| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacture of concrete wherein entrapped air is allowed to disappear in a process for manufacture of concrete, and a target air amount is constituted by entrained air to be generated from an air entraining agent to raise a ratio of the entrained air. SOLUTION: Primary cast cement of an amount 70% to 85% of the cement amount calculated according to a specified formula based on initial design conditions is employed. Primarily kneaded ready-mixed concrete is obtained by kneading the primary cast cement together with water, a fine aggregate, a coarse aggregate, an air entraining agent and an air entraining and water reducing agent for a kneading time 2 to 4 times a specified kneading time. Then, after adding the residual amount of cement to the primarily kneaded rady-mixed concrete, the concrete is manufactured by secondarily kneading for a specific kneading time.
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