Section 03300 Cast-in-Place Concrete

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03300 - 11/22 PART 3 - EXECUTION 3.01 PROPORTIONING AND MIXING: A. Proportioning of the mix shall conform to the requirements of Chapter 3 "Proportioning" of ACI 301. B. Mixing shall conform to the requirements of Chapter 7 of ACI 301. C. Slumps shall be as indicated herein. D. Retempering of concrete or mortar that has partially hardened shall not be permitted. 3.02 PREPARATION OF SURFACES FOR CONCRETING: A. General: Earth surfaces shall be thoroughly wetted by sprinkling prior to the placing of any concrete, and these surfaces shall be kept moist by frequent sprinkling up to the time of placing concrete thereon. The surface shall be free from standing water, mud, and debris at the time of placing concrete. B. Vapor Barrier 1. Vapor Barrier shall be installed under on-grade building floor slabs of occupiable (non-hydraulic) structures and at other locations indicated. 2. Base shall be leveled, compacted, and tamped per SECTION 02200 Earthwork. Remove sharp edges, projection materials and roughness that might penetrate vapor barrier. Install barrier with width parallel with the direction of the pour of the concrete. 3. Place, protect, and repair defects in sheet according to ASTM E 1643, and the manufacturer's written instructions. Seams shall be lapped and sealed in accordance with ASTM E 1643. 4. The CONTRACTOR shall exercise care to avoid puncturing or tearing the vapor barrier during installation. Patch punctures and tears as they occur. C. Joints in Concrete: 1. All joints shall be installed where indicated on the Drawings or where otherwise approved by the Engineer. The surface of the construction joint shall be rough and prior to placement shall be cleaned and moistened with water. 2. Concrete surfaces upon or against which concrete is to be placed, where the placement of the concrete has been stopped or interrupted so that, as determined by the ENGINEER, the new concrete cannot be incorporated integrally with that previously placed, are defined as construction joints. The surfaces of horizontal joints shall be given a compacted, roughened surface for good bonding. Except where the Drawings call for joint surfaces to be coated, the joint surfaces shall be cleaned of all laitance, loose or defective concrete, foreign material, and be roughened to a minimum 1/4-inch amplitude. Such cleaning and roughening shall be accomplished by hydroblasting or sandblasting (exposing aggregate) followed by thorough washing. Pools of water shall be removed from the surface of construction joints before the new concrete is placed. 3. After the surfaces have been prepared, all approximately horizontal construction joints shall be covered with a 6-inch lift of a pea gravel mix. The mix shall be placed and spread uniformly. Wall concrete shall follow immediately and shall be placed upon the fresh pea gravel mix. If high range