消泡剂与减缩剂对聚合物改性水泥砂浆干燥收缩和质量损失的影响

Effect of defoamer and shrinkage reducing agent on drying shrinkage and mass loss of polymer modified cement mortar

研究了单掺消泡剂、单掺减缩剂及二者复掺对聚合物改性水泥砂浆的干燥收缩率和质量损失率的影响。结果表明,单掺消泡剂时,砂浆的干燥收缩率与质量损失率均会降低,且降低幅度与掺量成正比;单掺减缩剂时,砂浆的干燥收缩率降低且降幅与掺量成正比,质量损失率整体降低,但随着掺量的增加,减缩剂对质量损失的抑制作用逐渐降低;二者复掺对砂浆的干燥收缩与质量损失的抑制作用大于各自单掺时,具有明显的协同效应。砂浆的质量损失率与干燥收缩率之间存在幂函数关系,曲线参数受外加剂种类及掺量影响。

In the experiment,the influence of single defoamer,single shrinkage reducing agent and the compounds between them on the drying shrinkage and mass loss rate of polymer modified cement mortar were discussed.The results show that the drying shrinkage rate and mass loss rate of mortar will be reduced when defoamer is added alone,and the reduction effect is proportional to the dosage.When the shrinkage reducing agent is added alone,the drying shrinkage rate of the mortar will also be reduced and the reduction effect is proportional to the dosage.Although the mass loss rate decreases as a whole when the shrinkage reducing agent is added alone,the inhibitory effect of shrinkage reducing agent on mass loss gradually decreases with the increase of dosage.The inhibitory effect of the two on the drying shrinkage and mass loss of mortar is greater than that of single mixing.There is obvious synergistic effect between them.Through research,it is found that there is a power function relationship between the mass loss rate of mortar and the drying shrinkage rate,which is affected by the type and dosage of admixture.