Life Cycle Assessment and Environmental Efficiency of Concrete Materials

Many materials have been proposed as 'green' alternatives to conventional concrete constituents. A life cycle assessment (LCA) approach is adopted to model the processes included in the life cycle of concrete. Five LCA software packages are evaluated to select a tool for use in this work. The sensitivity of LCA results to the composition of Ontario's electricity grid is analyzed. Allocation of environmental impact to by-product materials, namely fly ash, is investigated. Six functional units representing various levels of complexity and incorporating strength and durability performance are developed. Finally, a methodology for calculating Environmental Efficiency Indicators (EEIs) for concrete is presented. EEIs are calculated for eight mix designs containing varying amounts of alternative concrete materials. The results show that supplementary cementitious materials and limestone cement improve EEI. The EEI of photocatalytic cement concrete is improved if SCMs are incorporated. Recycled aggregate concrete has a lower EEI compared to conventional concrete.