Synergic effect of sustainable quaternary binder on quantitative and qualitative aspects of high strength mortar

Abstract The main goal of this present experimental investigation is to explore the performance characteristics of a high-strength quaternary binder-based matrix consisting of calcined sea shell powder (CSSP), class F fly ash (FFA), ground-granulated blast furnace slag (GGBS), and ordinary Portland cement (OPC). The sustainable binder, created by incorporating 50% OPC, 20% FFA, and, remaining 30% with varying combinations of GGBS and CSSP, were investigated experimentally using six distinct mixes which were further compared with control OPC mix. Sophisticated microstructural assessment methods were employed to characterize the binder materials. Fresh properties of the quaternary binder paste and mortar were determined using consistency tests, setting time, slump test, and Puntke test. After 28 days of curing, the reaction degree of all binder mixes were ascertained. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) were among the tests performed on hardened pastes, which revealed the presence of C-S-H gel. Water absorption, ultrasonic pulse velocity, and compressive strength tests were conducted on the hardened quaternary binder-based mortar mixes at 3, 7, 28, 56, and 90 days. Mix M2 (with 10% CSSP, 20% GGBS) emerged as the optimum mix, achieving 48.5 MPa compressive strength at 90 days, with a minimal strength loss of 24.83% and 42.53% after 28 days immersion in sea water and 5% HCl solution and mass loss of 0.84% and 0.75% after 28 days immersion in sea water and 5% HCl solution, when compared with control mix. It was also observed that optimum mix M2 showed reduction in CO 2 emissions by 68.58%, along with reduction in cost of mortar by 22.78% proving it to be more economical and sustainable mortar mix as compared to control OPC mix. Graphical abstract