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<br />03300 - 13/22 <br />A. Concrete shall be conveyed from the mixer to the place of final deposit by methods <br />that will prevent separation or loss of material. <br />B. No aluminum materials shall be used in conveying any concrete. <br />C. Ends of chutes, hopper gates, and all other points of concrete discharge throughout <br />the CONTRACTOR'S conveying, hoisting, and placing system shall be designed and <br />arranged so that concrete passing from them will not fall separated into whatever <br />receptacle immediately receives it. Conveyor belts, if used, shall be of a type <br />acceptable to the ENGINEER. Chutes longer than 50 feet will not be permitted. <br />Minimum slopes of chutes shall be such that concrete of the indicated consistency <br />will readily flow in them. If a conveyor belt is used, it shall be wiped clean by a <br />device operated in such a manner that none of the mortar adhering to the belt will be <br />wasted. All conveyor belts and chutes shall be covered. <br />D. Pumping: <br />1. If the pumped concrete does not produce satisfactory end results, the <br />CONTRACTOR shall discontinue the pumping operation and proceed with the <br />placing of concrete using conventional methods. <br />2. The pumping equipment shall have 2 cylinders and be designed to operate <br />with one cylinder in case the other one is not functioning. In lieu of this <br />requirement, the CONTRACTOR may have a standby pump on the Site during <br />pumping. <br />3. The minimum diameter of the hose conduits shall be in accordance with ACI <br />304. <br />4. Pumping equipment and hose conduits that are not functioning properly shall <br />be replaced. <br />5. Aluminum conduits for conveying the concrete shall not be permitted. <br />6. Concrete samples for slump, air content, and test cylinders will be taken at the <br />placement end of the hose. <br />3.04 DELIVERY: <br />A. Ready-mixed concrete shall be batched, mixed, transported and delivered in <br />accordance with these specifications and ASTM C 94 including the following <br />supplementary requirements. <br />1. Concrete shall be discharged within 1-1/2 hours from the time concrete was <br />mixed, if centrally mixed, or from the time the original water was added, if <br />transit-mixed or before the drum has been revolved 300 revolutions, whichever <br />is first. <br />2. Truck mixers and their operation shall be such that the concrete throughout the <br />mixed batch as discharged is within acceptable limits of uniformity with respect <br />to consistency, mix, and grading. If slump tests taken at approximately the 1/4 <br />and 3/4 points of the load during discharge give slumps differing by more than <br />one-inch when the required slump is 3-inches or less, or if they differ by more <br />than 2-inches when the required slump is more than 3-inches, the mixer shall <br />not be used on the WORK unless the causative condition is corrected and <br />satisfactory performance is verified by additional slump tests. Mechanical <br />details of the mixer, such as water measuring and discharge apparatus, <br />condition of the blades, speed of rotation, general mechanical condition of the