Method Statement for Asphalt Paving Works
Method Statement for Asphalt Paving Works
(Civil
Engineering)
Effective Date:
Document No.:
Approved By: Eng. Muhammad Arif
PROJECT NAME: --------------------------------------------------------------------------
2). INTRODUCTION
HEALTH, SAFETY & ENVIRONMENT
(HSE)
Emergency Procedure
Document No.:
Approved By: Eng. Muhammad Arif
PROJECT NAME: --------------------------------------------------------------------------
SAMPLE 1
TABLE OF CONTENT
1.
ACTIVITY
2.
INTRODUCTION
3.
TERMINOLOGY
4.
SIGNIFICANT HAZARDS IDENTIFIED
5.
ROLES & RESPONSIBILITY AND
ORGANIZATION CHART
6.
SEQUENCE OF ACTIVITIES WITH
RESPONSIBILITIES
6.1 Pre-commencement Requirements
6.2 General Requirements
6.3 Co-ordination with Other Trades
6.4 Delivery, Storage & Handling of
Materials
6.5 Execution
7.
REQUIREMENTS
7.1 Plans/Records & Job instructions (Documentations)
7.2 Training
7.3 PPE (Personal Protective Equipment)
7.4 Equipment & Tools required
8. HSE & Emergency Procedures
9. ReferenceS
10. AttachmentS
- ACTIVITY: LAYING OF ASPHALT ROAD
This activity deals with the installation
and sequence of Laying of Asphalt road as per approved drawings and project
specifications and to ensure that the works are carried out in accordance with
the HSEQ documents.
2). INTRODUCTION
The
purpose of this method statement is to describe the procedure which shall be
followed for Laying of Asphalt road to comply with
schedule of finishes, the General, Architectural & Civil Specifications for
the Project and Owner / Engineer requirements.
3). TERMINOLOGY
O/E: Owner /
Engineer
PPE: Personal Protective Equipment
QC: Quality Control
4).
SIGNIFICANT HAZARDS IDENTIFIED
·
Respiratory hazard
·
Injury to person
·
Wrist Pain/Stress/fatigue
·
Slip/trip/fall hazards
·
Back injury
·
Vehicles movement
·
Sharp edges
·
Cut Injury
·
Injury to Eye/Eye Irritation
·
Chemical usage hazard
·
Machinery
·
Work related upper limb disorders
·
Electric Shock
5).
ROLES & RESPONSIBILITIES AND ORGANIZATION CHART
· Project Manager
(Main Contractor)
o
The project
manager is responsible for overall implementation of this Method Statement and
HSEQ related to this activity.
o
Ensure that the Site
construction and his team will aware of this Method Statement
o
Site construction
and his team will report to the project manager.
· Construction Manager
(Main Contractor)
o
Make arrangement
for availability of all relevant documents.
o
Ensure the availability of
necessary documents & resources available with Subcontractor.
o
Liaison with Owner/Engineer &
Subcontractor in-charges for necessary test & inspection.
o
Tracks the schedule & plan work
accordingly.
o
Liaison with all Electrical/MEP
work in-charges for all interfaces works and plans the work accordingly at
site.
· Engineer (Main
Contractor)
o
Ensures the control at work spots
in person.
o
Verifying the percentage compliance
as per risk assessment.
o
Ensures the emergency preparedness
of team and taking the part in Subcontractor’s TBT (Tool Box Talk)
o
Ensures the work carried out as per
latest approved drawings.
o
Ensure availability of necessary
resources and approved documents.
o
Inspects the incoming materials in
line with approved documents.
o
Ensure the quality
of work/material and readiness for inspection.
· Safety Officer
(Main Contractor)
o
Responsible for ensuring HSE at all
stages of work.
o
Ensures the compliance of all control
measures at site as per approved risk assessment plan.
o
Ensures for all
checklist as per HSE plan.
