total quantities in square yards (square meters)

Based upon total quantities in square yards.

Based upon total quantities in square yards; with areas not in allowable tolerance being corrected with no additional cost to the state.

Measured in square yards from the measured longitudinal length; payment shall be full compensation for all labor, equipment, and materials necessary for preparation, reclaiming, shaping, and compaction; asphalt and mineral stabilizing agents are measured per unit ton

65


Other n/a n/a

QC/QA Testing n/a

Test results of the section average not less than 100% of maximum density. All individual test results within the section are greater than 98% of maximum density.


Quantity is based upon total square yard; payment will be based upon the contract unit price per square yard, as well as full compensation for furnishing all equipment and labor for pulverizing, blending, placing, grading, and all incidentals necessary to complete the work.

Reclaimed base course will be made at the unit price per ton.

Appendix E

Suggested Construction Specification for Full-Depth Reclamation 1. GENERAL 1.1 Description. Full-depth reclamation (FDR) with cement, shall consist of pulverizing and mixing existing asphalt pavement and base course material with portland cement, soil and water to produce a dense, hard, cement-treated base. It shall be proportioned, mixed, placed, compacted, and cured in accordance with this specification, and shall conform to the lines, grades, thicknesses, and typical cross sections shown in the plan. 1.2 Caveat. This specification is intended to serve as a guide to format and content for normal FDR construction. Most projects have special features or requirements that should be incorporated in the project documents. 2. MATERIALS 2.1 Recycled Asphalt Pavement (RAP) and Base Material. Shall consist of the existing asphalt pavement, existing base course material and/or subgrade material. The base course and subgrade material shall not contain roots, topsoil, or any material deleterious to its reaction with cement. The particle distribution of the processed material shall be such that 100% passes a 3-inch (75 mm) sieve, at least 95% passes a 2-inch (50 mm) sieve, and at least 55% passes a No. 4 (4.75 mm) sieve. 2.2 Portland Cement. Shall comply with the latest specifications for portland cement (ASTM C 150, ASTM C 1157, or AASHTO M 85) or blended hydraulic cements (ASTM C 595, ASTM C 1157, or AASHTO M 240). 2.3 Water. Shall be free from substances deleterious to the hardening of the cement-treated material. 2.4 Pozzolans. If used, pozzolans including fly ash, slag, and silica fume shall comply with the appropriate specifications (ASTM C 618, AASHTO M 295 for fly ash; ASTM C 989, AASHTO M 302 for slag; and ASTM C 1240 for silica fume). 3. EQUIPMENT 3.1 Description. FDR may be constructed with any machine or combination of machines or equipment that will produce a satisfactory product meeting the requirements for pulverization, cement and water application, mixing, compacting, finishing, and curing as provided in this specification.

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3.2 Mixing Methods. Mixing shall be accomplished in place, using single-shaft or multiple-shaft mixers. Agricultural disks or motor graders are not acceptable mixing equipment. 3.3 Cement Proportioning. Cement can be added in a dry or slurry form. If applied in slurry form, the slurry mixer and truck shall be capable of completely dispersing the cement in the water to produce a uniform slurry, and shall continuously agitate the slurry once mixed. 3.4 Application of Water. Water may be applied through the mixer or with water trucks equipped with pressure-spray bars. 3.5 Compaction. The processed material shall be compacted with one or a combination of the following: tamping or grid roller, pneumatic-tire roller, steel-wheel roller, vibratory roller, or vibrating-plate compactor. 4. CONSTRUCTION REQUIREMENTS 4.1 General 4.1.1 Preparation of Subgrade. Before processing begins, the area to be processed shall be graded and shaped to lines and grades as shown in the plans or as directed by the engineer. During this process, any unsuitable soil or material shall be removed and replaced with acceptable material. Any manholes, valve covers, or other buried structures shall be protected from damage prior to processing. The subgrade shall be firm and able to support, without yielding or subsequent settlement, the construction equipment and the compaction of the FDR material. Soft or yielding subgrade shall be corrected and made stable before construction proceeds. 4.1.2 Mixing and Placing. FDR processing shall not commence when the soil aggregate or subgrade is frozen, or when the air temperature is below 40°F (4°C). Moisture in the base course material at the time of cement application shall not exceed the quantity that will permit a uniform and intimate mixture of the pulverized asphalt, base material and cement during mixing operations, and shall be within 2% of the optimum moisture content for the processed material at start of compaction. The operation of cement application, mixing, spreading, compacting, and finishing shall be continuous and completed within 2 hours from the start of mixing. Any processed material that has not been compacted and finished shall not be left undisturbed for longer than 30 minutes.

