US: A team at the University of Princeton has developed a new alternative cement using oyster shells. The team says that the oyster shells provide calcium carbonate in the form of aragonite, along with biopolymers. Together, these raise the resulting cement’s crack resistance by 19% and its ductility by 17% compared with ordinary Portland cement (OPC).
Team leader Reza Moini said “Our bio-inspired approach is not to simply mimic nature’s microstructure, but to learn from the underlying principles and use that to inform the engineering of human-made materials. One of the key mechanisms that makes a nacreous shell tough is the sliding of the tablet at the nanometer level. Here, we focus on the mechanism of tablet sliding by engineering the built-in tabulated structure of cement paste in balance with the properties of the polymer and the interface between them. In other words, we intentionally engineer defects in the brittle materials as a way to make them stronger by design.“
