| 摘要 |
PROBLEM TO BE SOLVED: To perform an appropriate concrete quality control by setting a slump as specified when unwashed riverbed pebbles are used as aggregates. SOLUTION: When a solid content obtained by dry-blending unwashed riverbed pebbles measuring 80 mm or less as aggregates with a specified amount of cement is to be charged into a stirring container aboard an agitator truck together with water and an intimate mixing agent and the mixture is to be kneaded into a concrete, an initial charge of water is set to be less than originally estimated quantity and then the amount of water corresponding to the slump, of the concrete contained in the stirring container, which is estimated based on the hydraulic pressure of a hydraulic motor for rotating the stirring container of the agitator truck or water and the intimate mixing agent are additionally charged. In this way, the slump of the concrete contained in the stirring container is slightly increased to obtain a specified slump.
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