The incorporation of waste materials generated in many industries has been actively advocated for in the construction industry, since they have the capacity to lessen the pollution on dumpsites, mitigate environmental resource consumption, and establish a sustainable environment. This research has been conducted to determine the influence of different rice husk ash (RHA) concentrations on the fresh and mechanical properties of high-strength concrete. RHA was employed to partially replace the cement at 5%, 10%, 15%, and 20% by weight. Fresh properties, such as slump, compacting factor, density, and surface absorption, were determined. In contrast, its mechanical properties, such as compressive strength, splitting tensile strength and flexural strength, were assessed after 7, 28, and 60 days. In addition, the microstructural evaluation, initial surface absorption test, = environmental impact, and cost–benefit analysis were evaluated. The results show that the incorporation of RHA reduces the workability of fresh mixes, while enhancing their compressive, splitting, and flexural strength up to 7.16%, 7.03%, and 3.82%, respectively. Moreover, incorporating 10% of RHA provides the highest compressive strength, splitting tensile, and flexural strength, with an improved initial surface absorption and microstructural evaluation and greater eco-strength efficiencies. Finally, a relatively lower CO₂-eq (equivalent to kg CO₂) per MPa for RHA concrete indicates the significant positive impact due to the reduced Global Warming Potential (GWP). Thus, the current findings demonstrated that RHA can be used in the concrete industry as a possible revenue source for developing sustainable concretes with high performance.

The utilization of waste products is becoming a vital aspect of the construction industry to safeguard environmental assets and mitigate pollution, all of which lead to long-term sustainable development. From this perspective, this experimental investigation was carried out to determine the cumulative influence of waste glass cullet and metakaolin (MK) as partial replacements for coarse aggregates and cement in an isolated and combined manner. This research demonstrated the influence of integrating glass aggregate and metakaolin wherein coarse aggregate was substituted by 10%, 15%, 20%, 25%, and 30% glass cullet (by weight), and cement was supplemented with 10% metakaolin. The substitution of waste glass with coarse aggregate significantly declines the compressive strength correspondingly; however, the integration of 10% metakaolin powder enhanced the strength slightly for all specimens up to 25%. On the other hand, for flexural strength, the inclusion of glass waste in concrete reduced the performance, whereas the incorporation of metakaolin boosted the strength but did not achieve greater strength compared to the control mixture. The sustainability analysis revealed that the production cost and eCO₂ emission could be reduced by 15% and 7% by incorporating glass cullet and metakaolin in the concrete mix, which satisfied sustainability. Based on the experimental results, the ideal proportion substitution would be 25% glass aggregate with 10% metakaolin, which could satisfactorily be used to generate sustainable concrete.