外加剂对混凝土气密性能的影响研究

Study on the effect of admixtures on the airtightness of concrete

系统研究了减水剂、引气剂、消泡剂对混凝土工作性能、强度、透气系数等的影响规律。结果表明:掺入减水剂有利于提高混凝土试件的气密性,其中磺酸盐减水剂对混凝土试件气密性的改善效果最佳;掺入引气剂能够有效提高混凝土的气密性,但随着其掺量增加,混凝土试件的透气系数先减小后增大,其中掺0.2%引气剂混凝土试件的透气系数最小,为1.4×10-12 cm/s;随着消泡剂掺量增加,混凝土拌合物的扩展度减小,凝结时间差缩短,抗压强度比先增大后减小,混凝土硬化体透气系数先减小后增大,其中有机硅消泡剂对混凝土气密性的改善作用较明显。

This article systematically studies the influence of water reducing agents,air entraining agents,and defoamers on the performance,strength,and permeability of concrete.The results show that adding water reducing agents is beneficial for improving the airtightness of concrete specimens,among which sulfonate water reducing agents have the best effect on improving the airtightness of concrete specimens.Adding air entraining agent can effectively improve the air tightness of concrete,but as the dosage continues to increase,the air permeability coefficient of concrete specimens decreases first and then increases.Among them,the air permeability coefficient of concrete specimens with 0.2%air entraining agent is the lowest,at 1.4×10-12 cm/s;As the amount of defoamer increases,the expansion of the concrete mixture decreases,the setting time difference shortens,the compressive strength ratio first increases and then decreases,and the permeability coefficient of the hardened concrete body first decreases and then increases.Among them,organic silicon defoamers have a more obvious improvement effect on the airtigthtness of concrete.