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SPECIFICATION NUMBER: <br /> Clitl axMolj/bdenuo, CONCRETE CONSTRUCTION 03 30 00 SPE <br /> A Freeport-McMoRan Company TECHNICAL SPECIFICATION PROJECT NAME: <br /> CAVR Shaft Closure Project <br /> accomplished immediately after the concrete has been deposited in the <br /> forms. Vibrators should not come in contact with forms, reinforcements or <br /> embedded items. <br /> M. Retempering <br /> 1. Water shall not be added to mixed batches of concrete to increase the slump <br /> without specific approval of the Engineer or Owner. When batches <br /> delivered to the job show an unduly low slump (as might occur during hot <br /> weather) consideration shall be given to the use of retarders. <br /> N. Bonding <br /> 1. Concrete on which other concrete is placed shall be either still plastic or <br /> thoroughly hardened,but not in a semi-hardened state that may be disrupted <br /> and weakened by the added load and the jarring due to placement of <br /> �. additional concrete. <br /> t <br /> 2. To provide bond between successive lifts of concrete, the exposed surface <br /> F <br /> of the hardened concrete shall be cleaned and roughened,without loosening <br /> the embedded aggregate. Brooms or air-water jets shall be used after the <br /> start of initial setting of the concrete. Sand-blasting or air-tooling shall be <br /> employed after the concrete has hardened. In all cases, the surface film and <br /> E laitance or diluted paste shall be removed and a reasonably high percentage <br /> of aggregate exposed. Immediately before the new concrete is placed, the <br /> old surface shall be clean, damp and free from standing pools of water. <br /> 3. Batches of neat cement or of mortar having about the same proportion of <br /> cement to sand as used in the concrete, or as otherwise specified herein, <br /> shall be deposited and well brushed in,just ahead of the new concrete. <br /> O. Concrete Finishes <br /> 1. Use of neat cement to absorb excessive surface water is prohibited. <br /> Application of additional water to facilitate finishing is prohibited. <br /> E' <br /> 2. "Float Finish" shall be accomplished by wood, cork, or metal floats or by a <br /> ` finishing machine. After the concrete has been properly placed, vibrated, <br /> f and roughly leveled, it shall be screed off to the proper elevation. Coarse <br /> aggregate shall be tamped below the surface. After screeding and tamping <br /> of coarse aggregate, the surface shall be made uniform by means of a bull <br /> float. After floating, the surface shall be tested for uniformity by use of a <br /> straight edge. Variations from desired finished elevations shall not exceed <br /> 1/4 inch in 10 feet. <br /> F <br /> 114-910345 CONCRETE CONSTRUCTION <br /> Climax CAVR Shaft Closure Project 03 30 00 SPE-19 <br />