DESIGN AND DEVELOPMENT OF ADDITIVE FOR CO₂ FIXATION UTILIZING BY-PRODUCT CONTAINING Ca （3）─COMPOSITION DESIGN AND EVALUATION OF PROPERTIES OF γ-C₂S CLINKER UTILIZING RAW CONCRETE SLUDGE─

Abstract

Currently, in order to expand the use of additive for CO₂ fixation（main component：γ-C₂S）, there is a need to establish a composition design that utilizes by-product containing Ca other than by-product slaked lime as a CaO source. In this study, raw concrete sludge was used as by-product containing Ca, and the influence of CaO/SiO₂ molar ratio（C/S）on the production of γ-C₂S was evaluated. The results suggested that in a system using by-product containing Ca, the amount of γ-C₂S minerals can be maximized by setting the corrected C/S（C’/S’）to 2.0, taking into account the formation of C₄AF and C₂AS. In addition, it was confirmed that mortar specimens containing additive for CO₂ fixation admixture with adjusted C/S exhibited good strength development and CO₂-fixing ability.