Concrete, the second most consumed material globally after water, has fueled an environmental and resource crisis, particularly concerning sand depletion. A groundbreaking study by Rice University researchers explores the potential of utilizing graphene, derived from metallurgical coke, not only as a reinforcing additive but also as a viable replacement for sand in concrete.
The study, led by James Tour, T. T. and W. F. Chao Professor of Chemistry, Materials Science, and Nanoengineering at Rice University, unveils a promising alternative to traditional sand-based concrete. The graphene aggregate substitute not only demonstrates comparable toughness but also reduces concrete weight by 25%.
The significance of this innovation lies in the environmental challenges posed by the concrete industry. With cement production contributing to 8% of global carbon dioxide emissions and unregulated sand mining threatening ecosystems, the demand for sustainable alternatives becomes crucial.
The researchers applied their signature Joule-heating technique to metallurgical coke, resulting in graphene that mirrors the size of sand. The subsequent experiments indicate that metallurgical coke-derived graphene can effectively replace sand in concrete, offering a practical solution to the impending “sand crisis.”
Comparative tests between conventional concrete and graphene-based concrete showcase not only matching mechanical properties but also an improved strength-to-weight ratio for the latter. The Flash Joule heating technique employed in this process enables faster and larger-scale graphene production compared to previous methods.
While acknowledging that the commercial viability of graphene is currently a challenge due to cost considerations, Tour emphasizes the importance of pursuing alternatives. Satish Nagarajaiah, a corresponding author on the study, underscores that approximately 30% of concrete comprises sand, making the search for alternatives imperative.
Supported by entities such as the U.S. Army Corps of Engineers, Engineer Research and Development Center, the Air Force Office of Scientific Research, and the National Science Foundation, this research signals a potential shift towards more sustainable urban development practices, aiming to mitigate the environmental impact of traditional concrete production.
Source: Rice University