· Project Manager
(Subcontractor)
o
Ensure that
appropriate resources are provided for the safe delivery of the work
· QA/QC Engineer
(Subcontractor)
o
Ensuring quality of work carried
out at site
o
Ensuring for inspection on hold
points
o
Maintaining all QC records
o
Coordinating with
O/E for inspections
· Site In charge
(Subcontractor)
o
Ensuring the relevant document
o
Plans the
necessary men and material resources for
timely completion and quality
· Site Engineer
(Subcontractor)
o
Ensuring the controls at work spot
in person
o
Verifying the % compliance as per
risk assessment.
o
Ensuring the emergency
preparedness.
o
Arranging the required inspections
and permit
o
Ensures all scaffolding
erected safely and scaffolding tag
system followed
o
Ensures availability of the
necessary resources.
o
Ensuring
availability of all activity relevant latest approved drawing and documents
· Supervisor /
Foreman (Subcontractor/Supplier)
o
Obtaining the permit (if required
-e.g. Steel cutting)
o
Conducting Tool Box Talk (TBT) based on risk assessment
o
Arranging for appropriate tools and
necessary skilled work force as required.
o
Ensuring the works are carried out
as per approved and latest drawing/documents
o
Ensuring for Housekeeping always at work place
o
Implementing the control measures
as per risk assessment and also as mentioned in the permit.
o
Close monitoring till completion of
work.
o
Close the work
permit after restoration of work spot.
· Workmen (Subcontractor/Supplier)
o
Wearing appropriate PPEs.
o
Understanding and following the
instructions given by line staff.
o
Following the scaffolding tag
system
o
No horseplay and shortcuts.
o
Informing the
supervisor/foreman about any near misses, injuries and unusual
· Safety
Officer (Subcontractor)
o
Ensures all safety measures
implemented/followed as per risk assessment and HSE Plan
o Should inform the site engineer for
any deviations from required procedure/standard practice
o
Should conduct a safety briefing in
co-ordination with site engineer/supervisor over a specific HSE issue
o
Ensure all First aid cases are
entered in first aid register and
necessary awareness given to the victim
o
Ensures for
inspection of power tools and scaffolding
· Surveyor
(Subcontractor)
o
To check the levels, coordinates
and alignments of every work activity at site.
· Organization Chart
(see for attachment)
6). SEQUENCE OF ACTIVITIES WITH RESPONSIBILITIES
6.1
Pre-commencement
Requirements
· Approval of work procedures shall be
obtained from O/E prior to the start of activity.
· Asphalt mix design test results
shall be submitted to the O/E’s review.
· Safety regulations as per
specifications and standard shall be followed
6.2
General Requirements
Before start of the work the following
shall be ensured:
· Tools, Equipment & Machinery is
suitable and approved for use.
· Availability of suitable quantity of
approved material for the works as per specification and O/E requirements.
· Area clearance obtained from other
discipline/subcontractor.
6.3
Co-ordination
with other trades
· No Laying of asphalt road work to be
started unless it is cleared for Laying works.
· Prior to start the works, check all
architectural, mechanical and electrical works are completed and MEP clearances
shall be taken as required.
6.4
Delivery,
Storage & Handling of Materials
· All materials shall comply with the
specifications regarding quality, dimensions, strength etc.
· The material shall be approved and
shall be used as per the Approved drawings.
· Materials received at site shall be
checked by O/E.
· Sampling / testing to be done as per
requirements of specification
6.5
Execution
: Procedure for laying Asphalt road works
A) Surface Preparation
· The
surveyor shall mark the road center line and width of the embankment prior to
starting of any road works; The CONTRACTOR shall make detail survey of the
existing services (If any) by the side of the road or crossing the road
· Surveyor shall make a survey report for the
existing levels prior to filling or cutting and engineer should make sure for
the same
· All the
road works and road crossings must be executed as per the approved drawings and
as per project specifications.
B) Road embankment
·
Embankment
shall be installed on top of the existing natural ground, thickness of this
layer shall be at least 30 cm
·
Material
to be used for road embankment shall be A-1-a OR A1-b or A-2-4 in accordance
with AASHTO Soil Classification System (from AASHTO M 145 or ASTM D3282).
· Every
layer should be compacted with heavy compactor and the compacted density of the
soil shall be equal to or greater than 95% M.D.D., with no single value below
92%.
C) Sub-Grade
· Ensure that approved sub-grade material is
used and the material sample shall be collected and tested as per project
specifications upon receiving of material at site.
· Sub-grade material shall be placed above
embankment filling
· The approved Sub-grade material shall be back-filled to the thickness of 300 mm and it should back-filled in two layers
(each layer 150 mm ).
· Compaction of sub-grade shall be
facilitated by means of a 10-12 ton roller, rolling shall be continue to
achieve the Max. Dry Density(MDD) of 98% as per approve drawings and project specifications.
