pavement construction equipment

8/13/2019 Pavement Construction Equipment

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Dr.Eng. Trần Thị Kim Đăng

Highway Engineering 2

1. Introduction of Pavement2. Pavement Construction Materials

3. Pavement Construction Equipment

4. Unpaved Pavement Construction

5. Base and Sub-base Construction

6. Bitumen Treated Pavement Construction

7. Asphalt Mix Pavement Construction

8. Concrete Pavement Construction

9. Introduction of Pavement Maintenance

10.Road Damages and Causes

11.Road Test and Pavement Performance

12.Road Maintenance Works




Crushing and Screening Plant is an equipment to produce sound

crushed stone particles of good shape and in the sizes required for the

range of pavement making processes. It can be small scale, medium scale

and modern

Main parts of crushing and screening plant are crusher (jaw-crusher andgyratory crusher) and screens.

Crushers is an equipment to broken by crushing block stone to stone

particles. Crushing process includes primary and secondary/tertiary.

Primary stage uses jaw-crusher and following stages can use jaw, cone,

disc, gyratory, hammer or roller crushers depend nature of rocks.

Screens are used to distribute crushed stone particles in different size

required by range of pavement construction purposes




Small Crushing and Screening Plant is simple/half-motorizedequipment for local condition. It consists of a small jaw-crusher and

screens driven from a small engine through set of belts. The stone is

extracted from the quarry face and broken down by hand to be fed into the

crusher. It is collected from below the screens in wheel-barrows.

Medium Crushing and Screening Plan is motorized equipment consists

of at least two stages of crushing (primary and secondary with jaw-crusher

and gyratory crushers) and screens.

Modern Crushing and Screening Plan is motorized equipment consists

of full crushing process (primary/ secondary and tertiary) provides theneeded flexibility to alter crusher settings and screens so that the

quantities of stone of different sizes can be adjusted from time to time to

meet changes in demand


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Pavement Construction Equipment

1. Crushing and Screening Plants

2. Mixing Plants

3. Transportation Equipment

4. Compaction Equipment

5. Machinery for Earthwork

6. Machinery for Construction of Aggregate Bases

7. Machinery for Construction of Bituminous Pavement




Asphalt M ixing Plant can be batch mixing plant and drum mix plant.Batch M ixing Plant is the facility which produce asphalt mix in separate

batches. The size of batch is controlled by the capacity of pug-mill, the mixing

chamber where heated aggregates and asphalt cement are mixed. Typical batch

quantities range from about 1.5 tons to 4.5 tons.

A bath mixing plant consists of aggregate dryer, burners, screens and hot bins,weigh hopper and asphalt bucket, pug-mill mixer, air quality control system

(primary dry collector and wet collector)

Drum Mix Plant is the facility which use drum mixer to dry and heat the

aggregate economically and continuously and to mix with asphalt cement. At the

discharge end of the drum, aggregates are coated uniformly at desiredtemperature.

A drum mixer consists of aggregate feeder, drum and burners.

Mixing process in the drum mixer includes drying and heating, asphalt cement

injection, mineral filler feeding.




Aggregate dryer is a pipe facility where aggregate from cold feed enters inopposite end from the burner and flows in opposite to the direction of the exhaust

gases.

The dryer is equipped with longitudinal flights which lift the aggregates and

cascade them through the hot burner gases.

Burners is the device who burns fuel provide the heat energy for evaporating thewater from aggregate and heating them to desired temperature.

Screens and Hot Bins – screens are vibrating and for rejecting over-size

aggregate and separate aggregate into desired sizes of coarse, medium coarse,

intermediate fine and fine. Hot bins are bins for storage the 4 sized aggregate

from the screening.Weight Hopper and Asphalt Bucket – The desired amount of materials from each

bin is weighted into the weigh hopper by suspending from scales. Asphalt cement

is pumped into a weigh bucket and suspended from the scales in the same time

with aggregate (in weight hopper)




Pug-mil l mixer –

is a twin shaft mixer designed to mix the materialsufficiently to coat the aggregate with asphalt cement.

Mixing time should be as short as possible to obtain uniform asphalt

coating on all aggregate particles. Excess mixing time tends to degrade the

aggregate and oxidize asphalt cement.

Mixing process consist of dry mixing and wet mixing. Dry mixing is for

blending aggregate before asphalt binder is added. Dry mixing time is

about from 2 to 5 seconds. Wet mixing is for asphalt cement coating. Wet

mixing is started when dry mixing is completed and asphalt cement is

dropped into pug-mill. The wet mixing can last from 25 to 45 secondsdepend on size of aggregate.

