Unsaturated Polyester Resin Filled with Cementitious Materials: A Comprehensive Study of Filler Loading Impact on Mechanical Properties, Microstructure, and Water Absorption

[Image: see text] In recent years, cheaply available cementitious materials (CMs) are increasingly finding useful applications in construction engineering. This manuscript focused on the development and fabrication of unsaturated polyester resin (UPR)/cementitious material composites to be potentially useful in a variety of construction applications. For this purpose, five types of powders from widely available fillers, i.e., black cement (BC), white cement (WC), plaster of Paris (POP), sand (S), and pit sand (PS), were used. Cement polymer composite (CPC) specimens were prepared by a conventional casting process with various filler contents of 10, 20, 30, and 40 wt %. Neat UPR and CPCs were investigated mechanically by testing their tensile, flexural, compressive, and impact properties. Electron microscopy analysis was used to analyze the relation between the microstructure and mechanical properties of CPCs. The assessment of water absorption was conducted. The highest tensile, flexural, compressive upper yield, and impact strength values were recorded for POP/UPR-10, WC/UPR-10, WC/UPR-40, and POP/UPR-20, respectively. The highest percentages of water absorption were found to be 6.202 and 5.07% for UPR/BC-10 and UPR/BC-20, while the lowest percentages were found to be 1.76 and 1.84% for UPR/S-10 and UPR/S-20, respectively. Based on the finding of this study, the properties of CPCs were found to depend on not only the filler content but also the distribution, particle size, and combination between the filler and the polymer.