In the heart of Shaoxing, China, a team of researchers led by Hongyu Tao from Yuanpei College, Shaoxing University, is turning the tables on construction waste, transforming what was once discarded into a valuable resource. Their recent study, published in *Materials Today Sustainability* (which translates to *Materials Today Sustainability* in English), explores the potential of recycled cement powder and glass powder to create low-carbon, environmentally friendly mortar. The findings could reshape the construction industry’s approach to waste and sustainability.
The construction industry is no stranger to waste. Every year, tons of cement pastes and glass are generated as by-products during building demolition, often ending up in landfills or open accumulations, causing resource wastage and environmental pollution. Tao and his team saw an opportunity in this challenge. “We wanted to find a way to utilize these waste materials effectively,” Tao explains. “Not only to reduce waste but also to enhance the performance of mortar.”
Their solution? Composite supplementary cementitious materials (RCG), formulated by mixing recycled cement paste and glass powder. By partially substituting conventional cement with RCG, the team prepared environmentally friendly mortar and studied its mechanical properties, microstructure, and nanomechanical properties.
The results were promising. Incorporating an optimal proportion of RCG (10%–20%) enhanced the mechanical properties of the mortar. “We observed a significant improvement in compressive strength,” Tao reveals. “The RCG20 specimen, for instance, showed a 5.79% increase in compressive strength at 28 days compared to the control specimen.” However, the strength of specimens decreased with a further increase in RCG content, indicating a sweet spot for optimal performance.
The addition of RCG also improved the compactness of mortar specimens, optimized the pore structure, and increased the C-S-H (calcium silicate hydrate) content, particularly high-density C-S-H. This is a crucial finding, as C-S-H is a key component in the strength and durability of concrete.
From an environmental perspective, RCG-containing mortar has lower CO2 emissions and cost compared to conventional mortar. This is a significant advantage, given the construction industry’s substantial carbon footprint. “Our study highlights the potential for resource recovery from construction waste,” Tao states. “This contributes to the sustainable development of cement-based materials.”
The commercial implications for the energy sector are substantial. As the world grapples with climate change and strives for sustainability, innovative solutions like RCG can help reduce the environmental impact of construction. Moreover, the cost savings from using recycled materials can make construction projects more affordable, benefiting both developers and end-users.
This research could shape future developments in the field by encouraging the construction industry to adopt circular economy principles. By turning waste into a resource, construction companies can reduce their environmental impact, lower costs, and contribute to a more sustainable future.
As Tao and his team continue to explore the potential of RCG, one thing is clear: the future of construction is not just about building upwards, but also about looking downwards, at the waste beneath our feet, and finding innovative ways to use it. This study is a testament to the power of sustainable innovation and a call to action for the construction industry to embrace a greener, more sustainable future.