The ubiquitous material known as concrete can be seen all around our modern world today, as its usage has paved the way for humanity’s greatest engineering projects—from the largest of skyscrapers to your own house down the road. However, concrete itself has a particularly pesky flaw when it comes to water—and Washington State University (WSU) researchers found a way to get around it using nanotechnology.
Ask your nearest builder and they will tell you how important it is to keep water out of concrete; its presence tends to ruin its structural integrity, after all. For example, the volume of water expands as it freezes into ice, placing the rigidity of the concrete in jeopardy.
The fact that concrete is a bit porous doesn’t help, either. As such, engineers use surface sealants to try and keep water out of concrete’s pores. These solutions, however, only work to a certain extent—or, at least, not if WSU researchers have anything to say about it.
The researchers’ unique solution involves incorporating certain nanomaterials into the sealant, including graphene oxide (GO) and nanoclay formed from a unique type of mineral known as montmorillonite. Their novel work was published in the Journal of Materials in Civil Engineering.
The two nanoscale additives were incorporated into a commercial-grade concrete sealant, and were then tested on actual concrete; the resulting concrete became roughly 75% more water-repellent compared to unmodified control samples. These treated concrete pieces were also found to be about 44% more resistant to salt damage that may be brought about by water carrying in dissolved corrosive salts into the concrete structure if left unabated. At the end of the study, the team found a 0.06% GO and a 0.15% montmorillonite, both by weight, to be the optimum recipe for the best-quality concrete sealant.
“We focused on one of the main culprits that [compromise] the integrity and durability of concrete, which is moisture,” said research lead and WSU Department of Civil and Environmental Engineering professor Xianming Shi in a WSU press release. “If you can keep concrete dry, the vast majority of durability problems would go away.”
Shi continued: “Traditionally when you switch from an organic solvent to water, you sacrifice the sealer’s performance. We demonstrated that the use of nanomaterials mitigates that reduction in performance.”
The next steps for Shi and co-author Zhipeng Li include optimizations to the sealant mixtures to improve their sealing performance. The duo also plans on conducting pilot-scale demonstrations of their novel work within the next two (2) years, including a concrete infrastructure experiment using the sealant.
References
- Coxworth, B. (2022, February 16). Surface sealant uses nanotech to make concrete last longer. New Atlas. https://newatlas.com/materials/surface-sealant-nanotech-concrete/
- Hilding, T. (2022, February 16). WSU-designed, nano-engineered sealer leads to more durable concrete [Washington State University]. WSU Insider. https://news.wsu.edu/press-release/2022/02/16/nano-engineered-sealer-leads-to-more-durable-concrete/
- Li, Z., & Shi, X. (2022). Effects of nanomaterials on engineering performance of a potassium methyl siliconate–based sealer for cementitious composite. Journal of Materials in Civil Engineering, 34(4), 04022006. https://doi.org/10.1061/(ASCE)MT.1943-5533.0004148
