NATIONAL ROAD IMPROVEMENT AND MANAGEMENT PROGRAM 2 (NRIM 2)
IMPROVEMENT OF MINDORO EAST COAST ROAD
CP-RI-2.2: BONGABONG BYPASS, DANGAY JNCT. – ROXAS – MANSALAY SECTION
METHOD OF STATEMENT
SURFACE COURSES
PORTLAND CEMENT CONCRETE PAVEMENT:
1.0 Equipment & Minor Tools:
Concrete Batching Plant
Volumetric Type Concrete Batching
1. Crane with Concrete Bucket-1 unit
2. Transit Mixers-2 units
3. Backhoe-1unit
4. Concrete Vibratory Screeder-1unit
5. Concrete Vibrator-2 units
6. Boom Truck-1 unit
7. Service Vehicle-1
8. Stake/Boom Truck - 1 unit
9. Water Truck – 1 unit
10. Transit Mixers – 6 units
11. 1- Bagger Mixer – 1-unit
12. Concrete Vibratory Screeder - 1 unit
13. Paint Brush 100 mm. width – 4 pcs.
14. Nylon String # 8 – 200.0m
15. Manual Screeder (50mm x150mm x 4.5m.) - 1 unit
16. Concrete Vibrators - 2 units
17. Concrete Cutter with spare blades & fan belt - 1 unit
18. Floats (12mm. x 100mm. x 1200mm.) with handle - 2 units
19. Hand Trowels – 4 pcs.
20. Brooming/Grooving tool (200mm. width) with handle - 2 units
21. Curing Compound Sprayers - 2- units
22. Plastic Pails – 4 pcs.
23. Empty Drums – 4 pcs.
24. Electric Drill -1 unit
25. Edgers/Choppers -4 units
26. Brooms sticks (coco sticks) – 4 pcs.
27. Spade Shovels – 8 pcs.
28. Rakes – 2 pcs.
29. Crow Bars – 4 pcs.
30. Flat Bar with handle sharpened at tip edge – 4 pcs.
31. Bulk Hammer 4 ounce – 4 pcs.
32. Generator Set with at least 4-lightings – 1 unit
33. Asphalt Kettle (20 liters capacity)– 2 pcs.
34. Movable Steel Shade Frame – optional ( necessary during rainy days)
Materials Required:
1. PCCP Concrete – at required quantity
2. Steel Forms 3.0m. length – at least 70 pcs.
3. Steel spikes 12mm Ø x 0.60m – 420 pcs.
4. Curing Compound – 100 liters
5. Portland Cement – 10 Bags
6. Coarse & Fine Aggregates in sacks – as required quantity
7. Asphalt Sealant – 2 pails
8. Epoxy (Hardener & Adhesive) – 1 set
9. Used Oil - as required quantity
10. Cementitious Grout – 1 bag
11. Canvass Sheets – 200.0m. length
12. Tie Wire # 16 - as required quantity
Manpower:
1. Site Engineer-1
2. Foreman-1
3. Surveyor-1
4. Safety Officer-1
5. Instrumentman-1
6. Materials Engineer-1
7. Laboratory Technicians-2
8. Survey Aides-4
9. Laboratory Aides-2
10. Service Driver-1
11. Crane Operator-1
12. Transit Mixer Drivers-2
13. Backhoe Operator-1
14. Boom Truck Driver-1
15. Service Driver-1
16. Concrete Screeder Operator-2
17. Concrete Cutter Operator-1
18. Traffic Aides/Flagmen-4
19. Floaters-2
20. Carpenters-6
21. Mason-4
22. Unskilled Laborers-8
23. Security Guards-2
24. Watchmen-2
2.0 Materials Requirements:
Portland Cement shall conform to the applicable requirements of Item 700, Hydraulic
Cement. Only Type I Portland Cement shall be used unless otherwise provided for in the
Special Provisions. Cement which contains caked cement and salvaged from discarded or
used bags shall be rejected.
Samples of cement shall be obtained in accordance with AASHTO T 127.
