Water permeability and rapid self-healing of sustainable sulfur composites using superabsorbent polymer and binary cement

This study investigated the rapid self-sealing of modified sulfur polymer composites incorporating super-absorbent polymer (SAP) and binary cement. The SAP was employed as a primary remedy for the rapid self-sealing in less than 30 min. The binary cement was used as a secondary self-healing element, and was composed of calcium sulfoaluminate (CSA) expansive agent and Portland cement. The mixture cases were prepared and tested varying the proportions of the components of binary cement, depending on the presence of SAP. Water permeability tests were conducted on through-crack samples to evaluate their rapid self-sealing performances under water penetration. Nondestructive tests including elastic wave transmission and optical microscopy were carried out to assess the effectiveness of SAP and binary cement on the rapid self-healing. The test results revealed that the presence of SAP dramatically accelerated the rapid self-sealing performance. The SAP particles quickly swelled up by absorbing water, and sealed and bridged between the two crack faces, which likely assisted the nucleation and growth of hydrated products around them. In addition, an increasing ratio of CSA expansive agent in the binary cement led to the better rapid self-sealing. (C) 2020 Elsevier Ltd. All rights reserved.