Experimental Study On Anti-frozen Durability Of Concrete In Saline Soil Region

Durability is one of the most important indicators of high-performance concrete. There are plenty of research and report about the problem of durability of concrete all over the world, and it has been getting more new conclusions and new experience. Experts provide many effective measures to improve durability of concrete, but there are seldom research or conclusion about durability of concrete in salt lake. There are not only brine corrosion but also freeze-thaw circulation in the environment of salt lake in northwest of China. We should consider the influence of carbonation for concrete with much admixture. Therefore, the problem of durability of concrete in salt lake is very complex. It needs further research on the influence of carbonation, corrosion, freeze-thaw circulation, dry-wet circulation and the comprehensive effect to durability of concrete.The paper studies on frost-resistance of high performance concrete in Qinghai's Cha er han salt lake. Through smearing or mixing XYPEX material, the paper makes concrete specimens with XYPEX coating, the ones with mixing XYPEX and the ones without XYPEX in them. After this, the paper has done experiment about frost-resistance of the three group of concrete under the influence of freeze-thaw circulation, the comprehensive influence of freeze-thaw circulation + carbonation, freeze-thaw circulation + brine corrosion, and freeze-thaw circulation + carbonation + brine corrosion. It also discusses the principle and characteristics of the damage and failure process of these three types of concrete under single, double, comprehensive effect. Eventually, the paper finds that waterproofing material of XYPEX can improve frost-resistance of concrete in the environment of salt lake. According to the characteristics of freeze-thaw circulation, the paper builds mathematical model for freeze-thaw circulation of concrete and then calculate the parameters of concrete freeze-thaw damage equation by using least-square method. It also builds prediction model of freeze-thaw circulation life under natural environment, and it provides theoretical basis and basic parameters for freeze-thaw circulation life of concrete under natural environment, and it can achieve the purpose of anti-freezing design of concrete structure. The experiments in the paper have all done in labs, the paper suggests that we can increase exposure testing fields and launch long-term observations.