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4.2 Pulverization/Mixing 4.2.1 Preparation. The surface of the pavement prior to mixing shall be at an elevation so that, when mixed with cement and water and recompacted to the required density, the final elevation will be as shown in the plans or as directed by the engineer. The material in place and surface conditions shall be approved by the engineer before the next phase of construction is begun. 4.2.2 Scarifying. Before cement is applied, initial pulverization or scarification may be required to the full depth of mixing. Scarification or pre-pulverization is a requirement for the following conditions: 1) When the processed material is more than 3% above or below optimum moisture

content. When the material is below optimum moisture content, water shall be added. The pre-pulverized material shall be sealed and properly drained at the end of the day or if rain is expected.

2) For slurry application of cement, initial scarification shall be done to provide a

method to uniformly distribute the slurry over the processed material without excessive runoff or ponding.

4.2.3 Application of Cement. The specified quantity of cement shall be applied uniformly in a manner that minimizes dust and is satisfactory to the engineer. If cement is applied as a slurry, the time from first contact of cement with water to application on the soil shall not exceed 60 minutes. The time from cement placement on the soil to start of mixing shall not exceed 30 minutes. 4.2.4 Mixing. Mixing shall begin as soon as possible after the cement has been spread and shall continue until a uniform mixture is produced. The mixed material shall meet the following gradation conditions: 1) The final mixture (bituminous surface, granular base, and subgrade soil) shall be

pulverized such that 100% passes the 3-inch (75 mm) sieve, at least 95% passes the 2-in. (50 mm) sieve, and at least 55% passes the No. 4 (4.75 mm) sieve. No more than 50% of the final mixed material shall be made of the existing bituminous material unless approved by the engineer and included in a mixture design. Additional material can be added to the top or from the subgrade to improve the mixture gradation, as long as this material was included in the mixture design.

2) The final pulverization test shall be made at the conclusion of mixing operations.

Mixing shall be continued until the product is uniform in color, meets gradation requirements, and is at the required moisture content throughout. The entire operation of cement spreading, water application, and mixing shall result in a uniform pulverized asphalt, soil, cement, and water mixture for the full design depth and width.

