High volume fly ash concretes for sustainable applications in construction

Abstract

Reducing CO2 emission has become one of the most important subjects that the world focuses. Various actions are taken to make the construction materials and methods sustainable since the construction industry has a great contribution to the world's CO2 emissions. Replacement of cement with alternative binders is considered the most efficient and practical way to increase the sustainability of concrete. Fly ash usage in concrete has several effects for increasing sustainability. It decreases the use of cement and environmental pollution while it enhances some properties of concrete. Increased level of replacement further decreases environmental damage made by the production of concrete if targeted performance parameters could be obtained. In this study, the fresh properties, strength properties, and durability properties of different concrete mixtures were examined. The structural design of an industrial floor was made by using these ordinary concrete (PCC) and high- volume fly ash concrete (HVFAC), and the materials were compared by means of required thickness, environmental impact, and economic impact. Two replacement levels (40-60%) and two water/binder ratios (W/B) (0.35-0.50) were considered, and the mechanical properties of the mixtures were determined. Based on TR34, thickness design for an industrial floor was done for all concrete series. Environmental and economic impact analysis was done for all concrete series. Compared to PCC mixtures, lower mechanical properties, higher thickness requirements, and lower environmental impact values were found for HVFAC mixtures. With decreasing W/B, enhanced performance parameters were obtained for both PCC and HVFAC mixtures. The results of this study show that the environmental impact of concrete could be further decreased by increasing the replacement level of fly ash and still targeted performance parameters could be obtained from industrial floors.