· Thickness of sub-grade shall not be less
300 mm as specified in the approved drawings
· The formation shall be shaped and graded
to an even and uniform, well filled surface, shaped similarly to the finished
surface of the road
· Compaction test shall be done by approved
laboratory for the Sub grade.
D)
Laying of Kerbstones
·
The above
work shall be carried out according to the Method statement submitted vide WS-CRN-DAR-CV-MS-1360 dated 22.10.2018.
·
Laying of Kerb stone shall be inspected and approved by O/E.
E)
Sub-Base
· Ensure that approved sub-base course
material is used and the material sample shall be collected and tested as per
project specifications upon receiving of material at site.
· Thickness of sub-base course shall be 200 mm
as specified in the approved drawings, and it shall be placed in two layers.
· Sub Base material spreading shall be
started after receiving the compaction test results of Sub Grade.
· Sub-base material loads shall be spread outside
area on which it is spread to ensure that no segregation occurs and it shall be
spread evenly using a grader to maintain the levels and thickness of layers.
· Each layer shall be must be compacted to an average of 100% of
MDD with no single value below 98%
· Minimum field density tests shall be one
test for every 300 m2 of
granular sub-base laid
· Minimum material test requirement shall be
one sample for every 1,000 cum of material and test shall be as follows grading,
plasticity index, sand equivalent, MDD, and CBR, loss by abrasion by the
approved laboratory as per the project specifications.
F)
Aggregate Base Course (ABC):
· Ensure that approved sub-base course
material is used and the material sample shall be collected and tested as per
project specifications upon receiving of material at site.
· Thickness of sub-base course shall be 150 mm
as specified in the approved drawings.
· Aggregate base course material spreading
shall be started after receiving the compaction test results of Sub Grade.
· Aggregate base course material loads shall
be spread outside area on which it is spread to ensure that no segregation
occurs and it shall be spread evenly using a grader to maintain the levels and
thickness of layers.
G)
Prime Coat (MC1):
· Ensure that approved material is used and
each consignment test certificate for prime coat (MC-70) shall be provided.
· Prime coat shall be tested as per project
specifications.
· Prime coat shall be applied between road
base course and bituminous base course as per approved drawings
· The same shall be cured for a curing
period of 48 hours prior to laying of bituminous base course
· Bituminous material for the prime coat
shall be applied in quantities of at least 0.7 ltr/m2, not exceeding
however 1.50 ltr/m2.
H)
Bituminous Base Course (BBC):
· Ensure that approved Bituminous base
course material is used and each consignment test certificates shall be
provided for Asphalt cement used (AC 40-50).
· Bituminous base course shall be of
thickness 90mm as per approved drawings.
· Bituminous base course shall not be placed
during dusty, foggy and Rainy weather.
· Bituminous base course material shall be
transported in trucks from hot mix plant & its final placement temperature
shall not be less than 150º C.
· Consistency of mixture shall be checked
for each 200 tons.
· Site engineer in coordination with
surveyor must ensure laying of bituminous course to the correct levels and to
the specified longitudinal and cross section profiles.
· The Bituminous base course shall be evenly
placed by mechanical spreader on a clean base in a manner that it does not
become segregated.
· The seams of the bituminous base course
shall be sufficiently staggered against each other and it should be executed
straights, longitudinal if necessary being adapted to the road alignment.
· Bituminous base course shall be compacted
evenly over the entire surface by using pneumatic & steel roller.
· Gradient slope shall be maintained as per
approved drawings.
· The core sample to be taken after
compaction to determine the layer thickness and the MDD as per project
specifications.
I)
Tack Coat (RC2):
· Ensure that approved material is used and
each consignment test results shall be provided for Tack Coat (RC2).
· Tack coat shall be tested as per project
specifications.
· Tack coat shall be applied between
bituminous base course and the wearing course as per the Project Drawings.
· Tack coat shall be cured for at least 1
hour
·
Tack coat
shall be applied in quantities of at least 0.3 ltr/m², not exceeding,
however 0.60 ltr/m²
J)
Wearing Course (BWC):
· Ensure that approved material is used and
each consignment test certificates shall be provided for Asphalt Cement used
(AC 40~50).
· Temperature of mixture to be measured at
site and it should not less than 1500C.
