Metakaolin-based ultra-high-performance geopolymer concrete, role of basalt, glass, granite, and marble waste powders

Recycling solid waste is an economical path to protect the environment’s resources, shield the ecosystems, and reduce the need for raw materials. Ultra-high-performance geopolymer concrete (UHPGC)-based waste materials (WMs) were developed to achieve better mechanical performance with more economic and ecological benefits. This study aims to assess how powdered waste materials (PWMs) affect the performance of UHPGC as an environmentally friendly material. Overall, twenty-nine specimens were included with granite waste powder (GWP), basalt waste powder (BWP), waste glass powder (WGP), and marble waste powder (MWP). The workability, splitting tensile strength, compressive strength, and flexural strength were evaluated through experiments. Additionally, the durability and microstructure properties of PWMs-based UHPGC were investigated using the sorptivity test, elevated temperature resistance, SEM, and XRF. Three systems (solo, hybrid, and trinary) were used to add PWMs at four doses (25%, 50%, 75%, and 100%) to replace fine aggregates entirely or partially. Thirty percent of the binding materials were replaced with GWP to create the mixtures. The results of the studies showed that the ideal dosage for improving the mechanical and microstructural properties of PWMs-based UHPGC was the optimal substitution ratio, employing the trinary system with 33% of WGP, MWP, and BWP, was 25% at 90 d. The features decrease noticeably when the replacement ratio rises to 100%. The study’s findings, therefore, demonstrated that PWMs may be effectively employed in UHPGC while still producing concrete with sufficient characteristics for various applications.