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shall be placed by equipment which will prevent segregation or loss of ingredients. The stream of concrete <br /> shall not be allowed to separate by permitting it to fall freely over rods,spacers,or other embedded <br /> materials. <br /> All concrete placed in walls exceeding 6'in height shall be spouted or"tremmied"so that the maximum <br /> free fall shall be 5'. <br /> Concrete shall be placed in continuous layers of approximately 12"and the total elapsed time between <br /> placing of successive layers shall not exceed 30 minutes. <br /> All wood blocking,spreaders,and screens shall be removed as the concrete is poured and before the <br /> concrete sets. <br /> Form oil shall be approved for potable water applications. <br /> 3.03 CONSTRUCTION JOINTS <br /> The location of all construction joints will be subject to the acceptance of the Engineer. The surface of all <br /> construction joints shall be power washed until thoroughly clean and all latence and standing water <br /> removed. Clean aggregate shall be exposed by abrasive blast cleaning. Wire brushing and air water jets <br /> may be used while concrete is fresh provided results are equal to abrasive blast cleaning. Construction <br /> joints shall be keyed at right angle to the direction of shear. Except where otherwise shown on the plans, <br /> keyways shall be at least 1-1/2"in depth over at least 25%of the area of the section. <br /> 3.04 CURING AND PROTECTION <br /> A. General <br /> Beginning immediately after placement,concrete shall be protected from premature drying, <br /> excessively hot or cold temperatures,and mechanical injury,and shall be maintained with minimal <br /> moisture loss at a relatively constant temperature for the period necessary for hydration of the <br /> cement and hardening of the concrete. The materials and methods of curing shall be subject to <br /> acceptance by the Engineer. <br /> For concrete surfaces not in contact with forms,one of the following procedures shall be applied <br /> immediately after completion of placement and finishing: <br /> 1. Ponding or continuous sprinkling. <br /> 2. Application of absorptive mats or fabric kept continuously wet. <br /> 3. Application of sand kept continuously wet. <br /> 4. Continuous application of steam(not exceeding 150'F or mist spray). <br /> 5. Application of waterproof sheet materials,conforming to"Specifications for Waterproof <br /> Sheet Materials for Curing Concrete"(ASTM C171). <br /> 6. Application of other moisture retaining covering as accepted. <br /> 7. Application of a curing compound conforming to"Specifications for Liquid Membrane <br /> Forming Compounds for Curing Concrete"(ASTM C309)and approved for potable <br /> water applications. The compound shall be applied in accordance with the <br /> recommendations of the manufacturer immediately after any water sheen which may <br /> develop after finishing has disappeared from the concrete surface. It shall not be used on <br /> any surface against which additional concrete or other material is to be bonded unless it is <br /> Section 03310-Page 6 of 8 9/17 <br />