Specifications for Paving
Scope: Furnish and construct a Full-Depth asphalt pavement structure as specified.
A. General Requirements
- Establishment of Grades: Grades shall be (will be) established by the contractor (owner) and the grade stakes shall be (will be) set to the desired elevation by the contractor (owner). In establishing the grades due allowances shall be (will be) made for existing improvements, proper drainage, adjoining property rights and good appearance.
- Preparation of Subgrade: All-debris, vegetation, or other perishable materials shall be removed from the job site, except for trees or shrubs designated for preservation. The site to be paved shall be graded to the required section and all excess material removed from the location of the work. Material in soft spots shall be removed to the depth required to provide a firm foundation and shall be replaced with a material equal to, or better than, the best subgrade material on the site. The entire subgrade area shall be thoroughly compacted at the lowest moisture content at which a handful of the soil can be molded by a firm closing of the hand. The surface of the subgrade after compaction shall be hard, uniform, smooth and true to grade and cross-section. If specified by the owner or his engineer prior to placing the base course, designated subgrade areas shall be treated with a soil sterilant at the rate specified by the manufacturer to prevent the growth of weeds. If specified, the subgrade shall be primed.
- Thickness of Structure: On the prepared subgrade a plant-mixed asphalt base shall be laid in 1 or 2 course(s) to a compacted thickness as specified in bid. Placing of the plant mixed asphalt surface course shall follow and be laid in a single course to a compacted thickness as specified in bid.
- Tack coat: If specified by the owner (engineer), a tack coat shall be applied at the rate of .10 gallons per square yard.
- Equipment, Materials, and Labor: The contractor shall provide the necessary equipment, materials, and labor to complete the job acceptable to the owner. Variations in the size and amount of equipment will depend on the size of the area being paved.
- Sampling and Testing: If specified by the owner (engineer) the contractor shall furnish for test and analysis representative samples of the materials to be used in the work.
- Smoothness: The surface of the completed work, when tested with a 3m (10-foot) straightedge, shall not contain irregularities in excess of 6mm (1/4 inch).
- Asphalt: The asphalt for the plant mix shall be (type and grade) as specified by the owner (engineer) prior to the letting of the contract. The asphalt material for priming the subgrade shall be (type and grade) as specified prior to the letting of the contract. The asphalt material selected shall meet the requirements of the applicable table in Specifications for Paving and Industrial Asphalts (SS-2), the Asphalt Institute. A certificate of compliance with the specifications of the asphalt will be acceptable.
- Mineral Aggregate: Asphalt Plant-Mix Base and Surface (1) The mineral aggregate for asphalt plant-mix shall consist of coarse aggregate, fine aggregate, and if needed, mineral filler. The coarse aggregate shall be sound, angular crushed stone, crushed gravel, or crushed slag. Uncrushed coarse aggregate may be used in base coarse mixtures if the mixture meets all design criteria. The fine aggregate shall be well graded, moderately sharp to sharp sands. (2) The mineral aggregate and asphalt shall be combined in a mixing plant to meet the following gradations for asphalt concrete base and surface, as specified by the engineer prior to the letting of the contract.
- Spreading Base and Surface Courses: Asphalt Base and Surface
- a) For all areas of more than 840 square meters (1,000 square yards), asphalt base and surface courses shall be spread and struck off with a paver. Any irregularities in the surface of the pavement course shall be corrected directly behind the paver. Excess material forming high spots shall be removed with a shovel or a lute. Indented areas shall be filled with hot mix and smoothed with a lute or the edge of a shovel being pulled over the surface. Casting of mix on such areas shall not be permitted.
- b) If it is impractical to use a paver or spreader box in areas of 840 square meters (1,000 square yards) or less, asphalt base and surface courses may be spread and finished by hand. Wood or steel forms, rigidly supported to ensure correct grade and cross section, may be used. Placing by hand shall be performed carefully to avoid segregation of the mix. Broadcasting of the material shall not be permitted. Any lumps that do not break down readily shall be removed.
- c) Compaction, Asphalt Base and Surface: Rolling shall start as soon as the hot-mix material can be compacted without displacement. Rolling shall continue until thoroughly compacted and all roller marks have disappeared. In areas too small for the roller, a vibrating plate compactor or hand tamper shall be used to achieve thorough compaction.
D. Method of Measurement
- Preparation of Subgrade- Total number of square meters (square yards) of subgrade actually prepared for covering with base material.
- Asphalt Mixture- Total number of tons of asphalt mixture actually incorporated into the work.
E. Basis of Payment
Basis of Payment: Payment will be in full compensation for furnishing, hauling, and placing materials, for rolling, and for all labor and use of equipment, tools, and incidents necessary to complete the work in accordance with these specifications.
The contractor shall guarantee in writing the workmanship and materials of the completed pavement for a period of (1) one year.
NOTES TO THE OWNER (ENGINEER)
- This specification is applicable for such small paving jobs as:
- Parking Areas 4200 square meters (5,000 square yards) or less
- Service Stations
- Bicycle Paths
- Golf Cart Paths
- Full-Depth asphalt pavements are recommended for greater strength and durability.
- Establishment of Grades- If the contractor is to establish the grades, delete “will bell and “owner” wherever they appear in the first sentence. If the owner is to establish the grades, delete “shall bell and “contractor”.
- Tack Coat- From 0.25 to 0.7 litre/square meters (0.05 to 0.15 gallons/square yards) of diluted SS-1, SS-1h, CSS-1, or CSS-1h is recommended. The asphalt emulsion should be diluted with equal parts of water.
- Equipment- If the job is under the supervision of an engineer, the engineer should approve those pieces of equipment applicable to the job to which the specification will apply.
- Mineral Aggregate- Asphalt Plant-Mix Base and Surface- Ashphalt mixes meeting the requirements of ASTM Standard Specification D 3515 are recommended. Asphalt mixes specified by local public agencies may be used if they have a satisfactory performance. Contact an Asphalt Institute Engineer for information on local mixes.