Mixture proportioning approach for low-CO2 concrete using supplementary cementitious materials

Abstract

This study developed a simple and rational mixture proportioning procedure for low-CO2 concrete using supplementary cementitious materials (SCMs) such as fly ash (FA), ground-granulated blast-furnace slag (GGBS), and condensed silica fumes (SF). Life-cycle CO2 reduction ratio was critically considered as one of the targeted requirements. The effect of SCMs on CO2 reduction and the compressive strength of concrete was examined by a nonlinear multiple regression analysis using a total of 12,537 datasets, which produced schematized data allowing for the straightforward design of SCMs for satisfying the targeted requirements. Considering the determined substitution level of SCMs for a targeted CO2 reduction ratio, unit binder content and water-binder ratio (W/B) were formulated for the designed compressive strength and entrained air content of concrete. The fine aggregate-to-total aggregate ratio (S/a) was determined from the quadratic formula of a parametrized value for a targeted initial slump of concrete. Overall, the developed procedure is expected to encourage the practical production and application of low-CO2 concrete in the ready mixed concrete field.