硫酸盐环境混凝土动弹性模量及微观研究

针对西部重盐渍土地区混凝土的耐久性问题,以内掺复合掺合料制成的高性能细石混凝土和普通硅酸盐水泥以及抗硫酸盐水泥制成的高性能细石混凝土作为研究对象,在硫酸钠溶液中进行干湿循环后,通过对动弹性模量的测量以及对混凝土SEM形貌分析,结果表明,在干湿交替的恶劣环境中,抗硫酸盐水泥混凝土的抗侵蚀性能并不比普通水泥混凝土好;掺加复合掺和料的高性能细石混凝土对硫酸盐侵蚀有较好的抵抗性能;掺加矿物掺合料能够与混凝土内部的不利成分Ca(OH)2发生二次水化反应,生成有利的C-S-H凝胶,有效改善混凝土的微观结构;并给出了在盐渍土地区拌制混凝土的建议.

Dynamic elastic modulus and microstructure study of concrete in sulfate environment

Aimed at the durability of concrete in serious salt regions,a study was carried out to examine the performance of various high-performance minute stone concretes in the sulfate environment,such as the high-performance minute stone concrete with inside composite additive,the portland cement concrete and the resist-sulfur cement concrete.The variety of elastic modulus was examined and the SEM of concretes was analyzed after the dry-wet cycle in sodium solution.Test results show that the bittern resistance of resist-sulfur cement concrete is not better than that of portland cement concrete in the execrable dry-wet cycle environment;and the high-performance minute stone concrete with inside composite additive has better repellence to the sulfate environment.A Secondary hydratation of the composite additive with the disadvantage component Ca(OH)2 in the concreteoccurs,and the advantaged C-S-H gel is produced,which can reform the microstructure of concrete effectively.Moreover,the advice to mix concretes in salt region is put forward.