Study on mechanical and durability properties of fiber-reinforced self-compacting geopolymer concrete

In order to solve the problem of shrinkage cracking and poor toughness of self-compacting geopolymer concrete (SCGC), this study explored the regulation of PP fiber and glass fiber with different lengths of 6mm, 9mm, and content of 0%, 0.3%, and 0.6% on its performance, combined with fiber reinforcement theory to analyze the mechanism. The results show that PP fiber has a stronger inhibition on fluidity, and the self-compacting property is lost when the content is more than 0.3%, and the influence of glass fiber can be ignored. In terms of mechanical properties, 0.6% content of 9mm PP fiber has the best toughening effect, and the splitting tensile strength at 28 days is 97.25% higher than that of M0, and the high content of glass fiber deteriorates the performance. In terms of durability, PP fiber has better impermeability. The water seepage height of MP6-0.3 group is 40.96% lower than that of M0, but the fiber reduces the high temperature resistance. Excessive PP fiber significantly weakens the residual strength after 600 °C, and the strength loss rate of MP6-0.6 group reaches 73.85%. The conclusion shows that 0.3% -0.6% of 9mm PP fiber is recommended in non-high temperature environment, glass fiber is preferred for fluidity, and PP fiber is avoided at high temperature, which provides reference for engineering application.