ASPHALT CONCRETE PAVEMENT

ASPHALT CONCRETE PAVEMENT


PART 1 - GENERAL

1.1      THE REQUIREMENT

A. The CONTRACTOR shall furnish all tools, equipment, materials, and supplies and shall perform all labor required to complete the new pavement and over lay work as indicated in the Contract Documents and specified herein.

B.         All materials and procedures shall comply with the rules and regulations of the South
Coast Air Quality Management District.

1.2 RELATED WORK SPECIFIED ELSEWHERE

A. Section 02200, Earthwork

1.3      REFERENCE SPECIFICATIONS, CODES AND STANDARDS

A.         Comply  with  the  applicable  reference  specifications  as  specified  in  the  General
Requirements.

B. Work of this Section shall be performed in accordance with the Standard Specifications for Public Works Construction (SSPWC), unless otherwise specified herein.

1.4      CONTRACTOR SUBMITTALS

A. Submittals  shall  be  made  in  accordance  with  the  General  Requirements,  and  the requirements of this Section.

B. Samples:   Prior to the delivery of specified aggregate to the site, the Contractor shall submit samples of the material for the Engineer’s acceptance in accordance with SSPWC Section 4-1.4.  Samples shall be typical of materials to be furnished from the proposed source and in conformance with the specified requirements.

C. The  Contractor  shall  formulate  a  job-mix  formula  using  the  Marshall  Method  in accordance with SSPWC Section 203-6.3.2 and submit it to the Engineer for approval. The resultant mixture shall have Marshall properties conforming to SSPWC Section 203-
6.3.2.

D.         Certificates

1. Twenty days prior to the delivery of aggregates, asphalt materials, and paving mixes to the project site, the Contractor shall submit to the Engineer certificates and test results of compliance of such materials with these Specifications.

2. Where laboratory testing is specified herein, the Contractor shall employ an independent testing laboratory to conduct such tests and submit certificates of the test results.

1.5      QUALITY ASSURANCE

A.         The Engineer may inspect the asphalt production plant.

B.         The Contractor shall be responsible for quality control.

PART 2 - PRODUCTS

2.1      GENERAL

A. The Contractor shall make all tests necessary to locate a source of materials that meet the Specifications.   Final approval of the aggregate material will be based on tests of material taken by the Contractor from the compacted base course.

2.2      AGGREGATE BASE

A. Aggregate base shall conform to the provisions of the latest edition of the Standard Specifications for Public Works Construction (SSPWC), Subsection 200-2.2, Crushed Aggregate Base (CAB), or Subsection 200-2.4, Crushed Miscellaneous Base (CMB). CMB shall have only the fine gradation. Aggregate shall be asbestos free.

B. In lieu of the second sentence of SSPWC, Subsection 200-2.4.1, at least 65 percent by weight of the material retained on the No. 4 sieve shall be a crushed particle as determined by Test Method No. California 205.

C. Evaluation of gradation and sand equivalent test results shall conform to the provisions of SSPWC, Subsection 400-1.4.   The gradation and sand equivalent requirements of SSPWC, Subsection 200-2.4 shall be the moving average requirements.

2.3      ASPHALT CEMENT

A. Asphalt cement for binder shall be paving asphalt and shall conform to the requirements of SSPWC Section 203-1 Paving Asphalt.

2.4      PRIME COAT

A. Asphalt to be used for a prime coat shall be liquid asphalt SC-250 and shall conform to the requirements of SSPWC Section 203-2 Liquid Asphalt.

2.5      TACK COAT

A.         Asphalt emulsion shall be CSS1 or CSS-1h and shall conform to the requirements of SSPWC Section 203-3 Emulsified Asphalt.

2.6      EMULSION-AGGREGATE SLURRY

A.         Materials for emulsion-aggregate slurry shall be as specified in SSPWC Subsection 203-5.

2.7      ASPHALT CONCRETE

A. Asphalt concrete for paving the designated area shall be Class C2-AR-4000 hot-plant mix and shall conform to the requirements of SSPWC Section 203-6 ASPHALT CONCRETE.

B. Asphalt content in the pavement shall be 5.5 percent to 6.0 percent by weight. Asphalt concrete (AC) paving shall conform to C2-AR-4000 as defined in SSPWC, Subsection
400-4.  Asphalt shall be viscosity grade AR 4000.

C.         Aggregate  shall  be  in  accordance  with  SSPWC  Subsections  400-1.1  and  400-1.2.
Aggregate shall be asbestos free.

D. Coarse aggregate shall consist of material of which at least 75 percent by weight shall be crushed particles in lieu of the requirements of SSPWC, Subsection 400-4.2.3.

