Super absorbent polymers (SAP) in building materials: Application opportunities through physico-chemical and mechanical analysis

This paper shows the physicochemical and mechanical characterization of a new plaster material lightened with superabsorbent polymers (SAP) and reinforced with fibers. First, an experimental campaign has been conducted to determine the ideal quantity of sodium polyacrylate polymer (NaPA) to be added, analysing three water/plaster ratios and three different amounts of SAP. The aim is to achieve the maximum reduction in density and optimal mechanical resistance. Once this analysis was conducted, a 0.7 water/plaster ratio and 0.015 SAP/gypsum ratio were determined as the ideal mixture. With this, a complete characterization of the new material was conducted, also considering the incorporation of three different fibers. SAP addition led to a significant apparent density reduction in the new plaster compounds produced, reaching values up to 27 % lower than the reference samples. From those samples with fibers, kevlar and glass fiber got a better mechanical performance, always exceeding the limit values established by current regulations. In the same way, the incorporation of these superabsorbent polymers has managed to reduce the original plaster material thermal conductivity by up to 32 %, as porosity increased. Thus, it has been confirmed that the incorporation of superabsorbent polymers in the production of plaster compounds is a viable alternative to produce lightweight prefabricated elements within wide field of application for the design of new prefabricated elements.