Influence of NaCl concentrations on the crack-sealing behavior of superabsorbent polymers in cementitious materials

摘要

The crack-sealing behavior of superabsorbent polymers (SAPs) in high-concentration NaCl solutions is unclear. In this study, the influences of NaCl concentrations on the filled area (S) and sealing efficiency (r) of SAPs were, respectively, analyzed with a self-designed soaking test and a water permeability test. Furthermore, the 3D morphologies of a single SAPs particle and the effects of SAPs on the healing of mortars in NaCl solutions were investigated. The results indicate that the S value and the r value of SAPs are almost constant in low-concentration NaCl solutions, whereas they decrease with an increasing concentration until the concentration reaches the critical value. Additionally, the crack-sealing capacity of SAPs in realistic cracks is weaker than that in artificial cracks. Moreover, SAPs can promote the healing of mortar in wet-dry (0.5 M NaCl) cycles. The healing products are mainly CaCO3 and C-S-H gel. (C) 2020 Elsevier Ltd. All rights reserved.