Sustainability assessment of cement concrete modified with bagasse ash and calcite powder

Abstract

The continued global expansion in the built environment has resulted in significant demand for cement as a building and construction material. However, carbon dioxide emissions from the cement manufacturing processes contribute significantly to global warming and climate change. This study evaluates the sustainability of cement concrete mixed with bagasse ash (BA) and calcite powder (CP). A binary mixture of BA (5–15%) and CP (5–15%) was used in a partial replacement level of cement using a 25 MPa concrete mix design. Slump was examined while compressive strengths were tested after 7–28 days of water curing. Embodied energy, embodied carbon dioxide emissions, and sustainability index of the mixed concrete were evaluated after 28 days using the carbon and energy inventory. The results showed a decrease in slump as the replacement of bagasse ash and calcite powder in the mixture increased. In addition, the compressive strength of the mixed concrete decreased slightly as the percentage replacement of BA and CP in the mix increased. However, at 15% BA and 15% CP replacement level, the ternary concrete mix attained the compressive strength of 25.53 MPa compared to 29.45 MPa obtained for the control sample after 28 days. In addition, the blended concrete resulted in lower embodied energy, embodied carbon dioxide emissions, and sustainability index than the control concrete, meaning that cement-based concrete modified with BA and CP is more sustainable than Portland cement concrete.