PROCEDURE FOR ASPHALT CONCRETE PAVING AND ROAD ACTIVITIES-CIVIL

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PROCEDURE FOR ASPHALT CONCRETE PAVING AND ROAD ACTIVITIES

This Procedure describes the steps to be taken and sequence of events necessary to enable satisfactory completion of each activity.

Code & Standards Used for ASPHALT CONCRETE PAVING AND ROAD ACTIVITIES

SAES-Q-006 :    Asphalt and Sulfur Extended Asphalt Concrete Paving

SAES-A-114 :   Excavation and backfill

SABP-Q-010:  Mix design and Construction of Sulfur Extended Asphalt Concrete

AASHTO : AASHTO guide for Design of Pavement Structures. American Association of State highway and Transportation Officials, 1993.

AASHTO M 17: Standard Specification for mineral Filler for Bituminous Paving Mix

AASHTO M 156: Standard Specification for Requirements for Mixing Plants for Hot­Mixed, Hot-laid Bituminous Paving Mixture.
AASHTO T 49: Standard Method of Test for Penetration of Bituminous Materials.

AASHTO T 51: Standard method of Test for Ductility of Bituminous Materials.

AASHTO T 53 : Standard Method of Test for Softening Point of Asphalt (Bitumen) and Tar in Ethylene Glycol (Ring and Ball).
AASHTO T 180 : Moisture Density Relation of Soils using a 10-lb (4.54kg) Rammer And an 18 inch (457 mm) drop.
AASHTO T 193:  California Bearing Ratio

ASTM C88 :   Test Method for Soundness of Aggregates by use of Sodium Sulfate or Magnesium Sulfate.
ASTM C117 : Test Method for Materials Finer than 0.075mm (no.200) sieve in  Mineral Aggregates by Washing.
ASTM C131  :Test Method for Resistance to Degradation of Small-size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine.

ASTM C136 : Test Method for Sieve Analysis of Fine and Coarse Aggregates.
ASTM C142 : Test Method for Clay Lumps and Friable Particles in Aggregates.
ASTM C535  :Test method for resistance to Degradation of Small-large Coarse  Aggregate by Abrasion and Impact in Los Angeles machine.
ASTM D75: Particles for Sampling Aggregates.
ASTM D4791: Test method for Flat particles or Elongated Particles or Flat and Elongated particles in Coarse Aggregates.
ASTM D5 : Standard Test method for Penetration of Bituminous Materials.
ASTM D36: Standard Test for Method of Softening Point of Bituminous Materials.
ASTM D113: Standard Test Method for Ductility of Bituminous Materials.
ASTM D1559: Test Method for Resistance to Plastic Flow of Bituminous Mixtures using Marshall Apparatus.
ASTM D2041 : Test Method for Theoretical Maximum Specific Gravity and Density of  Bituminous Paving Mixtures.
ASTM D2172 : Test Method for Quantitative Extraction of Bitumen from Bituminous Paving Mixture.
ASTM D2726  : Test Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous Mixtures.
ASTM D2726 : Standard Test Method for Viscosity Determination of Asphalt at Elevated temperature using Rotating Viscometer.
ASTM PS 90-97 : Provisional Test Method for Asphalt Content of Hot-mix Asphalt by  the Ignition Method.
ASTM C5  :Standard Specification for Quicklime for Structural Purposes.
ASTM C150:  Standard Specification for Portland Cement.
ASTM D1156 : Test Method for Density and Unit Weight of Soil in place by the Sand-cone Method.
ASTM D1157 : Test Method for Laboratory Compaction Characteristics of Soil Using Modified effort (56,000 ft-lbs/ft3 -2,700 km/m3).
ASTM D2419: Test Method for CBR of Laboratory Compacted Soil.
ASTM D2922: Test Method for Density of Soil and Soil aggregate in Place by  Nuclear Methods (Shallow Depth).
ASTM D4253 : Test Method for Maximum Index Density and Unit Weight of Soils using a Vibratory Table.
ASTM D4254 : Test Method for Minimum Index Density and Unit Weight of Soils
TASTM D4318 : Test Method for Liquid Limit, Plastic Limit and Plasticity index of soils. and Calculation of Relative density.
ANSI/ASSE A10.12: Safety Requirements for Excavation
GI 1021.000 : Street and Road Closure, Excavation Reinstatement and Traffic