After mixing, asphalt mix is dropped into a truck or temporarily stored in

a surge or storage silo.




Air Quality Control System – is required for environment protection. The

air quality control system at asphalt mixing plant includes one or more of

the three types of dust collectors: primary dry collector; wet collector or

fabric filters (bag-houses)

Primary Dry Collector – can be knockout box or centrifugal collector. It

is placed immediately at the rear of dryer. The primary dry collectors are

between 65 and 80 percent efficient and normally used with wet

scrubbers. It is operated on the principle of aggregate particle weight.

Wet collector / scrubbers –

operates on the principle that airborne dust can be forced to drop out of the airstream by increasing the particle weight by

spraying it with small droplets of water.




1. Aggregate are dried, heated, sized, and stored-in-the hot holding bin, for

proportioning according to the mixture specified.

− Individual aggregates are proportioned from the cold bins onto a single

collector belt and sent to the dryer to be dried and heated

− The dried and heated materials flow into a bucket elevator to be carried to the

top of the batch tower and deposited onto sizing screens− Multiple screen decks separate the aggregate-into different sizes and direct

the fractionated aggregate into hot bins

1. Aggregate and binder mixing

− Aggregate in each hot bin is individually weighed into the aggregate weigh

hopper until the entire batch is weighed. Separately, asphalt is weighed inasphalt weigh bucket.

− Aggregates are dropped into pug-mill and bended together (dry-mix cycle)

− Asphalt is dropped into mixer and mixed with aggregate (wet-mix cycle)




Aggregate feed includes cold feed bins and conveyers (inclined chute or slinger

conveyors).

Drum M ixer – has specified ratio of length-to-diameter. Early drum mixers used the

same ratio of 4:1 as used in batch facility dryers. Recent drums has length-to-diameter

ratio of 5:1 and 6:1 or more, due to these facilities are used for asphalt recycling

materials (RAP mixing).

Drums equip with flights which are the metal elements welded or bolted to the inside

circumference that are designed to control movement of the aggregate as they pass

through the drum

Burners – are simply devices used to efficiently burn the fuel and thereby produce

heat for the drying process. There are two types of burners, forced air burner and

hybrid type.

Asphal t Cement I njection System – is pipe system equipped at the rear of the drum

F ines Feeder System – includes pneumatic conveyor to transport mineral filler from

tank truck to a vertical silo, a vane feeders equipped at the bottom of silo, a pipe for

transport filler to the drum mixer




1 - Aggregate Drying and Heating/ M ix ing

Aggregates from cold bins are delivered to the drum. The aggregate enters the drum and

begins to move down the inclined drum by gravity. Burning flame flows oppositely from

rear of drum to dry and heat aggregate. The time the aggregate spend in the drum (dwell

time) depends on the length of drum, rotational speed of the drum, angle of drum and the

aggregate size. Typical dwell times vary from 3 to 4 minute. The aggregate temperature

profile in the drum has three distinct: drying (heated to about 380

C); drying (heated toabout 80 – 90 0C) and heating (to required mixing temperature). Dry mixing is occurred in

this stage

2 – M ixing with binder

Asphalt cement is injected into drum through a pipe entering from the rear of the drum.

Rate of asphalt spraying is controlled for coating aggregate.

3 – M ineral fi ller mixing

Mineral filler is delivered by tank truck and conveyed pneumatically to a vertical storage

silo. The filler flows out of the silo by gravity into vane feeder at the bottom of silo, then

enter the delivery pipe for transport to drum mixer and mix with asphalt coated aggregate

before being dropped into the bottom of the drum






2. Mixing Plants









1 –

Transportation operations

Transportation portion of a road construction project involves the trucks used to haul the materials

from producer to site, and the auxiliary equipment and procedures used. The procedure can be

different with different work item. In case of asphalt mix construction, the procedure includes

loading hot mix into the truck, weighing and ticketing, protecting hot mix from cooling,

transporting to the job site, dumping into the paver hopper and returning the truck to hot mix plant

2 –

Transportation equipment

Vehicles used for road construction materials transportation are commonly End Dump Trucks. The

end of dump truck is capable of lifting and rotating the truck bed to discharge materials onto

roadway or spacing hopper

There are three classes of End Dump Truck: a single unit vehicle with either a tandem rear axle or

triple rear axle; or a tractor-semitrailer with tandems on the rear of both the tractor and semitrailer

Number of trucks needed for a road construction project is affected by the length of waiting times

for loading and unloading, the loading time, time to ticket and cover the material (on the truck), the

distance between production site and the laydown site, the average truck speed and also the output

of material producer (for example of asphalt mix plant capacity and the availability of storage

facilities).




