In the quest for sustainable construction materials, a groundbreaking study from Clarkson University is challenging the status quo of the concrete industry. Led by Shubham Mishra, a researcher at Clarkson University in Potsdam, NY, the study explores the potential of unconventional precursors for creating alkali-activated concretes (UAACs) that not only reduce environmental impact but also mitigate the alkali-silica reaction (ASR), a common durability issue in concrete structures.
The research, published in the journal Cleaner Materials (translated from English as Cleaner Materials), delves into the use of materials like calcined low-purity kaolinitic clays, volcanic ashes, coal bottom ash, and fluidized bed combustion ashes as alternatives to traditional portland cement. These materials, often considered waste products from industrial processes, are being repurposed to create more durable and eco-friendly concrete mixtures.
The alkali-silica reaction is a significant concern in the construction industry, particularly for energy infrastructure. ASR occurs when the alkali in cement reacts with certain types of aggregate, leading to expansion and cracking. This can severely compromise the structural integrity of buildings, bridges, and other critical infrastructure, including energy facilities. Mishra’s research offers a promising solution to this problem.
“We found that most of the UAACs we tested showed significantly lower ASR expansion than traditional portland cement mixtures,” Mishra explained. “This suggests that these materials could be viable alternatives for creating ASR-resistant concrete.”
The study employed the Miniature Concrete Prism Test (MCPT) to evaluate the ASR performance of the UAACs across various aggregate reactivities. The results were compelling: the UAACs generated fewer and less viscous ASR gels, with high alumina uptake and negligible levels of calcium, enhancing their resilience against ASR.
But the innovations don’t stop at ASR mitigation. The research also explored complementary non-invasive assessments, such as electrical resistivity, pore solution analysis, and pore structure analysis, to predict ASR susceptibility. These rapid peripheral indicators could revolutionize the way the industry approaches ASR testing, making it faster and more cost-effective.
“Standard electrical resistivity measurements were strongly correlated with reduced ASR expansion in UAACs,” Mishra noted. “This could allow for more efficient and accurate ASR forecasting without the need for extensive testing.”
The implications for the energy sector are substantial. Energy infrastructure often requires concrete structures that can withstand harsh conditions and maintain durability over long periods. The use of UAACs could enhance the longevity of these structures, reducing maintenance costs and improving overall safety. Moreover, the environmental benefits of using industrial by-products as concrete precursors align with the growing demand for sustainable practices in the energy industry.
As the construction industry continues to seek more sustainable and durable materials, Mishra’s research offers a glimpse into the future. The use of unconventional precursors for UAACs could pave the way for new standards in concrete production, benefiting not only the construction industry but also the broader energy sector. The findings published in Cleaner Materials provide a solid foundation for further exploration and application of these innovative materials, potentially reshaping the landscape of sustainable construction.