· Consistency of mixture shall be checked
for each 200 tons.
· Thickness of wearing course shall be 60 mm
as per approved drawings
· Wearing course shall be placed in one
layer above the bituminous base course and one coat of tack coat shall be
applied between bituminous base course and wearing course.
· The Wearing course shall be evenly placed
by mechanical spreader on a clean base in a manner that it does not become
segregated.
· The seams of the wearing course shall be
sufficiently staggered against each other and it should be executed straights,
longitudinal if necessary being adapted to the road alignment.
· Wearing course shall be compacted evenly
over the entire surface by using pneumatic & steel roller.
· Site engineer in coordination with the
surveyor must ensure the top levels and slope is maintained as per approved
drawings.
· The core sample to be taken after
compaction to determine the layer thickness and the MDD as per project
specifications.
K) Temperatures
· Temperature shall be checked whenever
material is delivered to site
· Aggregate ingredient shall be heated to a
temperature between 160áµ’ to 179áµ’C
· Asphalt cement shall be heated to a
temperature between 146áµ’ and 156áµ’ C at mixing time
· All bituminous mixtures shall leave the
paver at a temperature not less than 150áµ’C
· Prime coat (MC1) between 50áµ’ and 80áµ’C
· Tack Coat (RC2) between 10áµ’ and
50áµ’C
L) Joints
· Longitudinal joints in asphalt courses
shall be offset by 300 mm in relation to the longitudinal joints of the
underlying course
· Transverse joints in succeeding layers
shall be offset by at least 2 m. The same shall apply when new pavement is laid
in contact to an existing, which will be cut back in steps, 2m wide in each of
its layers
· At transverse joints the previously laid
work shall be cut to a vertical edge. Before laying the material against it,
the vertical edge to be painted with hot bitumen
· Minimum number of joints to b
exercised/considered during execution
M) Compaction of Mixtures
· After spreading and strike-off, the
rolling operation by pneumatic and stell roller shall start immediately and
shall operate as close as possible to the paver without excessive tearing
· Rolling will not be prolonged till cracks
appear
· The asphalt layer shall be compacted to a
minimum degree of 98% of compaction
N) Thickness of Cores
· Depth of each bituminous paving course
shall be measured by cored samples
· Samples shall be one sample for 600 M²
· Cored sample shall be 10 cm in diameter
(nominal)
O) Surface Tolerances
v Non Bituminous Courses
· The
thickness and cross section as shown on the approved drawings shall not vary
more than -5 mm to +10 mm from the required elevations.
v Bituminous
Courses
·
Maximum
variations allowed for 3 M shall be :
Ø Base Course = 4 mm
Ø Wearing Course = 3 mm
P) Road Markings
·
Road markings shall be
applied wherever necessary or as directed by ENGINEER to control and direct the
traffics.
·
Road markings shall be
marked by thermoplastic as per project specifications.
·
Road markings shall be
sprayed on the road in an even thickness of 2.0 mm.
Q) Inspection and Testing
·
Each activity like back-filling of Sub grade
and Sub base, In-situ Density test for Sub base & Sub grade and laying of Bituminous
base course and Wearing course work shall be intimated to O/E through
inspections.
·
After due completion of laying of Asphalt
work shall be offered to O/E’s inspection and comments on the work shall be
rectified and notified for re-inspection if any.
·
Testing of
each consignment delivered to the site shall be carried out as per the
specifications for road works of RIYADH AMANAH.
7). REQUIREMENTS
7.1
Plans /Records and Job instructions
(Documentations)
Before
commencing the work the following things should be available:
·
Inspection request for materials, erection
& installation
·
Approved drawings / Material
approval for the work
·
Method statement for the work
·
Key site plan for that work area
·
All inspected tools &
machineries
· Emergency
escape route without obstructions
· Clearance
from Electro-Mechanical incharge
7.2 Training
· Trained/Experienced
& Skilled persons shall be used for the work
· All
operator / Laborers are safety trained and toolbox shall be conducted for the
each potential hazards mentioned in the Risk assessments.
7.3
PPE (Personal Protective Equipment)
· Protective
clothing
· Protective
gloves
· Safety
helmet
· Safety
goggles
· Hard
Gloves
· Hi-visibility
jacket
· Flagging
tape
· Warning
tape
· Flasher
light
· Safety
Harness (above 1.8m)
7.4
Equipment and Tools required
·
Manpower requirement
1.
