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CITY OF SANTA ANA, CALIFORNIA <br /> <br />STANDARD SPECIFICATION NUMBER 101. <br /> <br />Portland Cement Concrete Base. <br /> <br /> Upon a subgrade prepared as hereinbefore specified, and thoroughly dampened by means <br /> of a spray nozzle, shall be laid a Portland Cement Concrete Base of such width, thickness <br /> and cross-section as shown on the plans. <br /> <br />SECTION 1. <br /> (a) FORMS OR HEADERS. Where the base does not terminate against another <br /> pavement, and along the edges when it does not terminate against a concrete curb or gutter, <br /> and before the final trimming of the subgrade, the Contractor shall set side forms or <br /> headers on a firm foundation true to line and grade. <br /> All timber side forms or headers shall be at least two (2) inches thick and equal in <br /> width to the full thickness of the base, and shall be good sound timber free from warp, <br /> knots, or other imperfections. Their upper edges shall conform to the finished grade and <br /> cross-section of the base. <br /> All joints shall be scabbed with one inch lumber equal in width to the width of the <br /> form and at least eighteen (18) inches long. <br /> The side forms or headers shall be held to the established grade by stakes and braces. <br /> All stakes shall be at least two (2) inches by three (3) inches and twenty (20) inches long <br /> 6r longer if necessar'd, to properly supoprt the headers. Stakes shall be placed immediately <br /> adjacent to either side of the joint and at intervals of not more than thirty (30) inches <br /> therefrom. <br /> Placing of the concrete will not be permitted until the forms are absolutely firfil'nmfl <br /> rigid and capable of resisting all tendency to sl~ring out of line or settle during the <br /> progress of the work. <br /> If metal forms are used, they must be of approved design and equal in width to the <br /> thickness of the base and shall be free from warp or other defects. <br /> SECTION 2. CONCRETE PROPORTIONS. <br /> The concrete shall be mixed in the proportion of one (1) bag of Portland Cement, to <br /> not more than two (2) cubic feet of fine aggregate to not more than four (4) cubic feet <br /> of coarse aggregate, and in no case shall the volume of the fine aggregate be less than <br /> one-half (~) the volume of the coarse aggregate. <br /> The fine aggregate shall consist of concrete sand as hereinbefore specified. <br /> The coarse aggregate shall consist of a Class "A" mixture of either crushed stone o; <br /> ~avel as hereinbefore specified. <br /> The voids in the concrete shall be completely filled with mortar. If voids appear, this <br /> condition shall be remedied by reducing the proportion of coarse aggregate and not by <br /> increasing the amount of fine aggregate. <br /> A cubic yard of concrete in place shall contain not less than six (6) bags of Portland <br /> Cement. <br /> The amount of mixing water used shall be the least that will produce a workable mix. <br /> SECTION $. MIXING CONCRETE. <br /> A mechanical batch mixer shall be used, in which the material, including the water <br /> <br /> <br />