Fine aggregate shall consist of natural sand, stone screenings or other inert materials
with similar characteristics, or combinations thereof, having hard, strong and durable particles.
Fine aggregate from different sources of supply shall not be mixed or stored in the same pile
nor used alternately in the same class of concrete without the approval of the Engineer.
The fine aggregate shall not contain more than three (3) mass percent of material
passing the 0.075 mm (No. 200 sieve) by washing nor more than one (1) mass percent each of
clay lumps or shale. The use of beach sand will not be allowed without the approval of the
Engineer.
If the fine aggregate is subjected to five (5) cycles of the sodium sulfate soundness test,
the weighted loss shall not exceed 10 mass percent.
The fine aggregate shall be free from injurious amounts of organic impurities. If
subjected to the colorimatic test for organic impurities and a color darker than the standard is
produced, it shall be rejected. However, when tested for the effect of organic impurities of
strength of mortar by AASHTO T 71, the fine aggregate may be used if the relative strength at
7 and 28 days is not less than 95 mass percent.
The fine aggregate shall be well-graded from coarse to fine and shall conform to the
Grading Requirements specified in Table 311.1 of 2004 DPWH Standard Specification for
Highways, Bridges and Airports.
Coarse aggregate shall consist of crushed stone, gravel, blast furnace slag, or other
approved inert materials of similar characteristics, or combinations thereof, having hard,
strong, durable pieces and free from any adherent coatings.
The coarse aggregate shall contain not more than one (1) mass percent of material
passing the 0.075 mm (No. 200) sieve, not more than 0.25 mass percent of clay lumps, nor
more than 3.5 mass percent of soft fragments.
If the coarse aggregate is subjected to five (5) cycles of the sodium sulfate soundness
test, the weighted loss shall not exceed 12 mass percent.
The coarse aggregate shall have a mass percent of wear not exceeding 40 when tested
by AASHTO T 96.
If the slag is used, its density shall not be less than 1,120 kg/m3 (70 lb./cu. ft.). The
Grading Requirement of the Coarse Aggregate shall conform to Table 311.2, Grading C of
2004 DPWH Standard Specification for Highways, Bridges and Airports.
Only one grading specification shall be used from any one source
Water used in mixing, curing or other designated application shall be clean and free
from oil, salt, acid, alkali, grass or other substances injurious to the finished product. Water
shall be tested in accordance with and shall meet the requirements of Item 714, Water.
Potable water which is drinkable may be used without test.
Reinforcing Steel shall conform to the requirements of Item 404, Reinforcing Steel.
Dowels and tie bars shall conform to the requirements of AASHTO M 31 or M 42. Tie bars
shall be deformed bars. Dowels shall be Plain Round bars. Before delivery to the site of work,
one-half of the length of each dowel shall be painted with one coat of approved lead or tar
paint.
The pipe sleeves for dowel bars shall be metal of approved design to cover 50 mm ( 2
inches), plus or minus 5 mm (1/4 inch) of the dowel, with a closed end, and with a suitable
stopper to hold the end of the sleeve at least 25 mm (1 inch) from the end of the dowel. Pipe
sleeves shall be of such design that they do not collapse during construction.
Poured Joint Fillers shall be mixed Asphalt and Mineral or Rubber Filler conforming to
the applicable requirements of Item 705, Joint Materials.
Preformed Joint Filler shall conform to the applicable requirements of Item 705. It shall
be punched hole to admit the dowels where called for in the Plans. The Filler for each joint
shall be furnished in a single piece for the full depth and width required for the joint.
Air-entraining Admixture shall conform to the requirements of AASHTO M 154.
Chemical Admixtures, if specified or permitted, shall conform to the requirements of AASHTO
M 194.
Fly Ash, if specified or permitted as a Mineral Admixture and as 20% partial
replacement of Portland Cement in Concrete Mix shall conform to the requirements of ASTM C
618.
Admixture should be added only to the Concrete Mix to produce some desired
modifications to the properties of concrete where necessary, but not as partial replacement of
cement.
