盐碱溶液对混凝土氯离子渗透性能的影响

基于盐碱寒冷地区的工程环境与混凝土的配制特点,模拟配制了SA溶液,对水灰比、含气量和粉煤灰掺量三个参数对混凝土氯离子渗透性能的影响进行了正交试验研究.结果表明:氯离子渗透深度x与渗透时间t之间的关系可以拟合成幂函数x=atb来描述,且在显著性水平α=0.01下其相关关系显著;SA溶液中SO42-和Mg2+的存在对于Cl-的渗透具有一定的抑制作用,冻融循环在混凝土本体结构未破坏之前对于氯离子的渗透也具有一定的抑制作用;水灰比、含气量和粉煤灰掺量三个参数对浸于4.0%NaCl溶液、SA溶液、SA溶液并受冻融循环三种情况下氯离子渗透深度影响的顺序不同;随着水灰比的增大,氯离子渗透深度增大;粉煤灰能够抑制氯离子的渗透,且20%掺量的效果优于35%;含气量对于抵抗氯离子渗透存在不利影响,且未受冻融作用时,3.0%的影响更大.

Influence of saline-alkaline solution on chloride permeability of concrete

Based on environmental features and compounding characteristics of concrete in cold saline-alkaline (SA) zone,by using compounded SA solution,an orthogonal experiment was carried out to study the influence of water-cement ratio,entrained air content and content of fly ash on the chloride ion permeability of concrete. Results show that:the relationship between chloride ion penetration depth x and its penetration time t can be described as x=atb,and the relativity is significant when the significance level a is 0.01; the existence of SO42-and Mg2+ions in SA solution restrains the penetration of Cl-ion to some extend,and so does the freezing and thawing cycle before the concrete is destroyed; the sequence of three parameters which influence the chloride ion penetration depth is different when the concrete is immerged in 4.0% NaCl solution,SA solution and SA solution with freezing and thawing cycle; the chloride ion penetration depth grows with the increasing water-cement ratio; the restraint of chloride ion penetration by fly ash is better at the blend ratio of 20% than 35%; the air content ratio is unfavorable to restrain the chloride ion penetration,especially at the ratio of 3.0% without freezing and thawing cycle.