The Effect of Fire Flame Exposure on Some Properties of Structural Lightweight Self-Compacting Sustainable Concrete

This study investigates the mechanical, physical, and microstructural performance of structural lightweight self-compacting concrete (SLWSCC) using waste glass as a partial substitute for natural sand and micro-steel fibers as reinforcement under high-temperature conditions. The research will focus on optimizing the sustainability, fire resistance, and structural performance of lightweight concrete and reducing the effects of waste disposal. Four mixes were made, a control mix (REF) and three mixes, which included 20%, 30%, and 40 %of waste glass, which weighed 30%of sand, reinforced by 1 %of micro-steel fibers. Slump flow, V-funnel, and L-box tests were used to determine fresh properties based on EFNARC guidelines to verify self-compacting behavior. Measurement of hardened properties, before and after exposure to 200°C, 400°C, 600°C, and 800°C, was done to assess compressive strength, splitting tensile strength, density, and water absorption. The specimens were heated in a gas furnace, followed by foam cooling. Scanning Electron Microscopy (SEM) analysis of the microstructure revealed information on the integrity of the matrix and the development of pores and fiber-matrix bonding at high temperatures. The resultant of waste glass enhanced the strength and density of values dramatically in ambient conditions because of the micro-filling effect. The G30+MS mix was the most effective one, with a higher compressive strength of 9.2% (52.2 MPa) than the control mix; it retained 35% of its strength at 800°C, which was higher than that of the reference mix. Micro-steel fibers limited the propagation of cracks and avoided spalling, retaining the structural integrity of the composite after exposure to fire.