In the quest for sustainable construction materials, a team of researchers led by Mohammad Reza Hanafi from the Department of Civil & Environmental Engineering at Amirkabir University of Technology in Tehran, Iran, has made a significant breakthrough. Their study, published in *Results in Engineering* (which translates to *Engineering Results*), explores the potential of sand washing waste (SWW) as a sole precursor for geopolymer mortar, offering a promising alternative to conventional cement-based materials.
Geopolymers, known for their low carbon footprint, are typically produced using industrial by-products like fly ash or blast furnace slag. However, this research takes a novel approach by utilizing SWW, a byproduct of sand washing plants, which has largely been overlooked in geopolymer production. “Despite growing research on industrial waste valorization, the direct application of SWW in geopolymer systems remains limited,” Hanafi explains. This study aims to change that by demonstrating the feasibility and benefits of using SWW as a single precursor.
The researchers combined sodium hydroxide (NaOH) activators with varying concentrations and water glass (WG) ratios to assess their effects on strength development and microstructural evolution. The optimized formulation with 12 M NaOH achieved a compressive strength of 27.3 MPa, indicating effective gel formation and structural densification. This strength is comparable to that of conventional cement-based materials, making it a viable alternative.
Microstructural analyses, including SEM, EDS, XRD, XPS, and NMR, verified the formation of a dense sodium aluminosilicate hydrate (NASH) gel network. This network contributes to enhanced durability and reduced porosity, addressing key challenges in the construction industry. “The formation of this dense NASH gel network is crucial for the performance and longevity of the geopolymer mortar,” Hanafi notes.
From a sustainability perspective, the study revealed over 50% reduction in CO₂ emissions and a 53% decrease in eco-costs compared with ordinary Portland cement. These findings highlight the potential of SWW-based geopolymers to support circular economy principles and sustainable construction applications.
The commercial implications of this research are substantial. The construction industry, particularly the energy sector, is increasingly focused on reducing its carbon footprint and adopting sustainable practices. By utilizing SWW, a readily available and often underutilized resource, construction companies can significantly cut costs and environmental impact. This innovation could lead to the development of new, eco-friendly construction materials that meet the growing demand for sustainable solutions.
Moreover, the successful application of SWW in geopolymer production could inspire further research into other industrial wastes, paving the way for a more circular and sustainable construction industry. As Hanafi suggests, “This study opens up new possibilities for the valorization of industrial waste and the development of high-performance, low-carbon binders.”
In conclusion, the research led by Mohammad Reza Hanafi offers a promising solution to the challenges of sustainability and waste management in the construction industry. By demonstrating the feasibility and benefits of using SWW as a single precursor for geopolymer mortar, this study sets the stage for future developments in sustainable construction materials. The findings, published in *Results in Engineering*, provide a solid foundation for further research and commercial applications, contributing to a more sustainable and circular economy.