Innovative use of agro-waste cane bagasse ash and waste glass as cement replacement for green concrete. Cost analysis and carbon dioxide emissions

Abstract

The individual incorporation of cane bagasse ash (CBA) and waste glass (WG) as substitutes of cement changes the properties of concrete. The aim of this study was to investigate the effects of using CBA with WG as cement substitutes on concrete properties. Different mixtures with cane bagasse ash and waste glass were prepared. The workability of concrete mixtures was evaluated by slump test immediately after casting, density and compressive strength were tested at 28 days. Additionally, cost analysis, carbon dioxide emissions and alkali-silica reaction were evaluated. Using cane bagasse ash with waste glass to produce concrete achieved better results for physical and mechanical properties than the concrete mixture using CBA or WG individually as a partial substitute for cement. The experimental results show that the incorporation of cane bagasse ash decreased the slump related with the low water absorption of CBA. Additionally, the hardened density of concrete incorporating waste glass and cane bagasse ash was lower than traditional concrete, however a definite trend was not observed. The combined use of CBA and WG has a positive contribution in achieving the highest compressive strength. The results exhibited that the incorporation of cane bagasse improved the compressive strength. The CBA15:WG5 mixture can increase 20% compressive strength in comparison with CBA0:WG20 mixture (without CBA). Additionally, CBA15:WG5 mixture have 8% lower cost than the traditional concrete CBA0:WG0. With the partial substitution of 20% of cement by ashes from cane bagasse ash and waste glass, it is possible to reduce the emission of CO2 for each m3 of material produced. On the other hand, the introduction of cane bagasse ash reduces the alkali silica reaction effect.