Analysis of Drying Shrinkage Performance of Ultra-Fine Sand Concrete

以不同掺量的特细砂取代机制砂制备特细砂混凝土试件，分析不同水胶比下特细砂掺量与粉煤灰掺量对试件干燥收缩性能的影响。结果表明，特细砂混凝土干燥收缩率随着养护龄期的增加呈现先增加后趋于平稳的变化趋势，在45 d龄期时达到最大干缩率。特细砂混凝土干燥收缩率随特细砂替代率增加而增加，特细砂替代率为20%时，特细砂混凝土干燥收缩性能最好。掺量28%粉煤灰抑制混凝土干燥收缩效果优于掺量18%粉煤灰。水胶比0.34、粉煤灰替代率28%及特细砂替代率20%时，特细砂混凝土干燥收缩性能最好。Ultra-fine sand concrete specimens were prepared by replacing machine-made sand with different dosages of ultra-fine sand. The effects of the dosages of ultra-fine sand and fly ash on the drying shrinkage performance of the specimens were analyzed under different water cement ratios. The results showed that the drying shrinkage rate of ultra-fine sand concrete showed a trend of first increasing and then stabilizing with the increase of curing age, reaching the maximum drying shrinkage rate at 45 days of age. The drying shrinkage rate of ultra-fine sand concrete increases with the increase of ultra-fine sand replacement rate. When the ultra-fine sand replacement rate is 20%, the drying shrinkage performance of ultra-fine sand concrete is the best. The inhibitory effect of 28% fly ash on concrete drying shrinkage is better than that of 18% fly ash. When the water cement ratio is 0.34, the substitution rate of fly ash is 28%, and the substitution rate of ultra-fine sand is 20%, the drying shrinkage performance of ultra-fine sand concrete is the best.