Placement and Finishing. The concrete sidewalk slabs shall be placed in alternate slabs 30 feet in length except as otherwise ordered. The slabs for sidewalks shall be separated by transverse preformed expansion joint fillers and sealer ½ inch thickness, as specified. Concrete placement shall comply with the requirements as specified under CONCRETE WORK for mixing and placing concrete and as herein specified. Concrete shall not be placed until forms have been checked for line grade. Unless otherwise specified, concrete shall be 4000 psi and shall meet MHD Standard Specifications as specified in Section M4.02.00 of the “Standard Specifications for Highways and Bridges,” Commonwealth of Massachusetts, Department of Public Works, 2023 Edition, as amended and corrected. Subbase shall be moistened as necessary to provide a uniform damp condition at the time of concrete placement. Concrete shall be placed in a continuous operation using methods which prevent segregation of mix. If placement is interrupted for more than ¼ hour, the Contractor shall place a construction joint. Construction joints shall be placed at score lines only, using a standard metal key-way section form. After striking off and consolidating the concrete, the contractor shall smooth the surface by screening and floating. The surface shall then be checked for trueness and troweled to remove irregularities. After troweling, contraction joints shall be scored and edging done. When excess moisture or surface sheen has disappeared, the surface shall be broomed lightly at right angles to the curb or as directed. Tooling of edges and contraction joints shall then be repeated to remove broom finish in these areas. The surface of all concrete sidewalks shall be uniformly scored with contraction joints into block unit of areas not more than 36 square feet as directed. The depth of the scoring shall be 1 inch.
