A Comparative Study of Life Cycle Assessment for Sustainable Concrete Mixes

Developing countries need infrastructure for development thereby increasing the demand for concrete. The production of raw materials, manufacturing of concrete, and transportation process emit a large amount of greenhouse gases and particulate matters in the atmosphere which has increased energy consumption as well as global warming potential (GWP), acidification potential (AP), and eutrophication potential (EP) impact. In the present study, a comparative Life Cycle Assessment (LCA) is performed on five types of concrete mix and two fuels like coal and agricultural waste. The controlled mixed concrete CM-O was prepared by 100% OPC and the other four types of agricultural waste concrete were prepared by partial replacement of cement with agricultural waste ash in one cubic meter concrete. Optimum replacement level of cement was obtained based on 28 days compressive strength of concrete. LCA was evaluated by using CML methodologies on Microsoft excel for Cradle - to - gate boundary system. Similarly, environmental load due to the burning of coal and agricultural waste was evaluated. The results indicated that agricultural waste concrete has the potential to decrease the environmental load of the manufacturing of concrete. The environmental load is 1701.985 kwh, 501.051kg, 4.327kg and 466.091g for energy consumption, GWP, AP, and EP respectively for one cubic meter of controlled mix concrete. The results indicated that Rice husk ash at a replacement level of 12.5% of cement has 4.3%, 10%, 7.1%, and 3.7% lesser environmental impact for energy, GWP, AP, and EP respectively when compared with controlled mixed concrete. Further, the use of agricultural waste as fuel emits very less amounts of greenhouse gases mainly CO2, SO2, and NOx, and has an overall less impact on environmental compared to coal. This study would encourage the industrialists to make decisions about the use of agricultural waste as supplementary cementitious materials (SCMs) and fuel.