使用橡胶轮胎颗粒改性砂浆性能研究

Use of Type Rubber Particles in Lag-modifiedcement Mortars

利用矿渣改性硅酸盐水泥和卡车轮胎(主要是是SBR橡胶、粒径小于300μm、通过10%(按重量计)经NaOH处理的橡胶颗粒制备砂浆标准试件,采用毛细吸附法、浸水法、耐酸蚀法,通过对断裂面的扫描电镜和弯曲强度试验分析研究,发现随着橡胶粉的增加弯曲强度降低(橡胶试样为3.6±0.5 MPa,对照试样为6.5±0.8 MPa)。另一方面,增加橡胶粉的有利影响是改善了它的运输性,Sorptivity系数每分钟降低0.29~0.06 mm。通过浸泡,有橡胶粉的标准试件吸水率降低16%。橡胶标准试件通过抗酸性试验重量有显著的下降,扫描电镜照片显示,试样中存在微裂纹,橡胶试样中存在闭合气孔。这个结果显示小颗粒橡胶粉能改善砂浆的性能即使含有高含量的橡胶粉。

Mortar specimens were prepared using slag-modified Portland cement and 10%(by weight of mortar)of NaOH-treated rubber particles,smaller than 300μm,from truck tyres(mainly SBR rubber).Water sorption by capillarity and by immersion,resistance to acid attack,surface of fracture analysis by scanning electron microscopy and flexural strength experiments were performed.Flexural strength was reduced with the addition of the rubber(3.6±0.5 MPa for the specimens with rubber,6.5±0.8 MPa for the control).On the other hand,advantageous effects of the addition of the rubber were observed on the transport properties of mortar.Sorptivity coefficient was reduced from 0.29(control)to 0.06 mm/min1/2.By immersion,the amount of water absorbed by the specimens with rubber was reduced in 16%.A significant decrease in the rate of weight loss by acid attack was observed for specimens with rubber.SEM micrographs showed the presence of microcracks in the specimens and closed pores in the specimens with rubber.These results show that small rubber particles can improve some mortar properties even when used in a high proportion.