粉煤灰砼的干燥收缩性能

Study on the Dry Shringkage of Concretes with Fly Ash

研究了粉煤灰对砼干燥收缩性能的影响。试验结果表明 :(1)在同水胶比条件下掺入粉煤灰 ,砼干缩值有些增加 ,但增幅不大。 (2 )在同标号 (R2 8)条件下 ,粉煤灰掺量不大时 (2 5 % ) ,砼的早期 (7d)干缩值平均增幅约为 13 % ,后期 (180d)平均增幅约 12 .6% ;大掺量粉煤灰砼 (4 0 % )早期 (7d)增幅较大 ,平均高达 2 6% ,后期 (180d)增幅较小约为 15 .7% )。 (3 )在同水胶比同掺量下 。

In this paper, the influence of fly ash on the dry shringkage of concretes was studied. The results show that::(1) Under the condition of the same water-binder ratio, the dry shringkage of concrete with fly ash has a little increasing compared to the reference concrete, but the effect of increasing is not obvious. (2)Under the condition of the same strength (R28).When the addition of fly ash is 25%, the averages of dry shringkages of concrete at 7 day and 180 day are about 13%and 12.6%respectively, When the addition of fly ash is 40%, the averages of dry shringkages of concrete at 7 day and 180day are about 26% and 15.7% respectively.(3) Under the condition of the samewater-binder ratio and the same ddition. There is no obvious difference between the dry shringkage of concretes with fly ash and the dry shringkage of concretes with ground slag.