The number of tr uck-hour s requi red for hauli ng the mater ial (assumed transport distance 5 km )Activity: Crushed Stone transportation

Quantity: 1200 m3 compacted

Material is taken from stockpile prepared at the crushing plant

Productivity of the excavator for crushed aggregate loading

Unit Quantity

Bucket size m3 0.96

Bucket fill factor (% of heaped bucket capacity) for gravel % 98

Average bucket payload (ABP = 0.96m3 x 98%) m3 0.9408

Estimated time cycle sec 12

No. of cycles per 60 min hour (NC = 60min x 5 cycles/min) Cycles 120

Time efficiency factor (TF = 45 min /60 min) 0.75

Productivity (loose measure), Pl = ABP x NC x TF m3/h 84.672




The number of tr uck-hour s requi red for hauli ng the mater ial (assumed transport distance 5 km )

Unit Qty

Volume of gravel transported in 1 truck (loose measure), Vl m3 9.00

Productivity of the excavator when loading trucks (loose

measure) m3/h 84.67

Time required to load one truck, 9m3/84.67m3/h h 0.11 Time for manoeuvring at borrow pit (4 min) h 0.07

Time at dump (4 min) h 0.07

Travel time in both directions, distance 5km, speed 30 km/h

(t=10km/30km/h) h 0.33

Total cycle time for one truck, Tc=0.11+0.07+0.07+0.33 h 0.57

Number of trips per truck per hour, Nt = 1/Tc No. 1.75

Number of trips per 45 min. hour Nt' = Nt x 45/60 No. 1.31

Volume hauled per truck per hour = Vl x Nt' m3/h 11.78

Total truck hours required for the job h 122.2




Segregation –

is problem which coarse particles is segregated from fine particlesduring loading and transporting. It impacts to material grading.

Using excavator for loading and dump truck for transporting are key factors to avoid

segregation, water or suitable product spraying into materials is one method used to

limit segregation.

While single dump loading produces segregation around all edges of the truck bed,multiple dump loading can minimize segregated area within the truck bed.

Protection dur ing haul – there should have methods to protect materials from loss

and/or quality reduction during haul from production site to laydown site. A

protective covering should be used to prevent loss of loose material during wind or

cooling of hot mix asphalt.

For asphalt mix transporting, the truck bed should be cleaned and coated with a

lubricant to prevent sticking. The covers for hot asphalt mix should lap over the sides

of the truck bed and be snugly tied down all along sides and rear of the truck bed.






2. Mixing Plants









TYPE OF COMPACTION EQUIPEMNT

Roller - grid roller; steel-wheeled roller; pneumatic-tired roller; vibratorysteel-wheeled roller

Compactor - hand rammer; vibrating rammer (vibrating plate compactor);

vibrating stick compactor

Steel – Wheeled Roll er – these rollers typically are of the tandem and three-wheel types

and come in variety of weights and configurations. Tandem steel-wheeled rollers havetwo axle with both drums in the same width. Many of these rollers have a single drive

drum to propel the machine. The drive drum is often larger than steering drum. This roller

is typically used as a breakdown roller during the initial part of rolling operation.

Pneumatic- Tir ed Rollers – can be called either rubber-tired roller with the tires designed

for kneading action. Typical configurations of pneumatic-tired rollers provide 4,5,6 or 7

tires on the front of the roller and 3,4,5 or 6 tires on the rear. PTR can be used in the breakdown or intermediate roller positions.

Vibratory Steel-Wheeled Roller – five types of vibrating rollers: Single drum – rigid

frame; Single drum – articulated frame; Double drum – rigid frame; Double drum – single

– articulated frame; Double drum – double articulated frame




KOMATSU JV100A VIBRATION ROLLER

1. Steering wheel2. Rear wheel

3. Scraper

4. Front wheel (vibratory roller)




TYPES OF MATERIALS AND

RECOMMENDED COMPACTORS

Types of Soil/ Compactors

S t e e l R o

l l e r

T i r e d R

o l l e r

T a m p i n

g R o l l e r

V i b r a t i o n R o l l e r

V i b r a t i o n C o m p a c t o r

R a m m e

r / T a m p e r

G r i d R o

l l e r

B u l l d o s e r

S w a m p

B u l l d o s e r

Rock xx xx xxx xx xx

Coarse grained sand xx xx xx

Sand, Sandy soil xxx xx xx xx xx xx xx

Clayey gravel, Cohesive soil xx xxx xx xxx

Soft clay xx xx xx

Asphalt Mix xxx xxx xx xx






2. Mixing Plants









ROLE AND ADVANTAGES OF USING

MACHINE FOR EARTHWORK

The roles of construction mechanization:

