混凝土硫酸盐侵蚀速度影响因素研究

研究了水灰比、胶砂比、试件尺寸、预养方式、溶液浓度及温度对混凝土硫酸盐侵蚀速度的影响.结果表明:试件的水灰比越大、胶砂比越小、试件尺寸越小(比表面积越大),则硫酸盐侵蚀速度越快;提高养护温度、缩短养护时间可以加快硫酸盐侵蚀速度;硫酸盐侵蚀速度随着硫酸盐溶液浓度增大和温度提高而加快,但当浓度和温度超过某一数值后,硫酸盐侵蚀速度反而减慢.在各种条件下,混凝土硫酸钠侵蚀速度比混凝土硫酸镁侵蚀快;对硫酸钠型侵蚀,采用抗折抗蚀系数作为判定指标较为合理,而对硫酸镁型侵蚀,应该综合考虑抗折、抗压抗蚀系数.

Investigations of Influence Factor on the Rate of Concrete Sulfate Attack

The effects of water cement ratio,cement sand ratio,specimen size,pre-storage method,solution concentration and temperature on the rate of concrete sulfate attack were investigated.The test results show that the speed of attack is accelerated with the increasing of water cement ratio,the decreasing of cement sand ratio and the smaller size of the specimen.The specimen with large water cement ratio,small cement sand ratio and small size should be adopted in order to accelerate the test speed of sulfate attack.High prestorage temperature and short pre-storage time can accelerate the speed of sulfate attack.When solution concentration and temperature are lower than certain value,the speed of attack is accelerated with increasing concentration and temperature.However,higher temperature and concentration of solution may decrease the rate of attack.The speed of attack of sodium sulfate is faster than that of magnesium sulfate under various conditions.It is suitable to adopt the coefficient of tensile strength as the accelerated assessing criterion for the attack of sodium sulfate.For the attack of magnesium sulfate,the coefficient of tensile and compressive strength should be considered together.