2.13 Overlays and Inlays
a. All AC pavement overlays shall include non-woven fabric specifically designed for use with AC pavement.
b. The standard minimum overlay thickness shall be 2-inches. In no case shall the overlay thickness be less than 1½-inches. This minimum thickness shall be increased as necessary to provide the required cross slopes, with smooth transitions between all variations in cross slope.
c. Design of overlays shall be based on an analysis of the existing pavement condition by a registered professional engineer experienced in the design of pavements, and shall result in the minimum practical design life as specified. Unless otherwise approved by the Director, testing of the existing pavement shall include the following as a minimum.
1) Coring of the street at maximum 50 foot intervals to establish the thickness and condition of existing pavement and aggregate base.
2) Non-destructive falling weight deflectometer tests on the existing pavement proposed for overlay.
3) Preparation of an engineering analysis of overlay thickness required to provide the specified design life with all anticipated truck traffic.
d. Areas of existing pavement and baserock which exhibit deflection or alligator cracking or have otherwise failed shall be excavated and replaced with new compacted baserock and AC pavement prior to the overlay. Baserock and AC pavement repair thicknesses shall match standard section thicknesses. All cracks greater than 1/8-inch in width shall be cleaned out and filled with an asphalt emulsion slurry and sand, or other method approved by the City Engineer. All crack sealing, skin patching and plugging of digout areas must be approved by the Director prior to the placement of the final fabric and overlay.
e. Overlay fabric shall be Petromat as manufactured by Amoco Fabrics & Fiber Company, or approved equal. Hot oil tack coat (PBA-5 or approved equal) shall be used prior to placement of the overlay fabric. Use of emulsion tack coats shall be prohibited.
f. Asphalt overlays shall include grinding as required to allow the minimum overlay thickness at existing paving, catch basins, gutter pans and other structures which cannot be raised to grade. Unless otherwise approved by the City Engineer, all existing manholes, valve boxes and other structures shall be raised to grade before the overlay.
g. Vertical curb clearance shall be greater than 4” otherwise an inlay is required.