2.8      WEED KILLER

A.         Weed killer shall be Karmex 80, as manufactured by Dupont Chemical Company, or
Diuron 4L, as manufactured by Drexel Chemical Company, or equal.

PART 3 - EXECUTION

3.1      EXCAVATION AND BACKFILL

A.         Excavation and backfill are specified in Section 02200, Earthwork.

3.2      PREPARATION OF SUBGRADE

A.         Subgrade shall be shaped and compacted in accordance with SSPWC Subsections 300-
4.7 to 95 percent relative density.

B. Use of the prepared subgrade for hauling will not be permitted.   The Contractor shall protect the prepared subgrade from all traffic.

C. The subgrade shall be maintained in the finished condition until the first succeeding course is placed.

D. Unless specified otherwise on the Contract Documents, the upper 30 inches of subbase, the Street Zone, shall be compacted to not less than 95 percent relative density. Compaction operations shall be in conformance with Section 02200, Earthwork.

3.3      BASE COURSE

A. Place crushed aggregate base in a uniform layer over the entire area to receive base course, without segregation of size, to such loose depth that when compacted with the power roller, the course shall have the required thickness shown on the drawings. Compact   over   the   full   width   until   a   density   of   95 percent   as   determined   by AASHTO T 180 is obtained.  Blade the base with a grader and roll, while damp, with the power roller specified above until the course is thoroughly and uniformly compacted and its surface is smooth and conforms to the grade requirements specified.   Maintain the surface in its finished condition until the succeeding layer is placed.

3.4      WEED KILLER

A. After the subbase has been prepared, weed killer shall be applied to the entire base. The weed killer shall be applied according to the manufacturer's published instructions.

3.5      PRIME COAT

A. After treatment with weed killer, the aggregate base course shall be primed prior to application of the asphalt concrete in accordance with SSPWC, Subsection 302-5.3.

B. The prime coat shall be applied only when the base course surface is dry or slightly damp. Depending on weather, a light application of water may be required prior to application  of the  prime coat,  which  will  permit  uniform  distribution  and  the  desired penetration. The  prime  coat  shall  not  be  applied  when  the  ambient  atmospheric temperature is below 60° F.

C. The prime coat shall be applied at a temperature of 175° F to 225° F, and at a rate of 0.3 to 0.4 gallons per square yard.

D. Following the application of the prime coat material, the surface shall be allowed to dry for at least 48 hours without being disturbed, or for an additional period of time as may be necessary to attain penetration of the prime material into the base course, and drying out or evaporation of the volatiles in the prime coat material.   Traffic shall be kept off the prime coat until it has penetrated the base course and cured.  No prime coat drying time limit is imposed on public streets where fast completion is important.   The Contractor shall furnish and spread enough imported sand on all areas that show an excess of bituminous material to effectively blot up and cure excess prime coat material.

E. The primed surface shall be maintained by the Contractor until the succeeding layer of pavement has been placed.  During this interval, the Contractor shall protect the primed surface against damage and shall repair all broken spots.]

3.6      CONSTRUCTION OF ASPHALT CONCRETE PAVEMENT

A.         Lay asphalt concrete over the aggregate base in accordance with the SSPWC Section
302-5.5.  The method of proportioning, mixing, transporting, laying, processing, rolling the material, and the standards of workmanship shall conform to the applicable requirements of SSPWC Section 302-5 ASPHALT CONCRETE PAVEMENT.   At no time shall the
coarse aggregate that has segregated from the mix be scattered across the paved mat.

B. A tack coat of emulsified asphalt shall be applied to the first lift of the pavement prior to placing the second lift.  Application shall be in conformance with SSPWC Section 302-
5.4.

C. The Engineer will examine the base before the paving has begun.  The Contractor shall correct any deficiencies before the paving is started.  Roll each lift of the asphalt concrete and  compact  to  95  percent  of  the  density  obtained  with  the  California  Kneading Compactor per California Test 304.   The grade, line, and cross section of the finished surface shall conform to the drawings.

D. Asphalt concrete pavement shall consist of one or more courses of a mixture of paving asphalt  and  graded  aggregate  placed  upon  a  roadbed  or  base,  or  over  existing pavement, as indicated on the Contract Documents.  The mixture shall be placed when it is at a temperature of not less than 250° F nor more than 320° F and shall not be placed onto a wet surface or when the ambient atmospheric temperature is less than 40° F.  All paving or resurfacing shall match the appearance of the existing improvements.  A 4-inch asphalt concrete course shall be placed over an 11-inch aggregate base course unless otherwise shown on the drawings.

