Mechanical behavior of fiber reinforced slag-based lightweight geopolymer mortar incorporating artificial lightweight aggregate exposed to elevated temperatures

Scholars all over the world are becoming increasingly interested in the production of lightweight building materials through the utilization of wastes and by-products. The present research focused on the production of fiber-reinforced lightweight geopolymer mortar, cured with ambient temperature. For this purpose, artificial lightweight aggregate (ALWA) was used as a partial replacement of river sand to minimize the density of the geopolymer mortar. The effect of PVA fibers on the properties of the lightweight geopolymer mortar was also studied before and after exposure to elevated temperatures. The fresh and mechanical properties were evaluated through experimental tests including workability, density, and, compressive, flexural, and tensile tests. Based on the test results, the incorporation of ALWA reduced the density of the geopolymer mortar, mainly because of the small unit weight of ALWA. The results also show that the addition of PVA fibers resulted in a reduction in density, workability, and compressive strength, while it leads to an improvement in the flexural and tensile properties of the lightweight geopolymer mortar. Moreover, the results indicated that adding PVA fibers improves the fire resistance and eliminates the risk of spalling in mortar specimens during the heating processes. Keywords: Lightweight Geopolymer Mortar, Artificial Aggregate, PVA Fibers, Mechanical Properties, Elevated Temperatures.