Sustainable limestone and EAF aggregate concretes through particle packing models (PPMs) and life cycle assessment (LCA)

Abstract

In view of the current concern about environmental problems, the use of slags from the Electric Arc Furnace (EAF) as aggregates in the concrete has been proved to be successful for multiple applications avoiding the use of natural aggregates. Hence, the range of aggregates available for designing concretes is continuously growing.The main objective of this thesis is to design economic and environmentally sustainable concrete mixes made with natural limestone (NL) aggregates and electric arc furnace (EAF) aggregate through a particle packing density perspective without compromising their compressive strength and workability.In order to verify the potential of particle packing theories to design more economical and environmentally sustainable NL aggregate and EAF aggregate concrete mixes, two traditional optimal curves and two current discrete packing models were validated with experimental packing results to demonstrate its feasibility in the prediction of the most compacted structure. Several (17) NL and EAF aggregate concrete mixes were then designed by varying the aggregate proportion and the content of cement paste to analyse the effect of aggregate packing density on the fresh and hardened concrete properties. Finally, the economic and environmental impact of the different concrete mixes were assessed to evaluate the potential of the particle packing methods in the development of more sustainable concrete.It was concluded that the concrete mixtures designed by maximizing the coarse aggregates content in the range of the maximum packing density present the highest compressive strength and workability and the low environmental and economic impact. In addition, due to the higher compressive strength and the low contribution of aggregate in the concrete environmental impact, the EAF aggregate concrete contributes to a greater reduction of the environmental and economic impact.