High-temperature response of geopolymer concrete: influence of silica fume content and fiber type on mechanical and structural integrity

Geopolymer concrete has recently attracted increasing attention as an alternative to traditional concrete due to its low carbon emissions and environmental friendliness.In addition, geopolymer concrete has great potential due to the use of industrial waste materials in its mixture and its high performance.The aim of this study is to experimentally investigate the effects of adding 0%, 10% and 20% silica fume instead of granulated blast furnace slag in the geopolymer mixture and 1% basalt fiber and polymer fiber addition on the performance of geopolymer concrete under high temperatures.In the study, both dry unit weight and water absorption rate for the evaluation of physical properties and compressive and flexural strength properties for the evaluation of mechanical performance were investigated in detail.212 cube and 108 prism samples with dimensions of 50x50x50 mm and 40x40x160 mm were produced, respectively.Samples were exposed to temperatures of 20C, 100C, 200C, and 400C, and compressive strength, flexural strength, mass loss, and load-deflection curves were analyzed.The results obtained showed that although the temperature increased up to 100C, causing the strength to increase by 25%, the strength of the samples decreased by 70% at a temperature of 400C.In addition, it was observed that the strength of the samples decreased with the increase of the SF ratio in the mixtures, but the use of polymer fibers balanced the mentioned negative effect.These findings show that durable and sustainable building materials can be produced under high temperature conditions when the SF and fiber type are optimized together.The study contributes to the material design for applications requiring high temperature resistance.