Integrated mechanical, durability and sustainability assessment of eco-efficient concrete using SCM, RCA and additive synergy

Abstract

ABSTRACT The increasing demand for sustainable construction has encouraged the development of low-carbon, high- performance concrete using industrial by-products and wastes. This study experimentally investigates the individual and combined effects of supplementary cementitious materials (SCMs), recycled concrete aggregates (RCA), and mineral admixture Icrete on the mechanical, durability, microstructural, and sustainability performance of concrete. Class F fly ash (10–50%), ground granulated blast furnace slag (10–50%), and silica fume (2.5–12.5%) were used as partial cement replacements, while RCA (10–50%) replaced natural coarse aggregates. Icrete was added at 0.5–2 wt.% of the cementitious material. Results identified optimal SCM contents of 20% fly ash, 40% GGBFS, and 7.5% silica fume, with silica fume delivering the best. Compressive strength increased by 17.4% and 13.2% at 28 and 90 days, respectively, compared to conventional concrete. Although RCA reduced strength and increased permeability, these effects were mitigated by combining SCMs with Icrete. The optimal mix (7.5% silica fume, 20% RCA, and 2% Icrete) achieved compressive strengths of 46.0 MPa and 51.5 MPa at 28 and 90 days, along with a 30% reduction in water absorption. This research optimizes three-phase SCM blends with RCA, Icrete, and a six-parameter sustainability assessment, enabling mechanistic and quantitative performance recovery in eco-efficient structural concrete.