WANG Wenshuai1, ZHANG Peng1, WEI Xiaoxue2, WU Jingjiang2, ZHANG Chengshi2
Abstract:
To prepare high-performance epoxy resin cementitious repair materials (ECRM) for effectively addressing dam crack rehabilitation, the influence of the content of epoxy resin, nano-SiO2, and steel-PVA hybrid fiber on the bonding properties of cementitious repair materials was analyzed by the interface flexural bonding strength test. The strengthening mechanism of the bonding properties of cementitious repair materials was revealed by the scanning electron microscope test. The results showed that the interface flexural bonding strength of cementitious repair materials increased first, and then decreased with the increase of epoxy resin, steel fiber, and PVA fiber content. When the content of epoxy resin was 9% (mass fraction, the same below), the volume content of PVA fiber was 0.9% (volume fraction, the same below), and the volume content of steel fiber was 1.2%, the interface flexural bonding strength of cementitious repair materials reached the maximum, which was an increase of 68.2% compared to the control group (without epoxy resin, nano-SiO2, PVA fibers, and steel fibers). As the content of nano-SiO2 increased from 0% to 2.0%, the interface flexural bonding strength of cementitious repair materials gradually rosed with an increase of 14.7%. Compared to nano-SiO2, steel fiber, or PVA fiber, the addition of epoxy resin had a more significant effect on the improvement of the bonding properties of cementitious repair materials. The microscopic strengthening mechanism of cementitious repair materials could be concluded as follows, the addition of epoxy resin and steel-PVA hybrid fiber could inhibit the formation and expansion of cracks in the matrix and improve the integrity of the matrix. The addition of nano-SiO2 could reduce the hole defects in the matrix and improve the compactness of the matrix.