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<br />03300 - 15/22 <br />G. Concrete with hardener shall be placed per the hardener manufacturers written <br />recommendations. <br />H. Casting New Concrete Against Old: Epoxy adhesive bonding agent shall be applied <br />to the old surfaces according to the manufacturer's written recommendations. This <br />provision shall not apply to joints where waterstop is provided, see SECTION 03100 <br />Concrete Formwork. <br />I. Temperature of Concrete: The temperature of concrete when it is being placed shall <br />be not more than 90 degrees F nor less than 55 degrees F for sections less than 12- <br />inches thick nor less than 50 degrees for all other sections. The CONTRACTOR <br />shall be entitled to no additional compensation on account of the temperature <br />requirements. <br />J. Hot Weather Placement <br />1. Placement of concrete in hot weather shall conform to ACI 305 and the <br />following: <br />2. When the temperature of the concrete is 85 degrees F or above, the time <br />between the introduction of the cement to the aggregates and discharge shall <br />not exceed [60] minutes. <br />3. If concrete is placed when the weather is such that the temperature of the <br />concrete would exceed 90 degrees F, the CONTRACTOR shall employ <br />effective means, such as pre-cooling of aggregates and mixing water using ice <br />or placing at night, as necessary to maintain the temperature of the concrete <br />below 90 degrees F as it is placed. <br />K. Cold Weather Placement <br />1. Placement of concrete in cold weather shall conform to ACI 306.1, and the <br />following: <br />2. Concrete ingredients shall not be heated to a temperature higher than that <br />necessary to keep the temperature of the mixed concrete, as placed, from <br />falling below the minimum temperature. <br />3. Remove all snow, ice, and frost from the surfaces, including reinforcement, <br />against which concrete is to be placed. Before beginning concrete placement, <br />thaw the subgrade to a minimum depth of 6-inches. Reinforcement and <br />embedded items shall be warmed to above 32 degrees F prior to concrete <br />placement. <br />4. Maintain the concrete temperature above 50 degrees F for at least 72 hours <br />after placement. <br />L. Order of Placing Concrete <br />1. The order of placing concrete in all parts of the WORK shall be acceptable to <br />the ENGINEER. In order to minimize the effects of shrinkage, the concrete <br />shall be placed in units as bounded by construction joints at the indicated <br />locations. The placing of units shall be done by placing alternate units in a <br />manner such that each unit placed shall have cured at least 5 days for <br />hydraulic structures and 2 days for all other structures before the contiguous <br />unit or units are placed, except that the corner sections of vertical walls shall <br />not be placed until the 2 adjacent wall panels have cured at least 10 days for <br />hydraulic structures and 4 days for all other structures.