Use of Belt Conveyors to Transport Mass Concrete.

摘要

A series of tests was conducted to determine the effects of using conveyor belts to transport concrete. Concrete mixtures containing aggregate up to 6in. in nominal maximum size were mixed,placed on conveyors arranged in a triangular pattern,transported up to simulated distances of 6000ft,and tested for changes in temperature,air content,and workability (slump). The results indicate: (a) no change in temperature of the concrete results due to conveying,per se; (b) less than 0.5percent loss of air may be expected from concrete containing approximately 5percent air; (c) slump loss of approximately 1-1/2in. may be expected when conveying for 1500ft or less within 10-15min; (d) comparative tests of idle concrete showed a 1-1/2-in. slump loss at 20-25min; (e) indications are that slump loss is increased with (1) increased belt travel time and (2) for a given travel time,greater belt speed;and (f) when conveyor belts are kept full,no segregation due to conveying is apparent.