• Capacity to carry out big scale work

• Decreasing the construction cost

• Shortening the construction time

• To uniform the quality of construction

Advantages of mechanization :

•Ability to carry larger scale operations

• Reduce working time

• Encourage uniformity

• Establish larger operating unit

• Reduced manpower

• Relief from heavy manual or exhausting work

• Improve operating safety

Disadvantages of mechanization:

• Large capital needed for obtaining equipment

• Increase management work for equipment

• Need training on machines operation and management




EQUIPMENT SELECTION FOR EARTHWORK

Work Items Equipment Clearing Bulldozer, Rake dozes, Backhoe

Excavating Power shovel ( Backhoe, Draggling, Clamshell), Bulldozer,

Ripper, Rock breaker

Loading Power shovel (Backhoe, Draggling, Clamshell), Tractor

shovel

Excavating/Loading Power shovel (Backhoe, Draggling, Clamshell)

Excavating/Hauling Bulldozer, Scrape dozes, Scraper dozes

Hauling Bulldozer, Dumbslruck, Conveyer

Spreading and Grading Motor grader, bulldozer, Tire dozes

Compacting Tire roller, Steel roller, Vibration roller, Tamping roller,

Vibration compactor, Tamper, Bulldozer.Trenching Trencher, Backhoe

Aggregate Base/Subbase Motor grader/ Paver

Slope Finishing Backhoe, Motor grader

Rock Braking Drill, Rock Breaker




WORK TYPES AND EQUIPMENT COMBINATION

Work Items Equipment

Clearing/loading/ Hauling Bulldozer +Tractor shovel +Dump truck(or Backhoe)

Excavating/Loading/Hauling Bulldozer +Loading equipment +Dump truck

Excavating - Loading/Hauling -

Spreading

Scraper +Pusher




TYPES OF SOIL AND RECOMMENDED

CONSTRUCTION MACHINES

Types of Soil Equipments

Sand, Sandy soil Wheel type or crawler type tractor shovel for

loose soil

Power shovel Bulldozer for natural density

Clay, Cohesive soil Power shovel

Soft rock Bulldozer with ripper, Rock breaker

Hard rock Large size bulldozer with ripper, rock breaker




TYPICAL EARTHWORK MACHINE AND CRITERIA

Types of Equipment Major Criteria Bulldozer Normal Working Condition - 11,15 ,21, 32 (ton)

Swamp - 13, 16 (ton)

Bulldozer with ripper Normal Working Condition - 21, 32 (ton)

Scrape doze Normal Working Condition - 6.4 (m3)

Tractor-pulled scrapper 9, 12, 17 (m3)

Molor scraper Single engine - 16 (m3)

Backhoe (hydraulic type) Crawler - 0.35; 0.4; 0.6; 0.7 (m3)

Draggling and Crashed Mech. Crawler 0.8 (m3)

Hyd. Crawler 0.3, 0.6 (m3)

Tractor shovel Crawler 0.4, 1.8 (m3)

Wheel 1.0, 1.4, 2.3 (m3)

Dump truck 1, 10-11 (ton)




BULLDOZER - KOMATSU D65E




EXCAVATOR CATERPILLAR 31,I8




MITSUBISHI MG330 MOTOR GRADER




HAULING DISTANCE AND CONSTRUCTION

EQUIPMENT UNIT COST

D1 - Max. Advantageous Hauling Distance for bulldozer

to motor scraper.

