Study on mechanical strength and water resistance of organosilicon waterproofing agent blended recycled gypsum plaster

Abstract

In this study, organosilicon waterproofing agent blended recycled gypsum plasters (ROGPs) were prepared to determine their mechanical strength and water resistance. According to the results, the water to plaster ratio of ROGP increased steeply. Additionally, the mechanical strength and water resistance of ROGP decreased abruptly as the waterproofing agent increased, thus indicating the waterproofing agent’s loss of water resistance. Correspondingly, the water to plaster ratio and mechanical strength of organosilicon waterproofing agent blended commercial gypsum plasters (COGPs) slightly increased and decreased, respectively. Furthermore, the water resistance of COGP increased, and the suitable waterproofing agent was 1.0 %. The analysis shows that the large aspect ratio of ROGP and long-chain polymers increase their water to plaster ratios, whereas their mechanical strength and water resistance decrease owing to the resulting large plate-shaped crystals and poor overlapping between the crystals in hardened ROGP. The loss of water resistance is consequence of the oxidation of Si-H in ROGP. Therefore, different mechanical strength and water resistance development trends could be observed in ROGP and COGP. In principle, this study will contribute to the efficient utilization of recycled gypsum plaster.