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4.3 Compaction. The processed material shall be uniformly compacted to a minimum of 98% of maximum density based on a moving average of five consecutive tests with no individual test below 96%. Field density of compacted material can be determined by nuclear method in the direct transmission mode (ASTM D 2922, AASHTO T 310), sand cone method (ASTM D 1556, AASHTO T 191), or rubber balloon method (ASTM D 2167). Optimum moisture and maximum density shall be determined prior to start of construction and also in the field during construction by a moisture-density test (ASTM D 558 or AASHTO T 134). At the start of compaction, the moisture content shall be within 2% of the specified optimum moisture. No section shall be left undisturbed for longer than 30 minutes during compaction operations. All compaction operations shall be completed within 2 hours from start of mixing. 4.4 Finishing. As compaction nears completion, the surface of the FDR material shall be shaped to the specified lines, grades, and cross sections. If necessary or as required by the engineer, the surface shall be lightly scarified or broom-dragged to remove imprints left by equipment or to prevent compaction planes. Compaction shall then be continued until uniform and adequate density is obtained. During the finishing process the surface shall be kept moist by means of water spray devices that will not erode the surface. Compaction and finishing shall be done in such a manner as to produce a dense surface free of compaction planes, cracks, ridges, or loose material. All finishing operations shall be completed within 4 hours from start of mixing. 4.5 Curing. Finished portions of the FDR base that are traveled on by equipment used in constructing an adjoining section shall be protected in such a manner as to prevent equipment from marring or damaging completed work. After completion of final finishing, the surface shall be cured by application of a bituminous or other approved sealing membrane, or by being kept continuously moist for a period of 7 days with a water spray that will not erode the surface of the FDR base. If curing material is used, it shall be applied as soon as possible, but not later than 24 hours after completing finishing operations. The surface shall be kept continuously moist prior to application of curing material. For bituminous curing material, the FDR base surface shall be dense, free of all loose and extraneous materials, and shall contain sufficient moisture to prevent excessive penetration of the bituminous material. The bituminous material shall be uniformly applied to the surface of the completed cement-treated material. The exact rate and temperature of application for complete coverage, without undue runoff, shall be specified by the engineer. Should it be necessary for construction equipment or other traffic to use the bituminous-covered surface before the bituminous material has dried sufficiently to prevent pickup, sufficient sand cover shall be applied before such use.

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Sufficient protection from freezing shall be given the cement-treated material for 7 days after its construction or as approved by the engineer. 4.6 Traffic. Completed portions of FDR base can be opened immediately to low-speed local traffic and to construction equipment, provided the curing material or moist curing operations are not impaired, and provided the FDR base is sufficiently stable to withstand marring or permanent deformation. The section can be opened up to all traffic after the FDR base has received a curing compound or subsequent surface and is sufficiently stable to withstand marring or permanent deformation. If continuous moist curing is employed in lieu of a curing compound or subsequent surfacing within 7 days, the FDR base can be opened to all traffic after the 7-day moist curing period, provided the FDR base has hardened sufficiently to prevent marring or permanent deformation. 4.7 Surfacing. Subsequent pavement layers (asphalt, chip-seal, or concrete) can be placed any time after finishing, as long as the soil-cement is sufficiently stable to support the required construction equipment without marring or permanent distortion of the surface. 4.8 Maintenance. The contractor shall maintain the cement-treated material in good condition until all work is completed and accepted. Such maintenance shall be done by the contractor at his own expense. Maintenance shall include immediate repairs of any defects that may occur. If it is necessary to replace any processed material, the replacement shall be for the full depth, with vertical cuts, using either cement-treated material or concrete. No skin patches will be permitted. 5. INSPECTION AND TESTING 5.1 Description. The engineer, with the assistance and cooperation of the contractor, shall make such inspections and tests as deemed necessary to ensure the conformance of the work to the contract documents. These inspections and tests may include, but shall not be limited to: 1) Obtaining test samples of the cement-treated material and its individual components

at all stages of processing and after completion. 2) Observing the operation of all equipment used on the work. Only those materials,

machines, and methods meeting the requirements of the contract documents shall be used unless otherwise approved by the engineer.

All testing of processed material or its individual components, unless otherwise provided specifically in the contract documents, shall be in accordance with the latest applicable ASTM or AASHTO specifications in effect as of the date of advertisement for bids on the project.

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6. MEASUREMENT AND PAYMENT 6.1 Measurement. This work will be measured: 1) In square yards (meters) of completed and accepted FDR base course as

determined by the specified lines, grades, and cross sections shown on the plans. 2) In tons (tonnes) or cwt of cement incorporated into the FDR base course in

accordance with the instructions of the engineer. 6.2 Payment. This work will be paid for at the contract unit price per square yard (meter) of FDR base course and at the contract unit price per ton (tonne) or cwt of cement furnished, multiplied by the quantities obtained in accordance with Section 6.1. Such payment shall constitute full reimbursement for all work necessary to complete the FDR base course, including watering, curing, inspection and testing assistance, and all other incidental operations.

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