环氧树脂乳液的成膜特性及对超高性能混凝土的改性作用

Abstract

掺加不同聚灰比和不同固脂比(固化剂与环氧树脂乳液的质量比，下同)的聚合物对超高性能混凝土(UHPC)进行改性，测定改性水泥浆体的水化放热速率和放热量，用SEM观察改性UHPC的微观组织结构，并用压汞法(MIP)分析改性的孔结构。结果表明，聚合物在水化的0~6 h会加快水泥浆体的水化放热速率，在水化的加速期6~15 h和15 h以后则起减速作用；当固脂比为0.5时，环氧树脂乳液固化后形成相互交错缠绕的纤维状薄膜；随着聚灰比的增加，改性UHPC的平均孔径增大，孔隙率先减小后增大，抗折强度和压折比不断减小，粘接强度升高，当掺量达到15%时，改性UHPC的粘接强度达到2.75 MPa。 The ultra-high performance concrete (UHPC) was modified by adding different latex contents cement ratios and different S/E ratios (the mass ratio of solidification agent and epoxy resin emulsion, the same below) of polymer; the hydration rate of the modified UHPC was researched; the microstructure of the modified UHPC was observed by SEM and the pore structure of the modified UHPC was analyzed through mercury injection method (MIP). The results show that the polymer accelerates the hydration speed of the modified cement paste in 0 - 6 h, and plays a role of inhibition in 6 - 15 h and after 15 h. When the S/E ratio was 0.5, the epoxy resin emulsion exists as overlapping fibers after being solidified. The average pore diameter of modified UHPC increases with the increase of polymer content, while the porosity increases before decreasing; the flexural strength and the ratio of compressive to flexural strength decrease, and adhesive strength increases. When the content of polymer is 15%, the adhesive strength reaches 2.75 MPa.