A Comparative Study of Energy Consumption, Global Warming Potential and Impact Categories of Four Different Blends of Concrete Using Cradle to Gate Life Cycle Assessment

Abstract

The present study is a comparison of four different concrete mixes using ‘cradle to gate’ life cycle assessment. The aim is to obtain environmental impact, focusing mainly on criteria pollutants (CO, lead (Pb), PM10, NOx, SO_2, and volatile organic compounds), global warming potential, energy consumption, and impact categories like human health, ecosystem quality, and resources. Each concrete mix design has different binder combination. CONOPC contains ordinary Portland cement (OPC) as a binder. CONPPC has 27% Fly ash + 73% OPC while CON PSC has 47% ground granulated blast furnace slag (GGBS) + 53% OPC as a binder. CONGP has 100% fly ash as a binder without the use of cement. The comparative results show that all three concrete mixes, i.e., CONPPC, CONPSC, and CONGP, performed better than CONOPC in terms of harmful gas emissions, energy use, and GWP. Further, with respect to three impact categories, CONOPC has the highest score with 11.06 pt and CONGP has the lowest score with 1.68 pt. CONPPC shows a reduction by almost 30% with a value of 7.77 pt whilst CONPSC shows an even further reduction by 46% with a value of 5.95 pt compared to CONOPC. It is recommended that OPC cement should be replaced by either Portland slag cement (PSC) or Portland pozzolana cement (PPC) in concrete production. Geopolymer concrete is also a good substitute for traditional concrete. Recommendations from this work would assist concrete producers to choose the best available options without compromising the performance of concrete while reducing the negative environmental impact during production.