Preparation of sub grade

• Perform subgrade preparation. Fill all depressions, level the surface, remove all unsuitable materials and replace with materials approved by Saudi Aramco.
• Compact the subgrade according to the requirements in SAES-A-114 Section 6.3.1.1 and 6.3.2.5 (ARAMCO STANDARD)
• Following compaction, check for air holes, ruts, soft spots and other unsuitable subgrade conditions. Confirm compliance to Saudi Aramco Standard requirements.
• Where rolling is required, any areas inaccessible to a roller will be compacted by either mechanical or hand tamper until the Saudi Aramco requirements had been attained.
• Before placing base course layer, check conformance to alignment, grade, slopes and cross- sections shown on IFC drawings and as required by the Project Specifications.

• The entire subgrade shall be compacted to not less than 95% of the maximum dry density per ASTM D 1557 or AASHTO T180 at 1.5% of the optimum moisture content or to 85% of relative density determined by ASTM D4253 and ASTM D4254.
• Maintain the finished sub-grade smooth and in a compacted condition until placement of base course.
• The subgrade shall be checked and approved by the Client representative prior to starting construction of base course on any portion of the work.
• The subgrade level after final compaction and before placement of prime coat shall not vary by more than -+6mm as measured with 3m straight edge.

• The subgrade materials shall comply with SAES-Q-006 requirements (ARAMCO STANDARD).

Preparation and Laying of base course layer

Install only base course materials approved by Client.
Thickness of the base material shall be in accordance to the issued IFC drawings

• Base material shall be placed in layers of uniform thickness with approved spreaders and layer thickness shall not exceed 150mm after compaction unless and until it is approved to exceed 150mm by contractor/client.
When the base requires more than one layer, the previously placed and compacted base should be maintained free from foreign matter prior to placement of successive layers. The base materials shall be completed at optimum moisture (-+2-1/2%) the rolling shall continue until the base are compacted to not less than 95% & 100% of the maximum laboratory dry density as determined by ASTM D1557 or ASSHTO T180. In-pace density shall be measured by ASTM D2922 or ASTM D1556 or other approved methods. Testing shall be conducted at a rate of one test every 2000 ft. (180m2) of base.
The surface of the completed base shall not show any deviation in excess -+6mm when tested with a 3m straight edge. The completed thickness of the base shall be within -+6mm of the thickness indicated and the average thickness shall not be less design (Ref: SAES-Q-006, Clause: 5.2.2.3) ARAMCO STANDARD.
In no case, shall tin layers of fine materials be added to top layer of the base course in order to meet the required elevation. The surface if the compacted material shall be finished by blading or with automated equipment and rolled with a steel-wheeled roller.
• Where rolling is required, any areas inaccessible to a roller will be compacted by either mechanical or hand tamper until the Client requirements had been attained.

Placement of Prime coat

Prior to the application of prime coat the surface shall be cleaned of all loose dirt and other objectionable materials by means of approved mechanical sweepers, blower and hand broom.
Prime coat shall not be applied when the weather is foggy, rainy or in sandstorm. It shall be applied when the surface to be treated is dry and the atmospheric temperature is +16°C or above.
The prime coat shall be applied uniformly to the surface using a pressure distributor at a rate between 0.65 and 1.75 liters per square meter and at a temperature between 50°C and so0c for MC-70 and a temperature between 65°C and 105°C for MC-250.
The distributor truck shall be equipped with the measuring device to measure the rate of application of the prime coat.
In the case of any inaccessible area to the distributor truck, hand spray lance shall be used.
Prime coat materials shall be applied to a width of 300 mm greater on each side of the road than the specified width of the finished surface. Any area where prime coat is disturbed shall be repaired to the satisfaction of contractor/client.
The minimum curing time shall not less than 24 hours and shall be fully set and cured before placing asphalt mixture on the base. Prime coat application rate (lit/meter square) shall be tested at the start of the operation and every 10,000m2 here after.

Please read also:  Procedure for Concrete Repair-CIVIL

Please read also: PROCEDURE FOR PROPOSED BACKFILL WORKS -CIVIL

Placement of Asphalt base course

The materials for Asphalt concrete paving shall be as per the requirements in of SAES-Q-006 (Clause: 5.5.1)

Bituminous Paving Mixture 

Asphalt shall be petroleum asphalt cement, penetration grade 60-70, conforming to Client requirements.

