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9.8 Adhesives for water-stop shall be applied in a thin, uniform coat with no <br />gaps. The water-stop shall than 6e firmly pressed into the adhesive after <br />the adhesive has dried to a tacky condition, 15 to 30 minutes. Concrete <br />shall then be placed within 12 hours after installation of the water-stop. <br />The water-stop shall be protected from water and from displacement until <br />concrete placement has occurred. <br />9.9 Water-stops shall be measured and cut to the exact lengths required with <br />no splices. <br />10 DEPOSITING CONCRETE <br />10.1 GENERAL <br />Acceptable placing practices to obtain durable and watertight concrete are <br />given in ACI 304R. Concrete shall be conveyed and placed as rapidly as <br />practicable, either by manual or mechanical means that will prevent the <br />segregation and/or loss of ingredients. <br />10.2 PREPARATION <br />Before placing concrete, all dirt, debris, water, and ice shall be removed <br />from forms, trenches, and excavations. Any flow of water into an <br />excavation shall be diverted through proper side drains to a sump or <br />removed by other approved methods which will avoid the washing of <br />freshly deposited concrete. <br />10.3 PLACING METHODS <br />Concrete shall be deposited continuously in horizontal layers in a manner <br />that will prevent the displacing of reinforcement and the accumulation of <br />concrete on the forms or reinforcement. <br />10.3.1 DROPPING CONCRETE <br />The concrete shall not be allowed to drop freely more than <br />four feet 14'1. Drops greater than four feet 14'1 shall be <br />accomplished by a confining device acceptable to the Engi- <br />neer. <br />10.3.2 CHUTING <br />Chuting of concrete shall be permitted only upon accep- <br />tance of the methods by the Engineer. Chutes shall be of <br />rounded cross-section to avoid the accumulation of <br />concrete in corners. The slope shall be steep enough to <br />permit flow without requiring a slump greater than that <br />specified or required for placement (slope usually one (11 <br />vertical to two (21 or two and one-half (2yg horizontall. All <br />chutes and hoppers shall be thoroughly cleaned before and <br />after each run. All wash water and debris shall be <br />SPEC B -CONCRETE <br />PAGE 14 <br />