Concrete Curing materials shall conform to the following requirements as specified;
a) Burlap cloth - AASHTO M 182
b) Liquid membrane forming Curing Compounds - AASHTO M 148
c) Sheeting (film) materials - AASHTO M 171
d) Cotton mats and water-proof paper can be used.
Calcium Chloride/Calcium Nitrate shall conform to AASHTO M 144, if specified or
permitted by the Engineer, as Accelerator.
Portland Cement and Aggregate shall be stored, immediately upon delivery at the Site,
in weatherproof building which will protect the cement from dampness. The floor shall be
raised from the ground. Provisions for storage shall be ample, and the shipments of cement as
received shall be separately stored in such a manner as to allow the earliest deliveries to be
used first and to provide easy access for identification and inspection of each shipment.
Storage buildings shall have capacity for storage of a sufficient quantity of cement to allow
sampling at least twelve (12) days before the cement is to be used. Bulk cement, if used, shall
be transferred to elevated air tight and weatherproof bins. Stored cement shall meet the test
requirements at any time after storage when retest is ordered by the Engineer. At the time of
use, all cement shall be free-flowing and free of lumps.
The handling and storing of concrete aggregates shall be such as to prevent
segregation or the inclusion of foreign materials. The aggregates shall be required to be
stored on separate platforms of satisfactory locations. In order to secure greater uniformity of
concrete mix, it is required that the coarse aggregate shall be separated into two or more
sizes. Different sizes of aggregates shall be stored in separate bins or in separate stockpiles
sufficiently removed from each other to prevent the material at the edges of the piles from
becoming intermixed.
3.0 Proportioning, Consistency and Strength of Concrete:
The Contractor shall prepare the Concrete Design Mix based on the Absolute Volume
Method specified in the American Concrete Institute (ACI) Standard 211.1, “Recommended
Practice for Selecting Proportions for Normal and Heavyweight Concrete”.
It is the intent of this Specification to require at least 364 kg of cement per cubic meter
of concrete to meet the minimum strength requirements. The Engineer shall determine from
laboratory tests of the materials to be used, the cement content and the proportions of
aggregate and water that will produce workable concrete having a slump of between 40 and 75
mm (1-1/2 and 3 inches) if not vibrated or between 10 and 40 mm (1/2 and 1-1/2 inches) if
vibrated, and a flexural strength of not less than 3.8 MPa (550 psi) when tested by the third-
point method or 4.5 MPa (650 psi) when tested by the mid-point method at fourteen (14) days
in accordance with AASHTO T97 and T177, respectively; or a compressive strength of 24.1
MPa (3500 psi) for cores taken at Fourteen (14) days and tested in accordance with AASHTO
T24.
Slump shall be determined in accordance with AASHTO T 119.
The Concrete Mix Design shall be submitted to the Engineer for approval with attached
certified test data from an accredited laboratory by DPWH demonstrating the adequacy of the
Mix Design. A change in the source of materials during the progress of the work may
necessitate a new Design Mix.
4.0 Procedures:
Methodology:
Upon complying the Survey lines and grades checking jointly with the Engineer’s
Surveyor, checked and inspected by the Engineer and complied and approved the test
required for the Aggregate Sub-base preparation, PCCP concrete batching may proceed or as
directed by the Engineer.
The PCCP preparation shall be done at phases of every Ninety (90) meters at end to
end of Expansion Joints at staggered spaces, to minimize long queue of traffic.
1ST Stage: Establish Alignment & Elevation Control
Establish centerline at every 5.0m by driving firmly on the prepared base 12mm Ø x
0.60m. deformed steel spikes and at the edges of PCCP width according to plan to be carried
out by the Survey Group.
Tie a string line on the driven spikes along the centerline and at PCCP edges to counter
check the true alignment and properly check the steel spikes alignment. Ensure that the outer
edge of the spikes serves as the guide for the centerline control.
Establish PCCP finished grade line by marking on the steel spikes by the Survey Group.
Fix tied the string line at every driven spikes on the marked PCCP grade line.
2nd Stage: PCCP Steel Form Setting
Inspect properly each Steel forms should there are any deformed face or misaligned,
especially its horizontal and vertical straightness, free from concrete adhering on the forms
faces before finally setting the forms.
