Recycling of waste marble powder and waste colemanite in ternary-blended green geopolymer composites: Mechanical, durability and microstructural properties

The objective of this investigation was to identify the effects of curing temperature, cement clinker aggregate, waste colemanite (WCM) and waste marble powder (WMP), as well as their interaction, on the early physico-mechanical properties, microstructure, and high-temperature resistance of geopolymer composites (GC). Ground granulated blast furnace slag (GBFS), metakaolin (MK), and silica fume (SF) were employed as precursors for the production of GC. These materials were activated using a solution of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). In the fabrication of the GC, fillers such as WMP, WCM, and cement clinker aggregate (CCA) were employed. Four GC mixes were generated and cured for 8 h at curing temperatures of ambient (20 & DEG;C), 60 & DEG;C, and 90 & DEG;C. Investigations were conducted into how curing temperature, WMP, and CCA affected the GC's compressive, flexural strength, water absorption, dry unit weight, porosity, and sorptivity. The resulting mixes' performance at high temperatures was also assessed. Using SEM, microstructure investigations of GC mixes made for the study were also carried out. The obtained results indicated that the mixture M2 containing 100 kg/m3 of WMP and 750 kg/m3 of CCA exhibited the greatest compressive strength of 24.60, 55.60 and 68.80 MPa at ambient, 60 & DEG;C and 90 & DEG;C respectively compared the other GC mixtures. Moreover, the compressive strength of the M1 mixture enhanced by 190.65% and 239.56%, at 60 & DEG;C and 90 & DEG;C respectively compared to ambient-cured samples. Ambient cured mixture M4 that contains maximum WBM and minimum CCA content exhibited the strength enhancement of 54.01, 46.52 and 29.95% at 150, 350, and 550 & DEG;C respectively.