掺合料和纤维对泡沫轻质混凝土干缩性能的影响

摘要

The foamed lightweight concrete sample was prepared by adopting physical foaming technology and the ordinary portland cement was used as a cementitious material, the drying shrinkage tests were carried out to investigate the inhibition effect of the admixtures as glass fiber, fly ash and silicon fume on drying shrinkage of concrete sample.The results show that the drying shrinkage value of foamed lightweight concrete with different wet densities increases with curing time increasing,which grows fast in early period and tends to be stable in later period. The drying shrinkage value of the foamed lightweight concrete gradually decreases with the increase of the wet density.The glass fiber could significantly inhibit the drying shrinkage of foamed lightweight concrete,the drying shrinkage of foamed lightweight concrete could be decreased in a certain extent by an appropriate amount of fly ash or silicon fume,but excessive amount of admixture has a negative impact on drying shrinkage.%以普通硅酸盐水泥为胶凝材料,采用物理发泡技术制备泡沫轻质混凝土试样进行干缩试验,探讨玻璃纤维、粉煤灰、硅粉等外加剂对其干缩的抑制效果.结果表明:不同湿密度泡沫轻质混凝土的干缩值均随着龄期的增长而增大,早期干缩值增长较快,后期趋于稳定;随湿密度的增大,泡沫轻质混凝土的干缩值逐渐减小;玻璃纤维能显著抑制泡沫轻质混凝土的干缩;在合适掺量范围内,粉煤灰或硅粉能在一定程度上减小泡沫轻质混凝土的干缩,但掺量过大会对干缩产生不利影响.