Set the steel forms at both sides, that the forms are placed at the outer side of the
spikes. Properly fix the steel forms rigidly by driving spikes thru the holes and outer diagonal
spike braces at intervals of 1.0m.
Fix tie wired the horizontal spikes with the diagonal braces.
Adjust the forms to meet the required marked finished grade line on the spikes.
After setting and fixed the steel forms according to alignment and finished grade line.
Check properly the rigidity of the horizontal and diagonal braces by applying slight
pressure by foot on the steel forms. If there are any movements, fix the braces to
ensure that the forms shall not deflect.
After the forms were properly and rigidly set, apply used oil on its faces simultaneously to
avoid the concrete adhering to the steel forms that normally caused difficulty during removal of
the steel forms.
Dowels at longitudinal joints shall be installed in accordance with the required size,
spacing and length in the plan.
Clean thoroughly the adjoining existing or newly constructed concrete pavement and
apply cement mortar on its surface during pouring. Drill holes, apply epoxy and provide dowels
on the adjoining existing concrete pavement as required.
Final elevation and alignment checking shall be jointly conducted by the Consultant’s
and the Contractor’s Surveyor and follows the Field Density Test by the Materials testing crew,
before scheduling the time of concrete pouring.
3rd Stage: During Concrete Pouring
Positioning of the Transit Mixers may be done along the side or right within the prepared
area for directly pouring the fresh concrete.
Before placing the fresh concrete, moistened first the prepared surface by sprinkling
water from the Water Truck.
Pour the fresh concrete evenly on the prepared surface and make adjustments by initial
levelling manually, provided that the personnel wear a pair of rubber boots when stepping into
the newly in-placed fresh concrete. The rubber boots shall not be contaminated or coated with
earth or foreign materials.
The height of the Transit Mixer’s chute to discharge the fresh concrete shall not be
more than 1200mm from the prepared surface to avoid segregation of the coarse aggregate of
the concrete mixture.
When concrete is to be placed adjoining a previously constructed lane and mechanical
equipment will be operated on it, that previously constructed lane must have attained the
strength for Fourteen (14) days concrete. If only finishing light equipment is carried on that
lane, concrete paving in adjoining lanes may be permitted after three (3) days.
Consolidate the concrete by vibrator at specified uniform and minimum spaces (ideal
spaced at 450mm.) in introducing the vibrating rod into the newly placed concrete. In no case
shall the vibrator be operated longer than Fifteen (15) seconds in any one location.
The vibrating rod shall be maintained vertically in position.
Strictly do not lay down the vibrating rod freely vibrating into the concrete mix. Do not
repeat vibrating the completed portion.
Strike or level the concrete by first using the vibratory screeder and followed by a
manual concrete screeder for fine corrections.
Trowel the concrete surface by a hand float tool and remove excess water to the edges.
While the concrete initially hardened, chamfer roundly the edges by using an edger or chopper
tool. The edge’s radius shall be that specified in the plan.
While the concrete is partially finished, immediate corrections shall be done before it will
finally hardened.
Make always ready at pouring site at least 4 drums filled with water to be used for
cleaning/washing the floats, trowels, edgers/choppers and other tools.
Take consideration on the condition of the concrete before final setting and finished the
surface by broom/grooving tool, perpendicular to the centerline that the groove’s spacing is in
accordance with the plan.
Apply curing compound timely according to number of application recommended by the
Manufacturer and the Specification requirements.
Provide at all times canvass/plastic sheets to cover the finished concrete pavement, to
prevent early dehydration of the concrete and for covering freshly poured concrete whenever
heavy rain occur.
Before scheduling the concrete pouring, all the required equipment, minor tools and
materials shall be always made ready at site.
4th Stage: After Completion of Concrete Pouring
Maintain cover with canvass sheet after the final setting of the concrete pavement at
least 24.0 hours to prevent early dehydration of the concrete caused by shrinkage/temperature
cracks.
