Mechanical performance of lightweight fiber reinforced geopolymer mortar incorporating expanded clay at elevated temperatures

This study examines the impact of using lightweight expanded clay aggregate (LECA) and polyvinyle alcohol (PVA) fibers on the properties of lightweight geopolymer mortar. The effect of temperature level (room temperature, 250°C, and 500°C) on the mechanical properties of LWGM with and without fibers is also explored. LECA is used as a partial replacement to river sand with 60% and 80%. The base material utilized for LWGM is slag which was activated by a mixture of sodium silicate and sodium hydroxide solutions. Three different mixtures were prepared and cured at ambient temperature. The fresh properties in terms of workability and density were performed. A series of experiments, such as compression, flexural and uniaxial tensile tests were carried out to assess the mechanical properties of LWGM with and without fibers. The study found that increasing the level of LECA replacement leads to a decrease in the density and compressive strength of the LWGM. Furthermore, incorporating a 1% PVA fiber volume fraction improved the flexural, and tensile behavior of LWGM significantly. The experimental results indicated that the mechanical properties of tested samples subjected to the elevated temperatures of 500°C changed noticeably. Keywords: Lightweight Geopolymer Mortar (LWGM), Lightweight Expanded Clay Aggregate (LECA), PVA Fibers; Elevated Temperatures, Mechanical Properties.