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SPECIFICATION NUMBER: <br /> n Climax Molybdenum CONCRETE CONSTRUCTION 03 30 00 SPE <br /> AFreeporf-McMoRanCornpaoy TECHNICAL SPECIFICATION PROJECT NAME: <br /> CAVR Shaft Closure Project <br /> there will be no contamination of the concrete or separation of the <br /> ingredients. After this operation, the entire equipment shall be thoroughly <br /> cleaned. <br /> 4. Concrete shall be placed in the forms in uniform layers as nearly as <br /> practicable in final position. It shall not be allowed to fall freely more than <br /> 5 feet in unexposed work, nor more than 3 feet in exposed work. Drop <br /> chutes shall be available in sufficient number so the concrete placement can <br /> be made in horizontal layers with little lateral concrete movement in the <br /> forms. <br /> 5. Concrete layers shall not exceed 2 feet in thickness and shall be thoroughly <br /> consolidated before the succeeding layer is placed. Timing of placement <br /> shall be such that each succeeding layer is placed before the preceding layer <br /> has reached its initial set. <br /> L. Consolidation <br /> ` 1. During and immediately after placing, concrete shall be lightly vibrated and <br /> worked to provide thorough consolidation around reinforcement,embedded <br /> items, and into corners of forms. It shall be consolidated with immersion- <br /> type vibrators having frequencies in the range of 3,600 to 13,000 vibrations <br /> per minute. External vibrators mounted on or held against the forms shall <br /> not be permitted. <br /> 2. After a level surface has been attained by inserting the vibrator into centers <br /> f of high concrete points left during depositing, the vibrator should be <br /> inserted vertically at uniform spacings of about 12 to 24 inches, such that <br /> the area visibly affected overlaps previously vibrated material by a few <br /> inches. <br /> 3. The vibrator should penetrate rapidly through the full depth of each new <br /> concrete layer and about 6 inches into any preceding fresh layer. The <br /> vibrator should be held in such position until consolidation is considered <br /> adequate (5 to 15 sec). The vibrator should then be withdrawn slowly at a <br /> rate of about 3 inches per second. Concrete should move back into the space <br /> vacated by the vibrator. To prevent segregation of mix, vibration shall be <br /> continued only long enough to accomplish thorough consolidation and <br /> complete embedment of the reinforcement and fixtures. <br /> 4. Vibrators shall not be used as a means of moving concrete to a desired <br /> placement area. This action shall be accomplished by correct initial <br /> l placement augmented by the use of hand shovels. The Contractor shall <br /> provide a sufficient number of vibrators so that consolidation can be <br /> d <br /> 114-910345 CONCRETE CONSTRUCTION <br /> Climax CAVR Shaft Closure Project 03 30 00 SPE-18 <br /> E_ <br />