Autogenous healing of hollow natural fiber (HNF)-reinforced reactive magnesium cement (RMC)

Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China

Abstract

This work investigated the autogenous healing of interface bond between hollow natural fiber (HNF) (e.g., sisal fiber) and reactive magnesium cement (RMC). Preloading -reloading test was conducted to single fiber embedded specimens, the results suggested that the interface bond can be improved by over 300% after wetting-air cycles conditioning, and hot water conditioning demonstrated greater healing efficiency compared to room temperature conditioning. Based on SEM-EDS characterization, this prominent restoration of interface bond is due to: 1) further hydration and carbonation of RMC, which partially fills the microcracks between fiber and matrix; 2) the migration and precipitation of expansive agents in lumens, which improves the contact between sisal fiber and matrix. Furthermore, the interface bond healing resulted in a significant recovery of the fiber-bridging strength of sisal fiber-reinforced RMC, the fiber-bridging strength doubled after healing compared with that of preloading.