General Supervisor/Foreman - 01 no
2.
Charge hand - 02 nos.
3.
Mason - 02 nos
4.
Helpers - 06 nos.
5.
Electrician - 01 no.
·
Equipment
1.
Shovel
2.
Compaction roller machine
3.
Spreader
4.
Trucks
5.
Sprit level
6.
Plumb bob
7.
Electric air blower/Air compressor
for cleaning
8.
Drilling Machine
9.
Hammer
10.
Measuring Tapes
11.
Marker
7.5 Risk Assessment
·
Risk assessment to be ensured that
it is available in the work spot
·
All control measures as per risk
assessed to be implemented and ensured before start of work
·
All workers shall be made aware of
the risk involved in carrying out the activity and requirement of control
measures during toolbox talk
8). HSE
& EMERGENCY PROCEDURES
HEALTH, SAFETY & ENVIRONMENT
(HSE)
v The entire works will be
carried out as per the guidelines established in the Project Specific HSE Plan
v Utmost importance shall
be given to safety or personnel and protection of existing above/under ground
services. It will be ensured that the personnel involved are thoroughly aware
of the safety regulations. To achieve the above the following shall also be
ensured:
·
Tool
box meetings will be conducted before starting the works
·
All
personnel will be provided with suitable personal protective equipment
·
Required
permits will be obtained from the authorities concerned before starting the
works, if any
·
Plant
& equipment will be fully tested for safety compliance
·
Proper
and safe access will be provided for workers to reach the work spot and carry
out their works safely
·
Necessary
and essential lighting and ventilation will be provided during the course work
to protect labor from suffocation
·
Scaffolding
and working platforms provided to facilitate the works will be checked
frequently for its safety
·
The
necessary safety measures will be taken to prevent accident or injury all the
times. This may include barriers, warning tape / net, signage, watchman,
flashing & rotating lights at night
·
Heat
Stress training will be provided during summer season
·
Provision
of adequate cool drinking water, shades if necessary will be arranged in place
·
Plants
& Equipment will be provided with back-up lights and all other applicable
safety devices
Emergency Procedure
· In case of any emergency
situation the workmen should follow the emergency response procedure and must
gather in the assembly point. The emergency response procedure should be
conveyed to the work men through the toolbox talk in prior to the carrying out
of the activity.
· The necessary safety
measures will be taken to prevent the accident or injury all the times. This
may include barriers, warning tape, net, signage, watchman, flashing &
rotating lights at night.
· MSDS shall be made
available prior to the start of the job
· Heat stress training
will be provided during summer season.
· Provision of adequate
cool drinking water, shades if necessary and salt tablets will be in place.
· Plants & equipment
will be provided with back up lights and all other applicable safety devices.
v In case of major
Injuries
Ø Do
not panic. Call ambulance and notify emergency team at site
Ø Do
not move the injured unless he is in danger
Ø If
danger exists, he shall be assessed by a trained and qualified first aider
before moving. Use a stretcher.
Ø Do
not crowd around the victim. Do not give anything to eat or drink. Ensure adequate air and lighting.
Ø Only
trained and qualified first aider shall treat the victim and ensure that his
airway is kept clear.
Ø Victim
shall be transported to hospital in an ambulance.
Ø Preserve
the accident scene for further investigation.
v In case of Fire
Ø Follow
Amanah/s approved emergency procedure as per HSE Plan.
v In Case of Flood
Ø Evacuate
immediately to the nearest highest location you are in.
Ø Notify
the Emergency Controller of the site
v EMERGENCY CONTACT
NUMBERS:
Name
|
Position
|
Contact Nos.