E. When asphalt is to be applied over existing pavement, and local irregularities in the existing surface would result in a course of more than the specified thickness, the surface of the existing pavement shall be brought to uniform contour by patching with asphalt concrete thoroughly tamped or rolled until it conforms with the surrounding surface, and a tack coat applied to the entire surface.  Any existing base, surfacing or pavement shall be thoroughly cleaned immediately prior to receiving the plant-mixed surfacing material.

F. Finished pavement, when ready for acceptance, thoroughly compacted and true to cross section, shall not deviate from the designated grade by more than 1/8-inch in 10 feet and shall be free from ruts, depressions and irregularities. The pavement shall be brought to the final grade with a paving machine.  The resulting edge of contact between the new and existing pavement shall be a straight, vertical and neat join line parallel to the trench on each side. New pavement shall not lap over the existing pavement.

G. The base asphalt course mixture shall be placed on the prepared subgrade by means of approved spreading devices in accordance with SSPWC, Subsection 302-5.5.   Where the finished paving area exceeds 5000 square feet or 9 feet in width, the Contractor shall use only a Barber-Green type paving machine.   For smaller areas, the motor grader method for placing the base course may be used unless city permits make the Barber- Green method mandatory.

H. The final asphalt concrete course surface shall be 1-inch thick with ½ inch maximum aggregate grading.   Placing of the final asphalt concrete course shall be done with a Barber-Green type paving machine.

I.          Rolling equipment shall conform to the provisions of SSPWC, Subsection 302-5.6.

3.7      PAVEMENT REMOVAL

A. Pavement  removal  shall  be  in  accordance  with  SSPWC  Subsection  300-1.3  unless otherwise specified herein.

B. Street pavement or pavement within the treatment plants shall be removed within the limits  of  all  construction  excavations  prior  to  excavation.  Surplus  material  shall  be removed as specified in Section 02200, Earthwork.

C. Prior to removing existing surfacing, pavement cuts shall be made as shown on the Contract Documents and as specified herein.   All pavement cuts shall be neat and straight along both sides of the trench or excavation and parallel to its alignment.  The strip of existing AC pavement between an excavation and a gutter face or edge of pavement shall be removed and replaced if less than 3 feet in width.   Where large irregular surfaces are removed, such trimming or cutting shall be parallel to the roadway centerline or at right angles to the same.

D. After backfilling and compaction, final pavement cuts shall be made by saw cutting (unless permit requirements supersede) to a minimum depth of 2 inches at a point not less than 12 inches outside the limits of excavation.

E. Concrete curbs, cross gutters, sidewalks and driveways shall be saw cut to a minimum depth of 1½ inches and at a point not less than 12 inches outside the limits of the excavation.

3.8      TACK COAT

A. All vertical or horizontal hard surfaces, which will be in contact with new pavement, shall be tack coated in accordance with SSPWC, Subsection 302-5.4, and at an approximate rate of 0.05 to 0.10 gallons per square yard.

3.9      SEAL COAT

A. The entire asphalt concrete pavement shall be fog sealed with asphalt emulsion prior to final striping.  The fog sealer shall be applied within 5 calendar days after final asphalt concrete course, at a temperature of 75° F to 130° F, and at a rate of 0.05 to 0.10 gallons per square yard.

B.         Seal coat shall extend over the full width of street width unless otherwise specified.

3.10    EMULSION-AGGREGATE SLURRY

A.         Emulsion-aggregate slurry shall be applied in accordance with SSPWC Subsection 302-4.

3.11    PAVING HEADERS

A. All edges of paving adjacent to earth shall be bounded by 2- x 6-inch net, new rough- sawn redwood headers staked with 2- x 2- x 18-inch redwood stakes, 4 feet on centers. The top edge of headers shall be at the grade of the proposed asphalt surface.  The top of stakes shall be 1-inch below the top of the header.

3.12    ASPHALT CURBS

A. Asphalt curbs, where shown on the Contract Documents, shall be constructed with an automatic curbing machine.

3.13    REPAIRS

A. Areas of new or existing asphalt concrete requiring repair shall be delineated by saw cutting and the asphalt concrete removed, then prime or tack coated, and paved with hot asphalt as specified herein.

3.14    CLEANUP

A. Clean all debris and unused materials from the paving operation.  Clean all surfaces that have been spattered or defaced as a result of the paving operation.  Asphalt or asphalt stains which are noticeable upon surfaces of concrete or materials, which will be exposed to view, shall be promptly and completely removed.  Cleaning shall be done in a manner that will not result in the discharge of contaminated materials into any catch basin or storm drain system.

END OF SECTION