Influence of Sustainable Concrete Mix Designs on Costs and Global Warming Potential

Abstract

Pressure continues to increase globally within governments and various industries such as manufacturing and construction to embrace eco-friendly practices aiming to diminish CO2 emissions; therefore, researchers worldwide started developing innovative eco-friendly materials such as concrete with supplementary cementitious materials (SCM); low cement concrete (LCC) using advanced mix design techniques such as PPM’s and/or MP’s; and recycled concrete aggregates (RCA), etc. These materials are at different stages of research for their use in structural application and have proven to have the same and/or superior performance to conventional concrete throughout the research completed in the past few years, but the concrete industry currently has a lack of knowledge on cost for the use of these materials which represents a current gap in the literature that needs further research. Since the construction industry’s main constraint nowadays on all projects is the cost associated with the work, and since the use of innovative eco-friendly materials in infrastructure construction is becoming a requirement, the cost associated with these materials needs to be studied further. This study aims to evaluate the upfront cost impact and global warming potential of different sustainable concrete mixtures such as use of SCM’s, PPM’s, MP’s, and RCA’s in concrete mixtures. The direct cost of each of these concrete mixtures may vary due to a variety of factors such as market conditions, material availability, region, and supply/demand; therefore, the purpose of this study is to review the relative difference of these mixtures under same conditions. Trends in the construction industry show that due to resource constraints and new sustainability requirements, conventional concrete mixtures will become obsolete and will need to be replaced by innovative eco-friendly mixtures. Results of this study indicate that the use of PPM’s, MP’s and RCA’s either individually or in combination are not just able to reduce the cost of concrete mixtures but also reduce the global warming potential (GWP). Two new parameters were established as part of this work, first was to simultaneously assess cost and eco-efficiency using a “carbon cost intensity” (CCI) factor; second was to simultaneously assess concrete’s performance, economic impact, and environmental impact using a “Integrated Strength Cost Eco-Efficiency” (I-SCEE) coefficient.