There were several scenes in Terminator 2: Judgement Day in which the evil T-1000 was seemingly blown apart, only to pull together and reshape its liquid metal body. The cyborg could even shape-shift to become whatever form it chose. Now that’s a smart material. A scary example, sure, but actually not so far off from the types of materials being developed and used by various industries – including construction – today. Hopefully without the malicious intent.
Smart materials are engineered to respond to environmental stimuli such as temperature, pressure, and the presence of oxygen. Scientists from around the world are developing products once thought only possible using the magic of Hollywood. Below are 3 smart materials being developed to help make buildings and structures safer and more durable.
Concrete is a core building material. But even concrete starts to crumble when it comes face-to-face with water, wind, stress and pressure. The current method of dealing with structural instability in concrete has been to replace or repair it. But what if all you had to do was add a little water? A new type of smart concrete contains dormant bacteria spores and calcium lactate in self-contained pods. When these pods come into contact with water they create limestone, filling up the cracks and reinforcing the concrete. Self healing concrete is estimated to save up to 50% of concrete’s lifetime cost by eliminating the need for repair. Smart concrete is still being tested to determine how long the bacteria sustains itself, but researchers are hopeful they will be able to officially introduce smart concrete to the construction industry very soon.
The Terminator example above might make you a little skittish about shapeshifting metal, but all signs point to it having a dramatic benefit on the durability of skyscrapers, bridges and homes. Shapeshifting metals can undergo great stress and temporarily change shape, but they are designed to ‘remember’ their original form and revert back to it if altered in some way. Used in the construction of a bridge, for example, would help sustain the bridge against damage from a hurricane or earthquake. Practical use of this type of metal is largely still in the development phase, with scientists specifically studying how smart metal can be used by the construction industry. Companies like Shape Change Technologies LLC are leading the industry, with developments already being used by the medical community with an eye toward expanding their discoveries for use by engineers.
Self Healing Coatings
New to the market and already in use are self healing coatings, sealants and adhesives. A recent CNN.com article discussed U.S. based company Autonomic Materials and their development of self healing coatings being used on marine-based structures like ships and oil rigs. The coatings are made with polymers that innately react with one another when they rupture, creating a process of self healing. Autonomic Materials’ discovery is only for water-based structures, but the company is looking into developing materials for broader use by the construction industry.
Not yet in use, but in the process of being tested by a group of scientists, is a self healing coating that could be applied to concrete. The journal ACS Applied Materials & Interfaces recently wrote on the scientific discovery of this coating, but points out that it is not yet ready for industrial use. This material has the ability to self heal when it cracks and is exposed to sunlight, allowing UV rays to react with particles in the concrete that expand and then fill the cracks.
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