粉煤灰对引气混凝土的抗冻性及气孔结构的影响

摘要

混凝土的抗冻性受诸多因素影响,而掺入粉煤灰后的混凝土对混凝土的抗冻影响很大.为了更好的了解粉煤灰对引气混凝土抗冻性能的影响,对比研究了普通硅酸盐引气混凝土与掺入30％粉煤灰的普通硅酸盐混凝土在不同水灰(胶)比的抗冻性能及气泡参数.试验研究表明:普通及掺粉煤灰引气混凝土质量损失率都随水灰(胶)比的增大而升高,而动弹性模量及相对动弹性模量都随水灰(胶)比的增大而减小.掺粉煤灰的普通硅酸盐引气混凝土的初始动弹性模量明显小于普通硅酸盐引气混凝土.相比较普通引气混凝土,掺入粉煤灰后小孔径气泡数量增加,大孔径气泡数量同样也增加了.在同水胶比下,掺粉煤灰的引气混凝土的气泡间距系数明显要小于不掺粉煤灰的普通引气混凝土,掺入粉煤灰会减小引气混凝土的比表面积,掺入粉煤灰后引气混凝土的气泡平均半径明显增大.%The antifreeze of concrete is influenced by many factors,and the concrete's antifreeze is very influential when mixed with fly ash.In order to better understand the influence of fly ash on properties of air-entraining concrete frost resistance,comparative study the Portland airentraining concrete with 30％ fly ash added Portland concrete under different water cement (gum) than the antifreeze performance and bubble parameters.Experimental study show that the ordinary and mixing fly ash air-entraining concrete quality loss rate are along with the increase of the ratio of water-cement (glue),and the dynamic modulus of elasticity and relative dynamic elastic modulus with the increase of the ratio of watercement (glue).The initial dynamic elastic modulus of the ordinary silicate induced concrete with fly ash is significantly lower than that of ordinary silicate induced concrete.Compared with ordinary air-induced concrete,the number of small aperture bubbles increased with the addition of fly ash,and the number of large aperture bubbles also increased.Under the same water/cement ratio,mixing fly ash of the bubble spacing coefficient of air-entraining concrete obviously less than ordinary air-entraining concrete mixing fly ash,specific surface area of the mixed with fly ash can decrease the air-entraining concrete,air-entraining concrete mixed with fly ash after the average bubble radius increased obviously.