|
Project Manager
|
||
Site Manager
|
||
Safety Officer
|
||
Fire Fighter / First Aider
|
||
Pick Up driver
|
POLICE
|
999
|
AMBULANCE
|
998
|
FIRE SERVICE
|
997
|
HOSPITAL
|
HMG
011 4909999
|
9). REFERENCES:
§ S-TR-CIVIL-Road (Rev.0-2010)
§ Project Quality Plan (PQP)
§ Project HSE Plan
§ Drwg. No. N7204.1E-R-E-5370-S-7151 Rev. A Sheet 1~1
§ Drwg. No. N7204.1E-R-E-5370-S-7201 Rev. A Sheet 1~1
§ Drwg. No. N7204.1E-R-E-5370-S-7212 Rev. A Sheet 1~2
§ Drwg. No. N7204.1E-R-E-5370-S-7401 Rev. A Sheet 1~1
§ Drwg. No. N7204.1E-R-E-5370-S-7402 Rev. A Sheet 1~1
§ Drwg. No. N7204.1E-R-E-5370-S-7351 Rev. A Sheet 1~1
§ Drwg. No. N7204.1E-R-E-5370-S-7352 Rev. A Sheet 1~1
§ Drwg. No. N7204.1E-R-E-5370-Q-7001 Rev. A Sheets 1~7
§ Drwg. No. N7204.1E-R-E-5690-H-7113 Rev. A Sheets
§ Ref. No. N7204.1E/MASS/0235- ASPHALT MIX DESIGN
10).
ATTACHMENTS:
ü S-TR-CIVIL-Road (Rev.0-2010)
ü Organization Chart
ü Risk assessment sheets
ü Approval
copy of Asphalt Mix Design
ü Standard
Drawings
ü Reference
Drawings
--------------------------------------------------------------------------------------------------------
Method Statement for Asphalt Paving Works
(Civil Engineering)
Effective Date:
Document No.:
Approved By: Eng. Muhammad Arif
PROJECT NAME: --------------------------------------------------------------------------
Document No.:
Approved By: Eng. Muhammad Arif
PROJECT NAME: --------------------------------------------------------------------------
SAMPLE 2
1. Scope:
The scope of work of
this method statement is to describe the responsibilities of personnel
involved, execution procedure, safety factors and documents to be recorded for
Asphalt Paving Works.
2. Relevant Process/Specifications:
Tender Specifications
3. Responsibility:
The Construction
Manager/Project Engineer is responsible for the asphalt paving works.
The Civil Construction
Contractor’s Safety Officer shall ensure that necessary work permits are
availed before the work commences and that the work is carrying out in safe
manner.
The responsibility of
the survey activities lies with asphalt paving work subcontractor. The survey
team of civil construction contractor shall verify the data frequently.
Inspection and testing
activities shall be controlled by the QC Engineer of Civil Construction
Contract or through the site laboratory of Company.
4. Plants and Equipment:
Bitumen spray tankers,
asphalt paver, Tandem steel roller, hand rollers, asphalt batching plant, etc.
5. Execution Procedure:
Prior
to Commencement:
Safety:
Prime importance shall
be given for personnel safety and protection of utility lines/services. It
shall be ensured that the personnel involved are aware about the Company Safety
regulation and confirm that the machinery are regularly maintained. Further
to above, the following key points shall be considered important.
a. Copies of
drivers/operator’s license vehicle’s registration and security passes to be
submitted to Company safety department before commencing the work.
b. All moving
vehicle/equipment shall have reverse horn.
c. Transporting of
persons per vehicle is restricted to the number of seat belts available in the
pickup.
d. Deep excavations
shall be adequately shored, barricaded and warning signs & lights shall be
posted.
e. Road safety
signs/road diversion signs shall be installed wherever applicable for the safe
movement of vehicles and equipment.
f. All major equipment
shall be tested and certified by Third Party prior to mobilization to site.
Existing
Services and Facilities:
a) Before commencement
of the work, ascertain the nature and location of all existing above and
underground services at site by visual survey and reviewing the service layout
drawing (if available)
If any protection, re
-routing, termination or removals of services are required for the smooth
progressing of work, it shall be discussed and written approval shall be
obtained from employer/ company as appropriate. For service protection,
approved method of protection shall be adopted.
b) A warning tape shall
be tied at a distance of 2 meters away from the services/as warning sign, to
restrict the movement of the equipment.
Survey:
a) Establish and protect
sufficient number of stations to re-establish the stations if they are
disturbed during work.
b) Post wooden stack for
line and gradient of the road.
c) The existing sand
tracks shall be blocked, re-routed and traffic diversion signs shall be posted
prior to the commencement of the work.
