This research is focused on the development of an eco-friendly low-cost concrete using fly ash (FA) and marble powder waste (MPW) as partial replacements for cement and fine aggregate respectively. The substantial use of cement in concrete makes it expensive and contributes to global warming due to high carbon emissions. Thus, using such waste materials can help reduce the overall carbon footprint. For this purpose, various mix designs of concrete were developed by varying the percentages of FA and MPW. The concrete's fresh and hardened properties were experimentally determined for those mixes. The test results revealed that MPW as a sand substitute increases strength up to 40% and gradually decreases beyond that, but a 60% replacement still has more strength than the control specimen. Similarly, using FA as a cement replacement was found to reduce the strength, but the reduction was not very significant up to 20%. A mixed blend of FA and MPW showed superior results and maximum strength was obtained at F10M40. The optimal mix, with 10% FA and 40% MPW (F10M40), achieved a compressive strength of 4493.46 psi, a 16.21% improvement compared to the control mix proportion. Furthermore, the microstructure of the cementitious material was improved due to the pozzolanic reaction that led to a denser microstructure, as supported by the permeability test and SEM analysis.

The global construction industry faces a crucial challenge reconciling economic growth with environmental sustainability, notably due to the significant environmental impact of cement production, particularly in countries like Pakistan. As the demand for cement grows, so does the carbon footprint and environmental degradation, necessitating the exploration of sustainable alternatives like sugarcane bagasse ash (SBA), a byproduct of sugarcane processing, to mitigate these issues while also addressing rising costs in concrete production. Embracing SBA offers a promising avenue to alleviate environmental concerns and enhance the sustainability of the construction sector. This study investigated the SBA properties and effectiveness as a viscosity modifying agent (VMA) in self-compacting concrete (SCC), examining varying SBA content effects on fresh and hardened SCC properties. The hydration and microstructure properties were evaluated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) to investigate SBA-based SCC. The results indicate that SBA has the potential to enhance mechanical and microstructural properties by possibly increasing the formation of Calcium Silicate Hydrate (CSH) gel. Adding 5% SBA demonstrated favorable fresh properties while incorporating up to 15% SBA showed improvements in compressive strength. Overall, adding SBA to cement manufacturing during clinkerization can reduce environmental pollution and lower production costs.