The concrete combined curb and gutter will be constructed after the sub-grade is approximately established.

The trench will be excavated to a width of twenty-eight (28) inches, and to a depth of fourteen (14) inches below the top surface of the gutter. Clean, soft-coal cinders, free from fine ashes and with no clinkers exceeding two (2) inch size will be placed in the trench for the full width thereof, and will be thoroughly wetted and tamped and brought to grade six (6) inches below the proposed gutter surface. The combined curb and gutter will be constructed on this foundation in rigid forms of proper shape and size. Thin metal plates will be used to divide the curb and gutter into approximately 6-foot sections. These plates are to be withdrawn after the concrete has set.

The curb shall be seven (7) inches thick and have a six-inch vertical face, though this latter may be varied if deemed necessary; the gutter shall be six (6) inches thick and have a sixteen (16) inch exposed face. The rear edge of the curb and the outside edge of the gutter shall be rounded to a one-quarter (Y4) inch radius; the front edge of the curb and the junction of the curb and gutter shall be finished with a one (1) inch radius. The face of the curb shall be vertical and the gutter will have a rise of one and onehalf (1 1/2) inches from curb to outside edge.

The body of the curb and gutter will consist of Class I concrete. The concrete shall be well spaded and tamped, and must be free from honey-combing; sufficient water must be used in mixing to insure this result. The exposed faces of the curb and the gutter will be finished with a one-half (1/2) inch surfacing of Portland Cement mortar composed of one part cement and one part clean, sharp, coarse, washed bank sand. To secure proper bond the finish must be applied before the concrete has become too dry, and it must be smoothly trowled to grade and cross-section as described. A brush finish, using a neat cement grout, shall then be applied if considered necessary. The outside of the gutter must be well plastered and free from voids. After the concrete has set and the forms have been removed, the space behind the curb shall be filled with fine earth well tamped.

At driveways the curb and gutter will be constructed as ordered.

At intersecting streets the curb and gutter will be laid to radii shown on the plans.

The price bid per lineal foot for "Concrete Combined Curb and Gutter" shall include both straight and circular sections, and will be for the work complete as above specified, including all labor and materials. Sidewalks disturbed or injured will be repaired in the same manner and to the same extent as specified for "Granite Curb," Items 37 and 38; the work to be done without special compensation.