In-Process
Procedure:
The execution procedures
shall be divided into following sections, which are:
a) Prime Coat.
b) Binder course.
c) Tack coat.
d) Wearing course.
a)
Prime Coat (MC1):
Quality of Primer should
be as per BS:1707
Immediately before
applying the prime coat (which shall be preliminary approved), the full width
of the surface shall be cleaned with compressed air (Using Compressor).
i) The bituminous
material for the prime coat (MC1) shall be applied by means of bitumen spray tankers.
ii) This shall be
applied in a single layer at the rate of 0.7 – 1.5 liters /m² and at a
temperature not exceeding 70° C. This surface shall be cured for 24 hours.
iii) The over spread
area shall be cured more than 24 hours/ until excess prime coat is evaporated.
b) Bituminous Binder Course (BBC):
Quality of Binder should
be as per AASHO-T182
i) Immediately before
paving the binder course material (Bituminous Binder Coarse - BBC), the surface of the prime coat shall be
cleaned with compressed air and shall be ensured that the surface is dry.
ii) The hot asphalt mix
shall be brought from the approved mixing plant by 6 wheel trucks or trailers. Upon
arrival at site, the asphalt mix shall be dumped into the asphalt paver.
iii) The asphalt paver
shall lay the material to the required thickness and level.
iv) The mix shall be
compacted as soon as possible after spreading the material. Tandem rollers
shall follow the laying operation to carry out breakdown rolling up to
temperature of 110°C- 120° C. Pneumatic tired rollers and tandem rollers shall follow the breakdown
rolling and sufficient passes shall be made to achieve the required compaction.
Rolling shall start from
the sides and proceed toward the center. Each trip of the roller shall overlap
the previous trip by at least 30 cm. Roller wheel shall be kept moistened. The
roller shall be capable of reversing without backlash and shall be free from
worn parts.
Heavy rollers shall be
used to complete all rolling including elimination of waves caused by the
lighter rollers. Full compaction shall be obtained before the asphalt
temperature reaches 100°C. Compaction shall be in accordance with specification
of relevant standard.
v) The construction
joints shall be prepared by cutting the layer vertically down by means of
asphalt saw cutting machine or with jack hammer. The joint shall be cleaned
well by compressed air and tack coat (RC2) material shall be applied on the vertical
and horizontal surface for better bonding. Extremely good care shall be taken
when asphalt is laid at construction joints.
vi) The areas inaccessible
for heavy rollers shall be compacted with plate compactors or hand tampers.
After reaching the base course top level, suitable fill material (Dune Sand)
shall be dumped to the top level of base course on the sides of road shoulders.
It shall be leveled, shaped (1:6 Ratios) and compacted to 90% maximum dry
density.
c) Tack Coat (RC2):
i) The material (which
shall be primarily approved) shall be applied at the rate of 0.3 to 0.6 lit/ m²
at the temperature not exceeding 54°C above the binder and at where there is a
joint with existing asphalt surface.
ii) The surface shall be
cured for the period as per manufacturer’s recommendations until a tacky
surface is visible.
d) Wearing Course (WBC):
i) The hot asphalt mix
shall be spread over the cured surface of tack coat by automatic asphalt paver
to the required profile and thickness.
ii) The mix shall be
compacted as soon as possible after spreading the material. Tandem roller shall
follow the laying operation to carry out breakdown rolling up to a temperature
of 110°C- 120°C.
Self-propelled rollers
and Tandem rollers shall follow the breakdown rolling and sufficient passes
shall be made to achieve the required compaction.
Rolling shall start from
the sides and proceed toward the center. Each trip of the roller shall overlap
the previous trip by at least 30 cm.
Roller wheels shall be
kept moistened. The roller shall be capable of reversing without backlash and
shall be free from worn parts. Heavy tandem roller (CC-41) shall be used to
complete all rolling including elimination of waves caused by the lighter
rollers Full compaction shall be obtained before the asphalt temperature
reaches 80°C. Compaction shall be in accordance with specification of
relevant standard.
iii) Traffic shall not
be allowed on this layer until it is properly cooled, a minimum period of 12
hours shall be considered after the completion of the rolling.
iv) The test holes shall
me made good with hot asphalt mix and compacted using Marshal Hammer.
Inspection
and Testing:
Testing shall be
conducted by Company’s 3rd party site laboratory.
Relevant QC records shall be raised by Civil
Construction Contractor’s QC Engineer. Also tests shall be carried out as per
the Field Quality Control Plan (FQCP) of Asphalt Work.
Author: Eng. Muhammad Arif (Dar Al Handasah) Saudi Arabia
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