Effects Of Marine Micro And Macroalgae Building Blocks On Strength Development In Green Cement Composites

Abstract

The utilization of biomass-based green cement has gained significant attention in the concrete industry as sustainability becomes a key focus. Among the available biobased additions, marine algal materials have emerged as a promising candidate due to their advantageous features such as rapid growth rate and efficient carbon sequestration. However, incorporating algae into the cement matrix presents challenges, involving hindrance and retardation of the hydration reactions, leading to a decline in the mechanical properties of algae green cement. In this study, we aimed to investigate the chemical interactions between two types of algae fillers, namely spirulina and ulva, and the cement matrix. Initially, we examined the interaction in a simplified chemical system using biopolymer representatives (glucomannan, lactalbumin, sucrose, and stearic acid). The results demonstrated a significant decrease in the mechanical properties of glucomannan and alpha-lactalbumin cement composites. Consequently, we conducted a study involving extraction-modified algae-cement composites to investigate further the interaction between the algae fillers and the cement matrix. We found that both hot and cold water-extracted spirulina and ulva resulted in an improvement in compressive strength. Furthermore, the formation of distinct nanofibers in 500-700 nm within the matrix was observed in the case of lactalbumin-cement composites and hot water-extracted spirulina supernatant cement composites, suggesting that proteins may act as the main hindering agents in the hydration reaction and facilitate protein-related inorganic byproducts. Overall, this study enhances our understanding of the algae-induced hindrance mechanisms on the cement hydration reactions and provides a starting point for improving algae-cements through non-chemical pretreatment on algae biomatter.