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.