改性纳米CaCO_(3)对水泥基复合材料性能的影响

Influence of Modified Nano-CaCO_(3) on the Properties of Cement-based Composites

采用乙烯醋酸乙烯酯可再分散乳胶粉(EVA)对纳米CaCO_(3)颗粒进行改性,并用吸光光度法分析其分散效果。掺入浓度为5%~20%的EVA溶液和1.0%~2.5%的纳米CaCO_(3)制备了水泥基复合材料试件(NCC),研究了改性纳米CaCO_(3)对NCC抗压强度的影响,并用SEM对NCC微观结构进行了表征。结果表明:EVA溶液对纳米CaCO_(3)具有良好的分散作用;纳米CaCO_(3)掺量相同时,EVA溶液浓度越大,减水剂掺量越少;当EVA水溶液的浓度为15%,纳米CaCO_(3)掺量为胶凝材料质量的2.0%时,NCC各龄期的抗压强度最高,表面孔隙较少。

The nano-CaCO_(3) powder was modified by ethylene-vinyl acetate redispersible latex powder(EVA),and its dispersion effect was analyzed by absorptiometry.The cement-based composite specimens(NCC)were prepared by adding EVA aqueous solution with a concentration of 5%~20%and 1.0%~2.5%nano-CaCO_(3),and the effect of modified nano-CaCO_(3) on the compressive strength of NCC was studied,and the microstructure of NCC was characterized by SEM.The results show that the EVA aqueous solution has a good dispersing effect on the nano-CaCO_(3).When the content of nano-CaCO_(3) is the same,the greater the concentration of EVA solution,the less the content of water reducing agent.When the concentration of EVA aqueous solution is 15%,and the content of nano-CaCO_(3) is 2.0%of the mass of the cementitious material,the compressive strength of NCC is higher than that of the control group,and the surface pores are less.