Microstructural and thermal characterization of polyethylene fiber-reinforced geopolymer composites

The use of geopolymer (GPL) as a non-combustible mineral matrix for fiber -reinforced composites and environmentally acceptable building materials is growing. When fibers are added to GPL, its brittle behavior changes to ductile or quasi -ductile, producing fiber -reinforced GPL composites that function well. The novelty in the present research involves analyzing the effects of high temperature and polyethylene (PE) fiber content on mechanical and microstructural properties to determine how PE fiber reinforcement influences the thermal performance of GPL composites. In this study, the main objective is to assess various GPL mixes to investigate how the inclusion of PE fiber and exposure temperature affect the material 's performance after being subjected to elevated temperatures. These included compression tests, flexural tests, scanning electron microscopy, bubble parameter testing, thermogravimetric and differential thermal analysis, and mass loss measurement. The PE fiber concentrations varied between 0 % and 1.5 % by volume of the mix, and the exposure temperatures were established at 25, 200, 400, 600, and 800 degrees C. A twoway ANOVA analysis was performed to examine the significance of variation in the results due to the addition of PE fibers and elevated temperatures. According to the results, the GPL mortar observed a significant mass loss as the temperature rose from 25 degrees C to 250 degrees C. But from 250 degrees C to 710 degrees C, there was very little mass loss, and from 710 degrees C to 800 degrees C, there was no more loss. The GPL mortar thickened as the temperature increased, but more pores and cracks appeared. At 25 degrees C, adding PE fibers to GPL improved compressive strength by 16.2 % -35.55 % for 0.25 % - 1.50 % dosages. Over 1.0 % led to a significant reduction because of uneven distribution, compromising homogeneity, and increasing porosity. The melted fiber defects had a minor effect on the strength of the mortar, even if the PE fiber broke down at higher temperatures. With an ideal fiber content of 1.50 % below 200 degrees C, PE fibers greatly enhanced the flexural properties of GPL mortar, resulting in a 6.30 % -58.00 % increase in flexural strength. Conclusively, incorporating PE fibers improves the flexural strength of GPL up to 200 degrees C, but beyond this temperature, there is a significant decline of the flexural strength, showing the fibers' effectiveness up to a specific temperature.