PREPARATION OF AGGREGATE FOR DAM CONCRETE

摘要

PROBLEM TO BE SOLVED: To facilitate the sieving of fine aggregate and coarse aggregate by classifying riverbed gravel in an unwashed state to the gravel of specific grain sizes, passing the gravel through the inside of a water tank to sufficiently wet the surfaces with water and to allow the mud components sticking to the surfaces to settle on the water bottom to separate the mud components, thereby managing the surface water rate of the riverbed gravel to a stable value. SOLUTION: Riverbed gravels are classified by a 80-mm sieve and a 10-mm sieve to two; a grain size <=10 mm and a grain size 10 to 80 mm. The as-collected riverbed gravel is sent by a belt conveyor to a 80-mm sieving machine, the passed riverbed gravels are further sent by a belt conveyor to a 10-mm sieving machine to classify to the coarse aggregate of the grain size 10 to 80 mm and the fine aggregate of the grain size <=10 mm. The coarse aggregate and the fine coarse aggregate are respectively placed on the belt conveyors and are passed through the inside of the water tank. The coarse aggregate and fine aggregate past the inside of the water tank are sent to the respective metering device of a concrete kneading machine. The mud components deposited on the bottom of the water tank are occasionally taken out and are dried. The proper amount thereof is incorporated in a powder form into the dam concrete and is thus used.