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为了对加速养护引起的普通混凝土抗氯盐渗透能力负效应进行改善,制作了4种掺矿物掺和料混凝土试件.在达到一定的初始强度后,试件被分别放入40,60和80℃水槽中进行加速养护.在28,100,200和300 d龄期,根据ASTM C1202试验标准测定了试件的电通量,同时还对部分试件进行了快速氯离子扩散系数和压汞实验.实验结果表明,加速养护会导致普通混凝土的抗氯盐渗透能力线性劣化,而通过掺加矿物掺合料能够改善混凝土的微观孔隙结构和负效应.对掺矿物掺合料混凝土而言,60℃是获得较优抗氯盐渗透能力的加速养护温度上限.20℃常温条件的预养护对减轻此负效应有利,同时随着测试龄期的增长混凝土中胶凝材料的不断水化负效应也得以减轻.
In order to improve the negative effect of ordinary concrete on chlorine penetration resistance caused by accelerated curing, four types of concrete admixtures with mineral admixtures were fabricated. After a certain initial strength was reached, the specimens were put into 40, 60 and 80 ℃ for 28, 100, 200 and 300 d.The electric fluxes of samples were measured according to the ASTM C1202 test standard, and fast chloride diffusion coefficient and mercury intrusion were also tested on some samples.The results show that , Accelerating the maintenance would lead to the linear deterioration of ordinary concrete resistance to chloride penetration, and by adding mineral admixture can improve the microscopic pore structure and the negative effect of concrete.For mineral admixture concrete, 60 ℃ is to obtain more The optimal upper temperature limit for anti-chloride penetration is the pre-curing of 20 ℃ ambient temperature, which is beneficial to reduce this negative effect. Meanwhile, the continuous hydration negative effect of cementitious material in concrete decreases with the increase of test age.