Using Supplementary Cementitious Materials for Sustainable Concrete

Abstract

The need for infrastructure expansion and the need to preserve the environment, driven by the use of concrete as a building material, are growing daily. Concrete is the second-most-consumed material after water. It is necessary to use alternative, sustainable materials, particularly recycled ones. The construction industry must urgently utilise SCMs (Supplementary Cementitious Materials) or industrial waste as alternatives to cement in concrete manufacturing, as this exacerbates environmental problems and increases cement costs. The development of sustainable, high-performance concrete involves the use of silica fume (SF), metakaolin (MK), and fly ash (FA). The mixture with SF (5–10%), MK (5–15%), and FA (10–30%) maintains workability through optimised water-to-binder ratios and admixtures. Durability assessments, including chloride penetration, sulfate resistance, and water absorption, as well as compressive, flexural, and split tensile strengths at multiple curing ages, are evaluated in this analysis. This research demonstrates how to produce low-carbon, durable, and sustainable concrete suitable for next-generation construction applications. Silica fume (5–10%), metakaolin (5–15%), and fly ash (10–30%) are integrated as partial replacements for cement in a single optimised mix design for a ternary SCM concrete system. The complementary reactivity and particle-packing characteristics of the three SCMs are used simultaneously in this proposed mix to improve the targets' strength, durability, and sustainability. The chloride penetration, sulfate resistance and water absorption for compressive, flexural and split tensile strengths were evaluated at multiple curing ages. The compressive strength and up to 40% reduction in chloride permeability, sulfate-induced expansion compared with the control mix, and the optimised ternary blend achieved about 16% higher 28-day strength, demonstrating low-carbon, durable, and sustainable concrete.