Material efficiency in the design of UHPC paste from a life cycle point of view

In comparison to conventional concrete, ultra-high performance concrete (UHPC) is characterized by a significant improvement of mechanical properties and durability performance as a result of enhanced densification of the microstructure. The mixture design for enhanced material performance requires the use of higher quality material constituents and as a result, an increased cost, compared to conventional concrete. In this research, various UHPC pastes are designed and their material efficiency is evaluated. One such material efficiency parameter that is proposed here accounts for the influences of compressive strength, workability, unit cost and sustainability. The global warming potential (GWP) is selected to evaluate the environmental impact. Waste treatment, mass and economic allocation procedures of GWP for by-products are compared based on life cycle assessment (LCA) methodology. In order to better understand and quantify the contribution from each individual aspect on material efficiency, mechanical, economic and environmental indices are defined. As a result recommendations are made for efficient design of UHPC paste.