盐碱溶液对混凝土抗冻性能的影响

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，采用正交方案试验研究了SA溶液及水灰比、含气量和粉煤灰掺量3个参数对混凝土抗冻性能的影响．结果表明，由于产生渗透压和结晶压，盐碱溶液对混凝土的抗冻性能有严重的影响．水灰比为0．40的混凝土，置于SA溶液中的最大冻融次数比相应的置于水中的最大冻融次数平均减少22．5％；含气量对混凝土抗冻性能的影响最大，水灰比次之，粉煤灰掺量最小；随着含气量增加，最大冻融次数增大，当含气量从3．0％增大至6．0％时，最大冻融次数的增加幅度较小；随着水灰比和粉煤灰掺量的增大，最大冻融次数减小；孔结构是影响混凝土抗冻性能的最根本因素，优化孔结构是改善混凝土抗冻性能的核心技术措施．

Influence of Saline-Alkaline Solution on Freezing Resistance of Concrete

Based on the compounding characteristic of concrete in cold saline-alkaline area, imitating to compound SA solution as the test condition, orthogonal experiment was applied to study the influence of water-cement ratio, entrained air content and content of fly ash on the freezeing resistance of concrete. The results show that causing osmotic pressure and crystalline pressure, the saline-alkaline solution takes a great of influence on freezeing resistance of concrete, for example, the maximum number of freezeing-thaw cycle of concrete dipped in SA solution decreases 22.5% averagely when water-cement ratio is 0.4; the influence order of these three factors on freezeing resistance is entrained air content, water-cement ratio, content of fly ash; with entrained air content increasing, the freezeing resistance of concrete increases; with water-cement ratio and content of fly ash increasing, the freezeing resistance of concrete decreases; pore structure is the critical factor of affecting freezeing resistance of concrete, so improving pore structure is the key technology for improving the freezeing resistance of concrete.