Ensure that new pavement is properly covered and canvass sheet is properly fixed so
that it would not be blown out by strong wind.
Cordon the finished concrete pavement area and provide barricades to prevent
accidental entries of pedestrians, bicycles, motorcycles, cars, etc. and intentionally entry of
animal monkey peoples stepping on the concrete.
Assign and post watchmen to secure the area and provide sufficient lightings.
Monitor and record the timing sequences of placing the concrete from the Transit Mixers
as basis for estimating the number of hours the concrete had set.
Take into consideration that the newly poured concrete pavement is expectedly and
theoretically will crack at the intervals of the weakened plane joints locations, due to
delayed cutting. Therefore, cutting timing must not be delayed to avoid occurrences of
cracking in the newly completed concrete pavement.
The weakened plane joint shall be perpendicular to the pavement’s centerline.
Before cutting, the perpendicularity of the weakened plane joint line to the centerline
shall be properly laid out first and checked to avoid error or misalignment.
At least a minimum of 4.0 hours, but not later than 24.0 hours shall the weakened plane
joints location be strictly sawed cut in accordance with the plan dimensions of 6mm in width
and a depth of 50mm, to prevent the expected cracking.
Before applying the hot Asphalt Sealant into the sawed joints, it shall be thoroughly
cleaned by removing manually the cement dusts or sand or by using an air compressor
machine with pressurized water jet and let dry.
The pavement shall not be allowed to be opened to traffic, unless it complied the
required curing period at 14 days, passed the compressive/flexular strength requirements
according to Specification, completely applied with an Asphalt Sealant to all longitudinal,
transverse, weakened plane and expansion joints and upon approval by the Engineer.
Concrete pouring for PCCP shall commence after the Aggregate Sub-base preparation
has been done and checked according to the designed lines and grade and the compaction
requirements of the Standard Specification. The area to be poured shall be uniformly moist by
spraying water before placing the fresh concrete. The fresh concrete shall be transported to
the site by Transit Mixers and directly discharge to the pouring site. Suitable paving equipment
a Concrete Paver Finisher to spread the concrete shall be used to attain quality workmanship.
However, on sections where Concrete Finisher is not applicable especially on shorter
lengths and in reblocking, Manual Vibratory Concrete Screeder shall be applicable. The
concrete shall be consolidated against along the faces and the full length of the forms at both
sides of all joints by means of concrete vibrators effected on the concrete.
Forms shall be rigidly supported on the prepared surface of thoroughly compacted
material during the entire operation of placing and finishing the concrete. It shall be set with its
faces vertical to produce a surface complying with the tolerance requirements. The steel forms
shall be applied with used oil by using hand brush to prevent the concrete to adhere on the
form during removal of the forms. Adjacent lanes shall be used in lieu of forms to support the
finishing requirement.
Portland Cement Concrete shall be batch at the area where the Concrete Batching
Plant is installed. Course and fine aggregate shall be stockpiled near the Concrete Batch
Plant.
Prior to PCCP concreting operations, a Trial Mix Design shall be submitted for approval
by the Engineer’s Representative including the grading requirements. Upon approval of the
Design Mix, it shall be used to carry out the operations in the Concrete Batch Plant.
The concrete shall be deposited and spread in such a manner that segregation will not
occur. Provide Expansion Joint Filler, dowels at specified reinforcing bar size and spacing with
capped PVC pipe sleeves at Expansion Joints at intervals specified in the approved plan.
Provide also dowels at longitudinal and construction joints at specified reinforcing bar size and
spacing in accordance with the plan. The personnel shall confine their movements to the area
covered with fresh concrete. Workers on the job shall provide mobile footbridge to avoid
directly stepping into the fresh concrete. In case rain occurred during concrete pouring
operation, sufficient canvass sheet shall be provided to cover and protect the fresh concrete.
Forms shall remain in place at least 12 hours after pouring the concrete. Any damage
as a result of removing the forms shall be repaired immediately. The use of curing compound
approved by the Engineer shall be the method of curing the concrete. This shall be sprayed on
the surface of the finished concrete at the time when it is about to dry, in such a way that two
thin layers (spraying) of this curing material shall be maintained throughout the whole area of
the finished concrete.
