Strength, thermal and environmental analysis of ultrahigh‑performance slag concrete: modelling and optimization approach.

AbstractThe replacement of waste glass powder (WGP) and electric arc furnace slag (EAFS) is a sustainable method for cost-effective and eco-friendly ultra-high-performance concrete (UHPC). This article evaluates the effects of using EAFS and WGP as weight replacements with fine aggregates and cement on the flow, setting time, compressive strength, thermal conductivity, and environmental performance. Nano-silica (NS) powder was used as a possible controller for the best rheological and hardened properties. Binary and ternary binder blends were assessed using the design of experiments (DoE) approach to investigate the technical feasibility of EAFS, WGP, and NS and their complementary role in improving concrete properties. Along with life cycle assessment (LCA), numerical optimisation was performed using second-order polynomial models accurately correlated between the investigated parameters and dependent responses to obtain an eco-friendly mixture having proper rheological properties and maximum compressive strength (>150 MPa). Results indicated replacing 11.6% WGP, 70% EAFS, and 0.6% NS in the UHPC mixture produced a 200-mm flow with enhanced strength (192 MPa). Maximum replacement of EAFS, 50%, and WGP, 30%, shows the best performance in energy, material, and climate footprints with a saving potential of up to 26%. In comparison, less saving is shown regarding water footprint with 9%. [ABSTRACT FROM AUTHOR]