• Mineral Aggregate
► Gradation: When tested according to ASTM C117 and ASTM C136 the combined mineral aggregates shall conform to the following grading.

Mineral Filler:

When the combined grading of the course and fine aggregates is deficient in material passing the no. 200 sieve, Mineral filler conforming to ASSHTO M17 shall be added as approved by the Company representative. Mineral filler shall conform to the following grading.

Physical Requirement: The combined mineral aggregates for base course and wearing course shall not consist of soft and friable materials and shall conform to the following physical requirements.

► Sulfur shall be pelletized elemental sulfur
► Job mix for the asphalt base course shall be as per the requirement of SAES-Q-006 and approved by Client.
► The hot mix asphalt concrete shall be placed only when the atmospheric temperature is +4°C or above and the existing surface is free from moisture, weather is not foggy or rainy.
► The hot mix asphalt concrete material truck will be covered with tarpaulins until unloaded.
► Temperature of sulfur extended asphalt mixtures shall be between 130°C and 163°C at plant and at least 139°C at the time of spreading and compaction.
► The compaction requirements shall be equal or greater than 96% of the marshal density per ASTM D1559, using material sampled at the road site.
► Where rolling is required, any areas inaccessible to a roller will be compacted by either mechanical or hand tamper until the Saudi Aramco requirements had been attained
► The existing pavement shall be saw-cut and tacked; the base course shall be primed prior to placing new hot mix asphalt.
► The minimum thickness of the compacted bituminous material shall not be more than 70mm per layer nor as indicated in the IDC drawings, in no case shall thin layers of fine materials be added to the top to achieve the required thickness of specific tolerance.

Placement of Tack coat

► Tack coat shall be applied prior to the placement of another layer of base course or wearing course.
► The tack coat shall be tested 10,000m2 prior to applications; the maximum rate of distribution for the tack coat shall be 0.25 liters per square meter or as directed by Client.
► The tack coat shall be applied uniformly and the atmospheric temperature and material on which the tack coat shall apply is more than 16°C, if the application of wearing course is delayed by more than three days, or if dirt, sand or other impurities have contaminated the tack coat then a new tack coat shall be applied after the original one has been swept clean.
► In the case of any inaccessible area to the distributor truck, hand spray lance shall be used.

Placement of Asphalt Wearing Course

· Placement and testing of asphalt surface course shall be performed as per clause 7.4 of this procedure.

Field Density Testing

Field density testing will be performed by utilizing a nuclear density meter method (ASTM D2950}. Cores for density and thickness will be taken daily from previous days’ production. Each core shall be marked as to the location from which the core was taken and shall be at the following rates production.

Uncompact Asphalt Concrete; Samples for extraction, gradation and marshal properties shall be taken daily at the following rates of production.

Tolerances

► Surface Tolerance: The surface tolerance will be tested with a four-meter straightedge at selected locations. The variation of the surface from the testing edge of the straightedge between any two contacts with the surface shall at no point exceed four (4) millimeters when placed on or parallel to the centerline of three (3) millimeters when placed perpendicular to the centerline of the roadway. All humps and depressions exceeding the specified tolerance shall be corrected by removing the defective work and replacing it with new material as directed by the Client representative.

► Tolerance of Thickness: Measurement of any core shall not be deficient by more than 10 mm or fifteen  (15) percent of the design thickness whichever less is.

Machines/Equipment’s Used for ASPHALT CONCRETE PAVING AND ROAD ACTIVITIES

Depending on the size of the area, site conditions, and accessibility, some /all of the following equipment can be used.

► Mixing Plant
► Asphalt Paver
► Cold Planners
► Compactors
► Vibratory Steel Drum Compactor
► Rollers
• Pneumatic Tire roller
• Steel Tire roller
• Steel Vibratory Roller
• Hand Operated Steel Wheel roller
► Motor Grader
► Water Tanker
► Sweeper or Air Compressor
► Trailers
► MC70/RC70 -Distributor Tanker
► Asphalt Cutter Machine, if required
► Survey Equipment
• Auto level
• Total station (Surveying instrument for checking the levels & distances)
► Oil Distributor
► Wheel Barrows