The Impact of Transportation and Emissions Allocation on the Global Warming Potential of Concretes Containing Alternative Binders and Fillers

A wide variety of waste products including municipal and industrial wastes have been used in concrete production with this assumption that their utilization in concrete either as binders or fillers can contribute to the sustainability in construction. However, such assumptions may not be true without conducting explicit environmental assessments of concrete and alternative products. This is important because when quantifying their environmental impacts in the context of life-cycle assessment (LCA), depending on the assumptions made, it is possible that wastes and by-products can have higher emissions than the materials that they are intended to replace. To investigate the impact of modelling assumptions, this chapter aims to conduct a detailed LCA for concrete mix designs when considering the utilisation of waste and by-products either as binders or fillers. When considering alternative binders with different allocation methods and transportation modes, the critical transportation distances at which 843 geopolymer concretes (GPC) can be more emissions intensive than their equivalent traditional concretes are identified. In a similar context and through a comparison of emissions factors associated with the preparation of natural and alternative aggregates, the critical transportation distances are also found at which from the context of carbon emissions it is better to utilise naturally available resources or waste products as aggregates. The results reported in this chapter can help understand the impact of different modelling assumptions and to identify the optimum type of concrete in terms of alternative binders and fillers to benefit circular material use in civil engineering.