A. 
Concrete strength. Concrete for curbs, gutters, sidewalks and driveway aprons shall be constructed with air-entrained concrete with a minimum twenty-eight-day compressive strength of 4,000 psi.
B. 
Joint filler. Joint filler shall be a cellular compression material conforming to the requirements therefor of the Standard Specifications of the New Jersey State Highway Department as amended and revised to date.
Concrete curb shall be constructed in accordance with Division 5, Section 5, of the state specifications and concrete sidewalks shall conform to Division 5, Section 8, except as herein amended.
The contractor shall make all necessary excavations or embankments for the construction and disposing of surplus materials. No filling shall be done below the proposed curb or gutter except when absolutely necessary, in which case, such fill shall be made with clean sand or approved gravel and thoroughly tamped before concrete is laid thereon. All soft spots shall be thoroughly tamped before concrete is laid thereon or if necessary, soft or spongy material shall be removed and clean sand or gravel refilled in its place.
Within 72 hours after curbing is completed and forms removed, the contractor shall backfill to the top of the curb in back and to the established gutter grade in front. Backfill shall be made with the materials excavated, except that any large or frozen lumps, wood, boulders or other foreign matter shall be removed before placing. Backfill shall be thoroughly compacted.
Forms for concrete may be of lumber or steel. They shall be straight and of sufficient strength to prevent warping or bulging and to retain the concrete accurately in position. All mortar and dirt shall be removed from forms which have been previously used. Forms shall be well staked to the proposed lines and grades, and their upper edges shall conform to the finished surface of the curb. All forms shall be thoroughly wetted immediately before concrete is deposited against them. Curved forms shall be used for the construction of all radius curb.
Concrete construction, including curing, shall conform to the applicable requirements of the section on concrete structures contained elsewhere herein. The concrete shall be tamped, and spaded or vibrated so that the forms are completely filled, the concrete thoroughly compacted and mortar is flushed to the face and top.
Expansion joints shall be provided at intervals of 20 feet or when new construction abuts existing construction. The expansion joints shall be filled with one-half-inch thick cellular compression material to within 1/2 inch of the top and face of the curb and to within 1/4 inch of the top of the gutter. Dummy joints shall be provided midway between expansion joints.
Expansion joints 1/2 inch wide shall be provided at intervals of 20 feet and where the new paving abuts curb or old work. The expansion joints shall be filled with one-half-inch thick cellular compression material to within 1/4 inch of the top of the paving. For sidewalks, surface grooves shall be cut with an approved tool at least one-quarter-inch thick at right angles to the line of the sidewalk and at intervals equal to the width of the sidewalk. Where new work abuts existing sidewalk, the surface grooves shall be spaced to conform to the lines of the abutting walk. All surface edges shall be rounded to a radius of 1/2 inch.
Before initial set, the top of the curb and gutter shall be finished with a wood float to an even, smooth and dense surface. As soon as the forms can be removed, the face of the curb shall be given the same finish. Exposed edges shall be neatly rounded to a radius of 1/2 inch. The finished curb shall not vary from the required grades, lines, dimensions and curvatures by more than 1/4 inch at any point. Completed work shall be protected from traffic and the elements and be thoroughly wetted and kept moist for at least one day. Damaged, broken or cracked work shall be replaced by the contractor.
The finish shall be with a wood float, followed by brooming. Exposed edges shall be neatly rounded to a radius of 1/2 inch. The concrete shall be cured as provided elsewhere herein.
A. 
No concrete shall be poured between December 1 and March 1 of each year without prior written permission of the engineer.
B. 
All concrete poured during this period shall conform to the procedures specified in the New Jersey State Highway Department Standard Specifications except as otherwise directed by the engineer.