不同取代方式下粉煤灰对砂浆抗压强度的影响

Effect of Fly Ash on Mortar Compressive Strength under Different Substitution Ways

研究了龄期为7d、28d、60d、120d,粉煤灰取代水泥、取代细集料和混合取代三种取代方式下砂浆抗压强度的发展状况,建立了预测砂浆抗压强度增长因子双参数模型。结果表明:龄期与取代率对强度增长因子的影响是相互独立的;抗压强度增长因子随龄期的增长而增大;取代水泥时,抗压强度增长因子随取代率的增大而减小;取代细集料时,抗压强度增长因子随取代率的增大先增大后减小,最大值点在20%左右;取代细集料对抗压强度的增长较取代水泥有利;混合取代得到的增长因子介于取代水泥和取代细集料得到的二者之间。

The development of compressive strength of mortar is studied under 3 substitution ways of substituting fly ash for cement and thin aggregate and mix substitution on the basis of 4 ages（7d, 28d, 60d, 120d）. Writers establish double parameter model predicting compressive strength growth factor of mortar. Results indicate that the effects on compressive strength growth factor caused by ages and substitution rate are respective; compressive strength growth factor increases with the increasing of ages; when substituting fly ash for cement, compressive strength growth factor reduces with the increasing of substitution rate; when substituting fly ash for thin aggregate, compressive strength growth factor increases firstly and then reduces with the increasing of substitution rate, when substitution rate is about 20%, strength growth factor is maximum; substituting fly ash for thin aggregate is more advantageous than substituting fly ash for cement to the increasing of compressivestrength of mortar; strength growth factor of mix substitution is between that of substituting fly ash for cement and that of substituting fly ash for thin aggregate.