掺合料及引气剂对混凝土抗盐冻剥蚀性能的影响

针对盐类及冻融循环耦合作用环境,选择混凝土单面盐冻试验方式,研究矿物掺合料及引气剂对混凝土抗冻剥蚀性能的改善作用。结果表明:与基准混凝土相比,在混凝土中掺加活性矿物掺合料和引气剂能够减小混凝土的剥蚀量和相对动弹性模量损失率,提高混凝土的抗盐冻剥蚀性能;掺加磨细矿渣的混凝土抗盐冻剥蚀性能优于粉煤灰混凝土,与其他配合比混凝土相比,复掺粉煤灰、硅灰和引气剂的混凝土,抗盐冻剥蚀性能最好。因此,在盐类存在的冻融环境应提倡矿物掺合料复掺技术。单面盐冻后,混凝土的表面剥蚀量都较大,但混凝土的相对动弹性模量损失率相对较小,因此在单面盐冻过程中混凝土的破坏形式以表面剥蚀为主。

EFFECT OF ADMIXTURE AND AIR-ENTRAINING AGENT ON SALF-FROST SCALING RESISTANCE OF CONCRETE

Depending on the environment coupling of salts and freeze-thaw cycles,the test method of single-side salt-frost was selected and improvement of mineral admixture and air-entraining agent on salt-frost scaling resistance of concrete was researched.The results show that the scaled mass and the dynamic modulus of elasticity loss rate of the concret are reduced as compared with control concrete by adding mineral admixture and air entraining agent into concrete.The salt-frost scaling resistance of concrete is improved.The salt-frost scaling resistance of concrete mixed with ground slag is better than flyash concrete.Compared with the concrete of other proportion the salt-frost resistance of concrete with fly ash,silica fume and air-entraining agent is better.So the mineral admixture coupled technology is promoted in this more complex situation of salt and freeze-thaw cycles.After single-side salt-frost the scaled mass of the concret is more but the dynamic modulus of elasticity loss rate is less,so the damage of concrete mainly depends on the surface scaling.