ASPHALTIC CONCRETE PAVING SECTION

Transcription

1 SECTION PART 1: GENERAL 1-01 SECTION INCLUDES: A. Asphaltic concrete paving. B. Seal Coat RELATED SECTIONS: A. Division 31 Earthwork B. Section Aggregate Base Course. C. Section Soil Sterilization. E. Drawings and general provisions of Contract, including General and Supplementary Conditions and Division - 01 Specifications sections, apply to the work of this section REFERENCES: A. SSCDOT Standard Specifications, Department of Transportation, State of California (Caltrans), latest edition, except for references to method of payment, and references to any state furnished materials QUALITY ASSURANCE: A. Perform work in accordance with SSCDOT. B. Mixing Plant: Conform to SSCDOT SUBMITTALS: A. Submit under provisions of Section B. Certificates of compliance for materials. C. Load tags for delivered material

2 1-06 COORDINATION: A. Coordinate with other work, including subgrade preparation and soil sterilization ENVIRONMENTAL REQUIREMENTS: A. Do not place asphalt-concrete when atmosphere temperature is less than 50 degrees F, or surface is wet or frozen. PART 2: PRODUCTS 2-01 MATERIALS: A. Paint Binder: In accordance with SSCDOT, Asphaltic Emulsions. B. Asphalt Concrete: Type B in accordance with SSCDOT, ½ inch maximum aggregate (medium). The asphaltic concrete shall be compacted to an average relative compaction of 97 percent, with no single test value being below a relative compaction of 95 percent based on a 50 blow Marshall maximum density. Use asphalt binder performance grade PG The bitumen ratio shall be no less 3 and no more than 7 pounds of asphalt per 100 pounds of dry aggregate. C. Seal Coat: Asphalt based seal coat shall be Tuf-Cote as manufactured by Industrial Asphalt, Irwindale, California, or approved equal. D. Seal Coat, Type 2: Reference Section 37 of the SSCDOT. E. Pavement Fabric: A needle-punched nonwoven fabric weighing a minimum of 4.1 oz. per square yard, which, when embedded in a field applied asphalt cement tack coat becomes an asphalt saturated fabric membrane. The fabric to meet a minimum elongation specification of 50% in a grab tensile strength test and most milled surface configurations would only mobilize no more than 5 to 20% of the fabric elongation. The fabric is manufactured to resist tears (4500 lbf), puncture ( 6000 lbf) and burst strength (28,700 psf).during construction. F. Stabilization and Soil Reinforcement Fabric: Geosynthetic fabric shall be Mirafi HP 570 as manufactured by TenCate Geosynthetics Americas, Pendergrass, Georgia, or approved equal

3 PART 3: EXECUTION 3-01 EXAMINATION: 3-02 BASE: A. Verify that subgrade has been compacted to required relative compaction and is dry. B. Verify elevations of base are correct. C. Verify the subgrade has been sterilized per A. Furnish and install aggregate base course per Section INSTALLATION OF GEOSYNTHETIC FABRIC: A. Install geosynthetic fabric per manufacturers recommendations and as shown on drawings PREPARATION PAINT BINDER: A. Apply paint binder (tack coat) to existing asphalt-concrete or concrete surfaces which will be in contact with asphalt concrete surfacing. B. Rate of application for all surfaces against which asphalt concrete is to be placed shall be no less than 0.02 and no more than 0.05 gallons per square yard. All vertical concrete surfaces which will be in contact with asphalt concrete surfacing and all areas now in place which will be covered with new surfacing materials and feathering operations shall be coated with a paint binder applied at the rate of 0.05 gallons per square yard. C. Increase the rate of application 10% to 15% for milled or uneven asphalt concrete surfaces. D. Increase the rate of application as recommended by the pavement fabric manufacturer to saturate the fabric prior to the asphalt concrete overlay INSTALLATION OF PAVEMENT FABRIC FOR ASPHALT CONCRETE OVERLAY A. Apply paint binder onto milled pavement surface and pavement surface to receive asphalt concrete overlay

