Recruitment of the New LTPP SPS-10:Warm Mix Asphalt Experiment

Gabe Cimini LTPP NCRSC Project Manager

Presentation Outline

• LTPP Approach to WMA Research• Site Requirements• Roles and Responsibilities• SPS-10 Nomination Process

Why WMA?

• 356 million tons of WMA produced in 2012– 24% of all plant mix produced in US was WMA

• 35 different WMA technologies• WMA is a priority innovation under FHWA’s Every

Day Counts (EDC) Initiative

Objectives

• Long-term performance of WMA relative to HMA• Capture data on WMA with RAP

Benefits to Agencies• Detailed construction information including a

construction report• Rigorous materials testing (over multiple

intervals) using latest testing technology• Ongoing FWD, distress, profile, and texture

monitoring to study short and long term performance

• Ability to study Agency-specific issues related to WMA

SPS-10 Requirements

• Overview– AC overlay of existing AC pavements– 2” to 4” overlay thickness– Dense graded mix– RAP content 10-25% (binder replacement)– 1 HMA control test section– 2 WMA test sections

• Foaming Process• Chemical Additive

– Tack Coats between lifts

Site Layout Requirements

• WMA:– Production of ≤ 275°F or– Production at least 30°F less than HMA

Existing Pavement Requirements

• Uniformity– Subgrade type/condition– Base thickness/type– Bound layer thickness/type– Surface condition– Traffic loading– Pre-overlay repairs based on Highway Agency’s

standard practice

Experiment Layer Requirements

• Mix design/binder grade selection based on Agency’s standard practice

• Overlay thickness selected by Agency’s standard practice

• Uniformity between HMA and WMA– Same binder source/grade– Same aggregate source/gradations– Mix design/JMF

Supplemental Sections

• Agencies can build additional test sections that will be monitored as part of the LTPP program– Varying levels of RAP– Additional WMA technologies– Layer thickness variation– Open or gap graded mixtures– Varying aggregate sources/absorption levels– Other variables of interest to Agency

Roles/Responsibilities

• Agencies– Nominate project(s)– Validate in-situ conditions– Submit inventory data– Develop plans, specifications, mix design– Provide construction and

inspection/control/management – Perform materials sampling/patching– Collect traffic data– Provide traffic control

Sampling Areas (Draft)Coring at 0, 6, 12 and 18 months after construction

Traffic Data Collection Guidelines• Quality traffic data is critical in assessing the vehicle loading on

pavements– Permanently mounted sensors whenever possible– As long as a documented calibration plan is followed, data from both

portable and permanent equipment will be accepted (required LTPP Traffic Sheet 16 – Site calibration summary)

– The agency should plan to repair faulty equipment within 1 month– At a minimum, 2 weeks of continuous classification data 4 times per year

(a total of 8 weeks of classification data)– Data to be submitted by the agency on a monthly basis, however, the data

will be accepted if submitted quarterly as well – If a WMA test site does not have weight data, then the agency must

submit an LTPP Traffic Sheet 10 (Traffic volume and load estimate). Submitting 1 Sheet 10 per year is sufficient

Roles/Responsibilities• FHWA– Develop experimental

design/research plan– Coordinate among Agencies– Oversee construction data collection– Perform materials testing– Provide materials sampling support– Collect performance monitoring data– Store, analyze, and report data

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LTPP Data & Information

Climate Load

Materials

Structure

Response

Distress

Nomination Process• FHWA accepting nominations now • Projects to be constructed in 2014 and 2015• Nomination forms are available from FHWA and

the LTPP Regional Support Contractors (RSCs)• FHWA will evaluate nominations and notify

Agencies• Coordination through LTPP RSCs

Additional Tests on Materials

• Material Testing somewhat limited• Additional information beneficial on national level• Agencies encouraged to perform additional tests• Recommended by the FHWA Asphalt Mixture

Expert Task Group, based upon NCHRP Research Results Digest 370:

Additional Tests on Materials Flow Number (AMPT)

AASHTO TP 79

Hamburg TestAASHTO T 324 (Note: Prepare specimens at air voids content of 7±1% and conduct test at standard conditions: 50°C under water.)

APA AASHTO T 340Dynamic Modulus (AMPT) AASHTO PP 61Beam Fatigue AASHTO T 321

Overlay Test TxDOT Method: Tex-248-F, Test Procedure for Overlay Test, February 2014

Simplified Viscoelastic Continuum Damage (S VECD)‑ AASHTO TP 107Superpave Indirect Tension Test (IDT) University of FloridaSemi-Circular Bending Test at Intermediate Temperatures Louisiana Transportation Research Center (LTRC)IDT Creep Compliance and Strength AASHTO T 322Semi-Circular Bending Test AASHTO TP 105Disk Shaped Compact Tension – DC(T) Test ASTM D7313Moisture Sensitivity AASHTO T 283 (Note: 1 Freeze/Thaw cycle)Volumetric Properties AASHTO R 35Gyratory Compaction to Ndesign AASHTO T 312

Name Agency Phone Email

Jack Springer

FHWA-LTPP 202.493.3144 Jack.Springer@dot.gov

Gabe Cimini

North Central RSC

716.632.0804 EXT. 7470

Gabe.Cimini@stantec.com

Contact Information

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