低温和干湿循环双重环境下水泥砂浆抗硫酸盐侵蚀试验研究

结合我国西北地区实际情况，对低温、干湿循环双重环境下水泥砂浆抗硫酸盐侵蚀性能进行了试验研究。试验采用0.5和0.36两种水灰比，胶凝材料采用普通硅酸盐水泥、中抗硫酸盐硅酸盐水泥和在普通硅酸盐水泥中分别掺入15%矿粉+1%硅灰和15%矿粉+3%硅灰4种方案。结果表明：在低温、干湿循环双重环境作用下，化学侵蚀非常缓慢，砂浆的劣化主要是硫酸钠结晶导致的；降低水灰比能显著提高水泥砂浆抵抗硫酸盐侵蚀的性能；使用抗硫酸盐硅酸盐水泥能在一定程度上改善抗侵蚀性能；不同水灰比下，复掺矿粉和硅灰会表现出不同的效果，在低水灰比情况下能提高抗侵蚀性能，在高水灰比下反而会降低抗侵蚀性能。研究结果可为低温和干湿循环双重环境下的工程建设提供参考。

Sulfate Corrosion Resistance of Cement Mortar under Low Temperature and Dry Wet Cycles

In view of the actual situation in northwest China, we examined the sulfate corrosion resistance of cement mortar under the combined action of low temperature and dry wet cycles. We determined 0.50 and 0.36 as the water cement ratio of test cement mortar specimens; at each water cement ratio, we prepared four groups of mortar specimens with different binding materials: ordinary Portland cement, medium anti sulfate Portland cement, ordinary Portland cement dosed with 15% slag and 1% silica fume, and ordinary Portland cement dosed with 15% slag and 3% silica fume. The results are concluded as follows: under the combined action of low temperature and dry wet cycles, the degradation of cement mortar is mainly induced by the crystallization of sodium sulfate, with very slow chemical corrosion. Cutting the water cement ratio could remarkably improve the performance of cement mortar against sulfate attack. Anti sulfate Portland cement could enhance the corrosion resistance to a certain extent. Moreover, adding slag and silica fume would ameliorate the corrosion resistance of mortar with low water cement ratio, and vise versa. The results offer reference for constructions in the regions under combined action of low temperature and dry wet cycles.