4 B. Place pavement fabric over the paint binder. The fabric should be broomed or pneumatically rolled into place. When placing a paving fabric on a milled surface, the surface needs to be clean and dry. Brooming and/or air blowing will be required to eliminate dust and cuttings left on the pavement surface. C. Apply tack coat to saturate fabric INSTALLATION OF ASPHALTIC CONCRETE: A. Install in conformance with SSCDOT, Asphalt Concrete. B. Thickness As shown on construction plans: Asphaltic concrete shall be laid to the thickness designated on the Plans. The Contractor shall lay the asphaltic concrete to a depth required to insure that, after compaction, the in place compacted thickness is equal to or greater than the specified plan thickness. The maximum layer of asphalt concrete thickness shall not exceed 3 inches. C. Asphalt type: PG D. Compaction Equipment In accordance with Section 39, SSCDOT INSTALLATION OF SEAL COAT ON NEW PAVEMENT AREA: A. A minimum of 21 days waiting period is required for new pavement to receive seal coat. B. Immediately prior to applying the sealer, the surface shall be cleaned of all loose material which might adversely affect bonding of the sealer. C. A prime coat of SS-1 asphalt emulsion diluted with water, to 5 parts water to 1 part asphaltic emulsion, shall be applied to all existing (not new) pavement surfaces at a rate of application of 0.05 to 0.10 gallon of diluted primer per square yard. D. Following the prime coat, two coats of asphalt based seal coat shall be applied. The first coat shall have added to it a silica sand mineral filler, which has passed a 50-mesh screen, at a rate of 2 to 3 pounds per 1 gallon of concentrated sealer. When the first coat is dry enough to walk on without picking the material up, a second coat shall be applied without mineral filler. If the manufacturer indicates that the product may be diluted, it may be diluted with no more than 20 percent by volume clean fresh water with the prior approval of the Engineer. The total application rate shall be a minimum of 35 to 45 gallons of undiluted product per 1,000 square feet, as directed by the Engineer. The finished surface shall be

5 smooth and uniform in appearance. If existing depressions are such that aggregate still protrudes after the second coast of asphalt based sealer has been applied, the Contractor shall apply a third coat when so directed by the Engineer. 1. Seal Coat (for new pavement) a minimum of 20 gallons of undiluted product per 1,000 square feet, as directed by the Engineer. E. Protect sealed surface until it is cured INSTALLATION OF SEAL COAT ON EXISTING PAVEMENT AREA: A. Immediately prior to applying the sealer, use power sweepers and blowers to clean the surface of all loose material which might adversely affect bonding of the sealer. B. Apply emulsion primer on the pavement surface that has gasoline, grease, and oil stains. C. Fill all small cracks with crack filler in accordance with the manufacturers recommendations. D. Any cracks 1/2 in depth or/and ¼ in width, potholes and depressed area, thoroughly clean and place type B(No. 4 Max) Asphalt concrete cold patch primer to sealing. E. A prime coat of SS-1 asphalt emulsion diluted with water, to 5 parts water to 1 part asphaltic emulsion, shall be applied to all existing (not new) pavement surfaces at a rate of application of 0.05 to 0.10 gallon of diluted primer per square yard. F. Following the prime coat, two coats of asphalt based seal coat shall be applied. The first coat shall have added to it a silica sand mineral filler, which has passed a 50-mesh screen, at a rate of 2 to 3 pounds per 1 gallon of concentrated sealer. When the first coat is dry enough to walk on without picking the material up, a second coat shall be applied without mineral filler. If the manufacturer indicates that the product may be diluted, it may be diluted with no more than 20 percent by volume clean fresh water with the prior approval of the Engineer. The total application rate shall be a minimum of 35 to 45 gallons of undiluted product per 1,000 square feet, as directed by the Engineer. The finished surface shall be smooth and uniform in appearance. If existing depressions are such that aggregate still protrudes after the second coast of asphalt based sealer has been applied, the Contractor shall apply a third coat when so directed by the Engineer

6 G. Protect sealed surface until it is cured. H. Apply seal coat, Type 2 per Section 37 of the SSCDOT TOLERANCES: A. Flatness: Maximum variation of ¼ inch measured with 10-foot straight edge or no greater than 1/8 inch below the bottom of the straight edge. B. Scheduled Compacted Thickness: Within ¼ inch FIELD QUALITY CONTROL: A. Field inspection and testing will be performed by Section B. During the curing period and before the application of the seal coat, a water test is to be performed by the Contractor in the presence of the Engineer to determine if there are any low ponding areas or bird baths on the new asphalt concrete pavement. A liberal amount of water is to be applied to the entire new pavement surface by a water truck or from a fire hose. If an area retains depth of 1/8 or more of water, the area will be marked at the water s edge and is to be designated as the Limits of Repair. The Contractor shall apply an asphalt skin patch to fill the low area to the designated Limits of Repair. Perform second water test to the repaired area to verify that the area will properly drain and will not retain water PROTECTION: A. Immediately after placement, protect pavement from mechanical injury. END OF SECTION