D2: Max, Advantageous Hauling Distance for bulldozer

to Shovel Dump Truck

D3: Max. Advantageous Hauling Distance for Tractor-

drawn Scraper




CONSTRUCTION EQUIPMENT SELECTION

Equipment Optimum Hauling Distance

Bulldozer Less than ) 60 m

Scrape dozes 40-250 m

Tractor-drawn Scraper 60-400 m

Motor Scraper 200-1200 m

Shovel- Dump Truck more than 1000 m

Optimum haul ing distance:

Balance abili ty of construction machine :

Equipment Slope

Swamp Buildozer 40-45

Buildozer 35-40

Tractor-pulled scraper 15-25

Motor scraper =10

Dump Truck = 10






2. Mixing Plants









MACHINES USED FOR BASE/SUB-BASE

CONSTRUCTION

Base/Sub-base construction process

• Site preparation/ material preparation: re-compaction (rollers) / re-

grading (grader) – material production – crushing/screening plant

• Material transportation/ hauling – dump truck

• Material spreading/paving: graders/ paver

• Compacting: steel roller/ vibrating steel roller/ pneumatic tired

roller






2. Mixing Plants









MACHINES USED FOR BITUMINOUS PAVEMENT

Bitumen treatment pavement construction process

• Asphalt/ binder distributor

• Aggregate/chipping spreader

• Slurry mixer/spreader

• Compaction

Asphal t pavement construction process

•

Prime coat/ Tack coat• Asphalt mix paver

• Compaction





Asphalt distr ibutors:

- Pressur ized tank distr ibutor : an air compressor is used to generate a constant high air

pressure in the tank thereby delivering the binder at constant pressure to the spray bar(jets) at the rear of the machine. The jets under controlled pressure deliver a constant

volume ol binder in unit time and the rate of spread of binder is controlled by the

forward speed of the vehicle.

- Constant rate of spread distr ibutor: - similar with pressurized tank distributor with

metering pump driven front the main transmission of the vehicle through a multi-ratiogear box

- Constant volume binder distr ibutor: binder is delivered to the spray bar through

positive displacement pumps. The output binder can be adjusted. Spray width can be

adjusted by additional extensions to the spray bar with appropriate adjustments to the

pumps.

- Constant pressure binder distributor: use pumps to generate adequate pressure and this

pressure is controlled by a valve mounted in the spray bar which permits binder to

bypass the spray bar and return to the tank. Then constant pressure is maintained in the

spray bar. The rate of spread of binder is controlled by the forward speed of the machine.






Asphalt distr ibutors: - Constant Pressure Bitumen Distr ibutor






Chippings spreader:

The simplest chipping spreaders are tailgate attachments fitted to the

rear-of the trucks used to haul the chippings to the site. A further

elaboration involves the use of a wheeled hopper with a metering roller

which is pushed by the reversing truck with chippings loaded in thehopper.

Slur ry mixer and spreader/ micro paving :

Fine-graded aggregate is mixed with bitumen emulsion at ambient

temperatures to produce a slurry which can be spread over the surface

in a thin layer.

A MOBILE SLURRY MIXER AND SPREADER




A MOBILE SLURRY MIXER AND SPREADER

ASPHALT MIX PAVER




ASPHALT MIX PAVER

ASPHALT MIX PAVER




ASPHALT MIX PAVER

COMPONENTS OF ASPHALT MIX PAVER





Hopper - The hopper is the area where the HMA is deposited by the hauling unit, pickupmachines, or material transfer device.

Hopper insert -The hopper insert is a metal bin inserted inside the paver hopper to

receive material from the truck to expand the hopper storage capacity by 50 to 70 percent

Push rollers - These rollers mounted on the front of the paver push on the hauling unit

tires as the HMA is being transfered from the hauling unit to the paver hopper.

Slat conveyer - The slat conveyer is the mechanism used to move tire HMA from the

hopper to the augers in front of the screed. The conveyor is connected at both ends to two

parallel chains that pull the mix from the hopper.

F low Control gates - These adjustable metal plates change the size of the opening at

hopper discharge used to control the amount of material flowing out of the hopper.

Tow point - This point near the center of the paver where the side arms are attached is a

pivoting connection that allows the side arms to rotate around this point.





Side arms - The side arms connect the screed to the tow point on the tractor and are

responsible for towing the screed.

Auger - The augers receive the material from the slat conveyers, moving it transversely

and uniformly across the full width of the screed.

Screed - The screed is the most important component of the asphalt paver. It is

essentially a wide flat piece of heated steel that knocks down and smooth out the mass of

material placed in front of it by the augers. In doing so, it places the material to the

proper grade cross slope, and texture and provides initial compaction of the HMA. The

use of screed extension allows paving widths wider than the basic screed provides.

Depth-Screws . These manually operated screw mechanism change the angle of the

screed plate as it passes through the HMA material, allowing more or less material to pass under the creed. The careful control of .this angle, also known as angle of attack,

precisely controls the thickness of the mat being placed.

pavement construction equipment

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