关键词: 湿接缝混凝土;纤维增强;微膨胀;微结构

Abstract: The effects of steel fiber, MgO-type expansive agent ( MEA) and their composite on the performance of wet joint concrete were studied.The interface structure between steel fiber and matrix in concrete was observed by stereoscopic microscope, and the pore structure of mortar in concrete was measured by mercury pressure method.The results show that the incorporation of MEA is favorable for compensating the shrinkage of concrete.With the increase of steel fiber content, the expansion rate of expansive concrete is decreasing.Steel fiber and MEA composite can effectively improve the volume deformation of concrete.The synergistic effect of steel fiber and MEA improves the micro-structure of concrete, increases the density of matrix and between steel fiber and matrix, and enhances the bonding force of the matrix to steel fiber, which is more conducive to improving the mechanical and permeability of wet joint concrete.

Key words: wet joint concrete;fiber reinforcement;micro-expansion;microstructure