丁苯乳液-橡胶粉改性水泥基材料性能及其机理研究

Properties and Mechanism of Styrene-butadiene Rubber Latex-Rubber Powder Modified Cement-based Materials

以丁苯乳液(SBR)和废弃橡胶粉作为改性组分,研究它们对水泥基材料流变性、力学性能和微观结构的影响。结果表明:SBR能明显增大水泥净浆的流动度并使其表观黏度减小,改善硬化浆体的微观结构,提高硬化浆体的抗折强度和韧性;橡胶粉对硬化水泥浆体的抗压强度有不利影响,但能填充水泥石中的孔隙,提高其韧性;SBR-橡胶粉复合改性时,SBR在水泥颗粒表面成膜,限制熟料矿物的水化,使水化加速期的持续时间延长,水化产物生成量减少,但聚合物膜与水化产物及橡胶粉颗粒形成相互交织的空间网络结构,使浆体更加密实,显著提高水泥浆体的力学性能。

The styrene-butadiene rubber(SBR) latex and waste rubber powder were used as modified components to prepare polymer modified cement-based materials. The rheological property, mechanical property and microstructure of cement based materials were analyzed. The results show that SBR can increase the fluidity of the cement paste greatly, decrease its apparent viscosity, improve the microstructure of the hardened matrix and enhance its flexural strength and toughness. Although the waste rubber powder has an adverse effect on the compressive strength of hardened matrix, it can fill the pore in the cement matrix and enhance its toughness. When SBR-rubber powder composite modifies the cement mortar, SBR forms a film around the cement particles, limits the hydration of clinker minerals, prolongs the duration of the accelerated hydration period and reduces the amount of hydration products. However, the polymer film forms a spatial network structure with the hydration product and the rubber powder particles, which makes the matrix more compact and significantly improves the mechanical properties of the cement mortar.