Concrete that Heals Itself

Out-of-this-world ways to solve one of the flooring and construction industry’s most persistent challenges

Grace Cathedral sits atop Nob Hill, on the site of the former Charles Crocker Mansion, which is destroyed in the great San Francisco earthquake of 1906. The third-largest Episcopal cathedral in the United States and open to visitors from all over the world, construction of the concrete and steel complex takes 54 years to complete, and includes the building of the Great Stairway to an exact-size replica of Ghiberti’s world-famous “Gates of Paradise” in Florence, Italy, a new Chapter House, outdoor courtyard labyrinth and a second labyrinth inside; twin towers, high roof and curved top inspired by Notre Dame in Paris as well as light-catching stained glass windows. Grace Cathedral is one the city’s beloved attractions, and one of California’s treasures.

As any high-performance flooring specialist can imagine, cracks in concrete are of great concern to a building as … well, as concrete as this one (forgive us). Cement is the world’s most widely used building material and cracks lead to moisture leaks that weaken steel support systems, causing serious damage or even collapse. Not to mention, delaminating mortar and damage to the floors. Concrete cracks seem unavoidable …

Until now.

BioConcrete Set for 2016 Release

Microbiologist Henk Jonkers and Eric Schlangen, who specializes in concrete development, have been conducting research for several years at Delft Technical University on a new type of concrete with self-repairing properties. The result is an invention called bioconcrete, with the power to heal its own cracks.

Jonkers and Schlangen incorporate the Bacillus genus bacteria inside biodegradable capsules along with the nutrient calcium lactate and then mix it into cement. Once a crack forms and water reaches the capsules, a little bit of science fiction occurs. The bacteria microbes come out of a dormant state and multiply, with the help of calcium lactate. The calcium lactate turns into calcite -pure limestone- and helps seal the crack.

Dr. Jonkers reports that bioconcrete is healing cracks as large as 0.5mm in the lab. Additional testing in huge quantities, types of concrete and different construction scenarios have led the researchers to develop a spray version of bioconcrete slated for release this year that can be applied to existing cracks. Expect the use of full-on bioconcrete for construction projects as early as 2016.

Self-Repairing Polymers

Meanwhile, researchers Biswajit Ghosh and Marek Urban are hard at work at the University of Southern Mississippi developing self-repairing polymers that heal themselves when exposed to sunlight. Composed of scratch-resistant polyurethane, oxetane (OXE) and chitosan (CHI), the new polymers work when OXE bleeds out into nicks in the polyurethane, chemically bonding with the CHI to fill the gap when exposed to ultraviolet (UV) radiation such as sunlight.

Researchers at Case Western Reserve University also created a self-healing polymer that works as a coating and seals surface scratches on things like cars and dining room tables –and needs UV light to heal.

Whatever magic these scientists are creating, this breakthrough could allow them to produce stronger sealants, paints, adhesives and more for use on floors, screens, lenses and other products where scratches can degrade performance, self-repairing composite material has also been designed for use in aircrafts. The first self-healing polymer was created several years ago by researchers at the CIDETEC Centre for Electrochemical Technologies in San Sebastian, Spain – this polymer can bind itself back together all on its own after being sliced with a razor blade.

Science fiction or answered prayers?

We’ll just wait and see …

About Surface Solutions

Recognized as a top UCRETE® Master Contractor since 2012, Surface Solutions is an independent industrial floor contractor specializing in seamless, polymer flooring systems utilizing the most trusted brands in the industry. From testing to consultation and complete installation services, Surface Solutions is your premier source of non-toxic, safe and environmentally friendly flooring systems, offering turnkey installations using only in-house personnel. All installations come with a complete single-source warranty.

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