After the required curing period where the Flexural Test passed in accordance with the
Standard Specification and before opening the pavement to traffic, all joints shall be thoroughly
cleaned of all concrete dusts or aggregate figments. Care must be considered so as not to
inquire the ends of the joints that caused spalling. Joints shall be poured with an approved
Asphalt Sealant by using hand pouring pots at a temperature not less than that recommended
by the Manufacturer.
Cement Concrete Pavement shall be opened to traffic at least 14 days after the
concrete is placed or longer if in the opinion of the Engineer’s Representative where weather
conditions makes it necessary to extend the time. During the curing period, where the
pavement is not yet opened to traffic, satisfactory barricades, lights and caution signs shall be
provided and maintained. Any damage that may occur during this curing period to the
pavement shall be repaired or replaced immediately.
BITUMINOUS CONCRETE SURFACE COURSE:
1.0 Equipment:
1. Asphalt Concrete Batch Plant-1 unit
2. Asphalt Concrete Paver-1 unit
3. Asphalt Distributor-1 unit
4. Dump Trucks-6 unit
5. Vibratory Tandem Roller-1 unit
6. Pneumatic Roller-1
7. Water TankTruck-1 unit
8. Stake Truck-1 unit
9. Service Vehicle-1
2.0 Manpower:
1.0 Site Engineer-1
2.0 Asphalt Concrete Batch Plant Operator-1
3.0 Asst. ACBP Operator-1
4.0 ACBP Helpers-6
5.0 Asphalting Foreman-1
6.0 Asphalt Paver Operator-1
7.0 Screederman-1
8.0 Asphalting Helpers-8
9.0 Surveyor-1
10.0 Instrumentman-1
11.0 Survey Aides-4
12.0 Safety & Traffic Officer-1
13.0 Materials Engineer-1
14.0 Laboratory Technicians-2
15.0 Laboratory Aides-2
16.0 Asphalt Distributor Driver-1
17.0 Dump Truck Drivers-6
18.0 Vibratory Tandem Roller Operator-2
19.0 Pneumatic Roller Operator-1
20.0 Water Truck Driver-1
21.0 Stake Truck Driver-1
22.0 Service Vehicle Driver-1
23.0 Traffic Aides/Flagmen-4
24.0 Security Guards-2
25.0 Watchmen-2
3.0 Material Requirements:
The kind of Bituminous material to be used shall be Modified Bitumen Penetration
Grade 50-70 and conform to the requirements of Item 702, Bituminous Materials.
The aggregates for the Premixed Bituminous layers shall be obtained from an approved
source and consists of clean, hard, heavy, compact and sound particles free of faulty flaky,
elongated, soft or decomposed materials, vegetable matter and other deleterious
substances.
Coarse aggregate retained on a 4.75mm (No. 4) sieve, shall consists crushed river
gravel and a particle size is at least Three (3) times as large as the maximum size of the
final product.
Fine aggregate passing 4.75mm (No. 4) sieve , shall consist of sand or stone screening
or a mixture thereof. At least 50% by weight of the fine aggregates shall be angular or
fractured particles.
In addition to the General Requirements, the aggregate shall meet the following:
a. The percentage of wear by Los Angeles Abrasion test (AASHTO T96) shall not be more
than the value 35%.
b. When tested for Sodium Sulfate Soundness (AASHTO T104) the loss shall not be
greater than 12% after 5 cycles.
c. The Sand Equivalent (AASHTO T176) shall not be less than 45.
d. The flakiness index of aggregate retained on the 9.5mm (3/8 in.) sieve when tested in
accordance with abs 812 shall not exceed 35%. (The Flakiness Index of an aggregate
is the percentage by weight of particles whose least dimension (thickness) is less than
three fifths of their mean dimension. The test is not applicable to material passing
6.3mm (1/4 in.) sieve.
e. All aggregate shall be non- plastic.
The combined aggregate grading shall conform to the Gradation specified in Table 310.1,
Grading D of Section VI. Works Requirements.
