Physical, Mechanical, and High-Temperature Performance of Cellulosic Fiber-Reinforced Foamed Concrete Containing Fly Ash and Pumice

Abstract

This study investigated the effects of fly ash (FA), pumice aggregate, and cellulosic fiber (CF) on the fresh, physical, mechanical, and high-temperature performance of cement-based foamed concrete, aiming to contribute to the production of sustainable building materials. In the mixtures, 22.5% of the cement was replaced with fly ash as the binder, and the water/binder ratio was kept constant at 0.40. Instead of pumice, cellulosic fiber was used at volumetric percentages of 0%, 0.5%, 1%, 2%, and 4%. The experimental study examined the spread diameter, fresh unit weight, apparent porosity, water absorption, and capillary water absorption properties, as well as the 7 and 28-day compressive and flexural strengths of the mixtures; furthermore, the strength and mass loss behavior after high temperature processing were evaluated. The results showed that increasing the CF ratio reduced the workability of the fresh mixture and decreased the fresh unit weight. Conversely, apparent porosity, water absorption, and capillary water absorption values increased, indicating a tendency towards a more porous internal structure. Mechanical tests have shown that increasing CF content decreases both compressive and flexural strength. In high-temperature tests, it was determined that as temperature and CF ratio increased, residual strength decreased, mass loss increased, and an inverse relationship was found between compressive strength and mass loss. In general, while the use of cellulosic fibers contributes to the lightness and sustainability potential of foamed concrete, it has negative effects on physical properties and mechanical performance, especially at high ratios. Therefore, it was concluded that the appropriate additive ratio for CF use should be determined by balancing sustainability and performance. Among the mixtures, 0.5% CF showed the most balanced overall performance and was therefore considered the most suitable CF ratio under the experimental conditions of this study.