Production of cleaner binders by reusing agricultural by-products: An approach towards zero cement concrete for sustainable future infrastructure

Abstract

Alkali-activated binders are considered a low carbon alternative for cement. However, it is important to address the carbon dioxide emission and high cost associated with the currently used commercial activators. Hence, recent studies focus on developing sustainable, low-cost alternative activators. Although rice husk ash derived activator is a potential alternative to commercial activators, studies on rice husk ash derived activator is highly limited. Hence, the present study focuses on the performance evaluation of alkali-activated binders using rice husk ash derived activators. The effect of activators is studied for bagasse based binary and ternary alkali-activated binders. Moreover, the influence of rice husk ash derived activators is meticulously compared with commercial sodium silicate derived activators. In addition, the influence of heat and ambient curing was also investigated. Mechanical, durability and microstructural properties of bagasse ash based alkali-activated binders were assessed. Bagasse ash-fly ash based binders activated using rice husk derived activators yielded the maximum compressive strength. However, bagasse ash-slag based binders with commercial sodium silicate activators exhibited higher performance than rice husk ash derived activators. In the case of bagasse ash-slag-fly ash based ternary binders, specimens activated using the rice husk ash derived activator had better performance than specimens activated using the other conventional activators. Even though the addition of 10% bagasse ash increased the performance of fly ash based binders, the incorporation of bagasse ash reduced the performance of slag and ternary alkali-activated binders. The results also showed that the rice husk ash based activator is a feasible alternative for the activation of bagasse based precursors to generate desirable mechanical strengths and durability.