EVALUATION OF MECHANICAL AND DURABILITY PROPERTIES OF CONCRETE WITH INCREASED LEVELS OF SUPPLEMENTARY CEMENTITIOUS MATERIALS

Abstract

This study investigates the mechanical properties and durability of concrete incorporating increased levels of supplementary cementitious materials (SCMs) as a strategy to reduce the carbon footprint of the construction industry. While the Korean Industrial Standard (KS L 5201) currently limits the addition of SCMs to 10% for Portland cements, this research evaluates the feasibility of expanding replacement levels up to 15%. The binders tested include various ternary blends of limestone powder (LSP), blast furnace slag (BFS), and fly ash (FA). Experimental results indicate that concrete with increased SCM content exhibits lower compressive strength at early ages (3 and 7 days) compared to Ordinary Portland Cement (OPC) concrete. However, by 91 days, the compressive strength of the SCM-blended mixes reached levels equivalent to OPC, attributed to the latent hydraulic reaction of BFS and the pozzolanic reaction of FA, which refine the binder matrix. Notably, the mix with 15% SCM (LSP 5% + BFS 10%) demonstrated the most stable strength development and adequate resistance to chloride penetration, meeting practical performance criteria. The study concludes that increasing SCM content up to 15% is a viable approach for achieving carbon neutrality without compromising long-term structural performance.