When you think there is nothing new, an idea that will improve a key component of our business comes forth. The product, this time, is concrete, essentially unchanged (other than admixture tweaks) since the days of the Roman Empire, yet we use it every day
The new idea involves carbon, a fundamental element. Graphene is one of the many pure forms of carbon, such as the “lead” in your pencil or the diamond on your beloved’s left ring finger. Graphene is fast becoming a star in construction through water filtrations systems, paints, plastics, and adhesives.
Carbon makes up only about 0.025 percent of Earth’s crust—yet it forms more compounds (more than 10 million at last count) than all the other 93 natural elements combined. It is also the most despised element, at least in the minds of environmental regulators, determined to stamp out various carbon compounds such as carbon dioxide—the gas we all exhale when still breathing.
Materials scientists are not worried about the constant assault on carbon. A recent article from the Australian website New Atlas highlighted the new role of carbon as a research team at Northwestern University, Evanston, Ill., looked to shore up the strength and durability of concrete. They turned to graphene, a single layer of carbon atoms bonded together in a simple honeycomb-like structure.
The recent collapse of a condo building in the South Beach area of Miami, Fla., highlighted one of the main reasons concrete structures fail—the formation of cracks, which start as tiny ruptures. Once water infiltrates these cracks, the concrete deteriorates, the building, bridge or roadbed is doomed.
Adding graphene to a concrete mixture is the latest effort to intervene in this process to create “self-healing” concrete that patches cracks. Other approaches have included blood enzymes, fungus and special glues.
The experiments allowed the scientists to fine-tune the makeup of the cement to enhance its performance. Through this process, the team selected graphene nanoplatelets as the winning ingredient, which they found could be incorporated in small amounts to improve the fracture resistance of the finished product. Northwestern researchers achieved this goal by lowering the material’s porosity and water penetration, which decreased by 78 percent
Nanoplatelets are commercially available now. We can hope this research will lead to a product that our contractors can use in their work. It’s time for a 21st Century improvement that will better the material we inherited from the Romans.
By Garrett Francis, ECA President Email: [email protected]