(A) Description and general requirements.
(1) This item shall consist of furnishing all materials and performing all construction procedures required to build an asphalt pavement, on prepared and approved subgrade, conforming to the requirements of these specifications and to the pavement designs shown on the approved plans. It may include any, or all, but is not necessarily limited to, materials and methods specified under this section.
(2) Asphalt pavement shall consist of an asphalt concrete surface course or courses, constructed on a base course or courses or subbase course designed in compliance with the requirements of App. B, § 5, of this chapter.
(3) Successive layers of the pavement shall be offset from the edge of the underlying layer a distance equal to the course thickness of the lower layer, except when abutting existing construction. When the asphalt layers of the pavement abuts a building foundation, barrier curb or similar vertical surface, the abutting surface shall be heavily painted with asphalt prior to construction of the asphalt course. The surface course shall be finished one-fourth inch above adjacent flush construction to permit proper compaction.
(B) Materials and construction requirements.
(1) Asphalt concrete surface course. Asphalt concrete surface course materials and construction shall conform to the current requirements of the state’s Department of Transportation, Bureau of Highways for asphalt concrete surface, Class I. Surface course mixture composition may conform to the requirements of either surface course I or II, as set forth in App. B, § 6, Table 5, of this chapter. Minimum asphalt concrete surface course thickness shall be as stated in App. B, § 6, Table 6, of this chapter.
(2) Asphalt concrete base course.
(a) Asphalt concrete base course materials and construction shall conform to the current requirements of the State Department of Transportation, Bureau of Highways, specifications for asphalt concrete base course, Class I, except as noted herein.
(b) Composition requirements of the mixture shall conform to the gradation limits for asphalt concrete base course I or II, set forth in App. B, § 6, Table 5, of this chapter. Asphalt concrete used shall fall within the range shown and shall be approved by the inspector.
(c) Uncrushed gravel and natural sand may be used as aggregate provided all other requirements of the specifications are complied with.
(3) Crushed aggregate base course.
(a) Description. Crushed aggregate base course, when provided for in the approved structural design of the pavement, shall consist of a granular layer constructed on prepared subgrade or subbase in accordance with these specifications and in conformity with the approved dimensions, lines, grades and cross- sections.
(b) Materials and construction methods. Crushed aggregate base course shall conform to all the current requirements for materials and construction methods of the State Department of Transportation for dense graded aggregate base course; except that, 100% crushed gravel (at least one major crushed face on all aggregate coarser than a No. 4 sieve) may be used. When use of a crushed gravel is elected, aggregate shall conform to all other requirements of the referenced specification. In addition, fine aggregate (finer than a No. 4 sieve) shall consist of angular particles produced from crushing larger gravel particles. If necessary, fine aggregate produced from crushed stone may be blended, by approved mechanical methods, at the mixing plant to produce the required gradation.
(4) Granular subbase course.
(a) Description. Subbase, when provided for in the approved structural design of the pavement, shall consist of a granular layer conforming to the following material and construction specifications.
(b) Aggregate requirements. Material for granular subbase may be crushed or uncrushed aggregate containing no more than a total of 5% deleterious substances, such as, but not limited to, shale, soft particles, coal or lignite. The subbase aggregate shall have a sand equivalent, as determined from AASHO Designation T-176, of not less than 25. That portion of the aggregate passing a No. 40 sieve shall have a liquid limit of not more than 25 and a plasticity index of not more than six when tested in accordance with AASHO Designations T-89 and T-91, respectively. Gradation of granular subbase shall be reasonably uniform and consistent and shall conform to the gradation requirements set forth in App. B, § 6, Table 5, for this chapter for asphalt treated base III or IV.
(c) Construction of subbase. Subbase shall be constructed on completed and approved subgrade to the required dimensions, grade and cross-section. Aggregate shall be spread by mechanical spreaders, or other equipment approved by the inspector; capable of spreading material uniformly in layers not exceeding six inches compacted depth. Subbase shall be compacted with approved equipment to not less than 100% AASHO Designation T-99 density.
(5) Asphalt prime coat.
(a) Asphalt prime coat shall be applied to the surface of granular courses on which asphalt base or surface courses will be constructed.
(b) Asphalt prime shall conform to the state’s Department of Transportation requirements for cutback asphalt emulsion primer type L. Prime shall be applied to the surface of granular base course at a rate of 0.20 to 0.40 gallons per square yard, as directed by the inspector, in conformance with requirements of the referred to specification.
(6) Asphalt tack coat.
(a) Tack coat shall consist of SS-1h, meeting the current requirements of the state’s Department of Transportation.
(b) It shall, directed by the inspector, be diluted with equal parts of water. Application equipment and procedure shall conform to the requirements of the state’s Department of Transportation for tack coats. Tack coat shall be applied to the surface of asphalt courses that have become dusty or dry from traffic use before the subsequent course is constructed or in other circumstances when the inspector so directs.
(1984 Code, Ch. 157, App. B, § 4) (Ord. O-86-78, passed 8-17-1978)