When the combined grading of aggregates is deficient in material passing the No. 200
sieve, additional filler material shall be added. However, the aggregate shall be adjusted to
take into account the results of the Trial Mix, to allow the Asphaltic Concrete Mix to conform to
all the requirements of the specified Job Mix.
Mineral Filler shall consist of finely divided, rock, dust, hydrated lime, Portland Cement or
other suitable mineral matter and shall conform to the grading requirement specified in Table
310.2, Section VI of Works Requirements.
Hydrated Lime to be used shall conform with Item 701, Construction Lime.
The Bitumen content shall conform to the requirements specified in Table 310..3.
However, the exact composition of the mixture shall be adjusted to take into account the
results of the Trial Mix.
Marshall Specimens are to be obtained from the Bituminous Course material supplied
for the trial laying purposes. The Marshall specimens be formed and compacted in proper
molds, in accordance with procedures described in AASHTO T245.
The Contractor shall carry out the testing in the presence of the Engineer, to
demonstrate to the satisfaction of the Engineer, in accordance with procedures set out in the
Marshall Method of Mix Design in the Asphalt Institute Manual, Mix Design Methods for
Asphalt Concrete and other Hot Mix Types, Manual Series No.2 (MS-2), the requirements
given in Table 310.4 are achieved. The Loss in Marshall Stability by submerging the
specimens in water at 60̊C for 24 hours shall not be more than 25% of the stability of the Job
Mix.
To determine the Marshall specimen’s density from each set of Six Marshall specimen,
the highest and lowest densities shall be discarded and the Marshall specimen shall then be
the mean of the densities of the remaining four specimens. Testing shall be in accordance with
ASTM D1168 or ASTM D2726.
Bituminous Plant Mix shall not be placed on any wet surface or when weather
conditions would prevent the proper handling or finishing of the Bituminous Mixtures.
For general Asphalt Overlay, the Ready Mixed Hot Asphalt shall be delivered by Dump
Trucks, discharged into the Asphalt Paver’s hopper and spread by itself. Immediately, after the
Pre-Mix Hot Asphalt has been spread, the surface shall be dragged or bladed to fill the ruts
and adjust surface irregularities. Immediately, the Pre-Mix Hot Asphalt shall be rolled before its
temperature has fallen below 130̊C. Firstly, 3-4 tons Steel Wheel Rollers to compact the
Asphalt for 4 passes. Then follows by another 2 passes using 6-8 tons Steel Wheeled Rollers
to finish off the compaction. Pneumatic Rollers shall not be used.
Rolling shall be continued until all roller marks are eliminated and a density of at least
96% of the maximum density achieved during the Job-Mix Formula determination has been
attained.
Rolling shall begin at sides and proceeds longitudinally parallel with the road’s center
line, overlapping on successive passes at least one half the roller width and gradually
progressing to the crown of the road. When paving abutting previously placed lane, the
longitudinal joint shall be rolled first followed by regular rolling procedure. On super-elevated
sections, compaction shall begin from the lower edge and progresses to the higher edge,
overlapping longitudinal passes parallel with the center line. Transverse and longitudinal joints
shall be formed by cutting back on the previous placed lane to expose the full depth of the
course. It shall be brushed coat with Asphaltic Material before placing additional mixture
against the previously rolled material. Rolling shall continue until the surface is in uniform
texture. When excessive pulverizing of aggregate or displacement of the mixture is observed,
rolling shall be discontinued.
The allowable tolerances for Flexible Surfacing are specified in Table 310.5
Core sampling and testing shall be carried out at a minimum of rate of 1 test for each
100 linear meter per lane of the completed pavement or part thereof. The voids left by the core
sampling shall be backfilled by new materials.
The pavement’s compaction density shall be equal to 96% of the density of a laboratory
specimen prepared in accordance with the Marshall Stability Test.
Final Aggregate Sub-base course preparations shall be done at the shoulders,
immediately following the completion of Asphalt Concrete Overlay.
Submitted by:
GUO FENG
Project Manager
