Work

Comparative performance of fly ash and Portland cement in alkali-activated bagasse ash-based cellular lightweight concrete for sustainable non-load-bearing masonry units

Year: 2026

Type: article

Abstract: The development of low-carbon cellular lightweight concrete (CLC) using industrial by-products has attracted increasing attention as a sustainable alternative to conventional Portland cement (PC)-based materials. This study compared the effects of high-calcium fly ash (FA) and PC on the performance of alkali-activated bagasse ash (BA)-based CLC. BA was partially replaced with FA, PC, or their combinations and activated using 10 M or 15 M sodium hydroxide (SH), while maintaining a target fresh density of 1000 kg/m 3 . Compressive strength, water absorption, drying shrinkage, thermal conductivity, and microstructure were evaluated. Test results revealed that increasing SH concentration generally improved compressive strength and reduced water absorption. Mixtures containing both FA and PC showed the best overall performance. The optimum mixtures satisfied the strength requirements for non-load-bearing cellular concrete and exhibited thermal conductivity values ranging from 0.307 to 0.458 W/m-K. Compared with the PC-based CLC reference, the optimized alkali-activated CLC mixtures achieved comparable engineering performance with lower PC consumption through the utilization of BA and FA. Beyond comparing FA and PC, this study reveals the relationships among calcium source, engineering performance, thermal insulation, and embodied CO 2 emissions. These findings provide practical guidance for designing low-carbon alkali-activated CLC for non-load-bearing masonry applications.

Source: Next Materials

DOI: 10.1016/j.nxmate.2026.103361