高延性水泥基复合材料抗渗性能及微观结构研究

Study on impermeability and microstructure of engineered cementitious composite

本文围绕高延性水泥基复合材料的抗渗性能开展研究,对正交试验得到的最优组进行能量演化分析,采用电镜扫描(SEM)技术分析最优组的微观结构,利用X射线衍射(XRD)分析各试验组的水化产物。试验结果表明:硅灰掺量对提高ECC的抗渗性能有显著影响,ECC的能量在峰值应力点后发生快速耗散,基体发生破坏,最优组中钙矾石(AFt)和水化硅酸钙(C-S-H)搭接形成了稳定的空间结构,同时膨胀剂进一步促进AFt的生成,有助于填补空隙。

In this paper,the impermeability of high ductility cement-based composites was studied.The energy evolution of the optimum group obtained by orthogonal test was analyzed,and the microstructure of the optimum group was analyzed by SEM while the hydration products were analyzed by X-ray diffraction(XRD).The experimental results show that the content of silica fume has a significant effect on improving the impermeability of ECC.The energy of ECC dissipates rapidly after the peak stress point,which leads to the destruction of the matrix.In the optimal group,the stable spatial structure was formed by the overlap of ettringite(AFt)and calcium silicate hydrate(C-S-H).At the same time,due to the effect of expansion agent,AFt was further generated,which helps to fill the gap.