Look at any concrete bridge, sidewalk or wall you come across, and you’ll probably see cracks of all shapes and sizes. Fixing these cracks is a common construction job. It’s also time-consuming, labor-intensive and expensive. With countless millions of cubic yards of concrete covering the planet, that’s a whole lot of surface area for cracks to form. Even though concrete is frequently invoked as a metaphor for strength or hardness, it’s prone to cracking because it actually has surprisingly low tensile strength. When concrete begins to crack, water, gasses and other debris start to seep in through microcracks, which eventually become bigger cracks, which, if left unrepaired, eventually undermine the structural integrity of the entire surface, right down to the reinforcement. This creates potentially dangerous conditions, up to and including total collapse. But as per usual, science has found a way.
With countless millions of cubic yards of concrete covering the planet, that’s a whole lot of surface area for cracks to form.
Enter Dutch microbiologist and professor Henrik Jonkers, who has created “Bio-concrete”, a biological-based form of self-healing concrete that is actually able to self-repair cracks once formed, and the potential applications are nothing short of groundbreaking (pun very much intended.)
The method involves adding hollow pellets filled with bacterial spores to the concrete mixture. As water eventually seeps into the concrete (and it will), the pellets rupture and the bacteria “awakens” to produce calcium carbonate (limestone), which, as if by magic, begins to fill in the cracks. The process can take as little as three weeks to heal concrete fissures, even holes too large to be considered merely cracks, and the bacteria itself can last up to 200 years in a dormant state. The bacteria pose no threat to humans, as it can only survive within the concrete. When the bacteria are roused from their slumber after coming into contact with water, it comes to life and the process begins. It consumes oxygen, which halts the corrosion of reinforced concrete from within.
This miraculous innovation could save billions of dollars in construction costs and untold hours of labor, particularly on surfaces frequently exposed to extreme weathering conditions, where manual repairs are currently the only practical solution in use today. Concrete is far and away the world’s most common construction material, and the cost of routinely repairing concrete structures, types of which there are too many to name, can be obscenely expensive and time-consuming in the long term, particularly as the structure ages. Jonkers’ Bio-concrete has applications that could forever change the construction industry, potentially eliminating the need for recurring maintenance on cracked concrete, saving countless hardworking backs in the process.
Bio-concrete could also go a long way in reducing the carbon footprint produced by the construction industry.
For now, Jonkers’ miracle concrete remains prohibitively expensive for widespread use (about $33-44 per square meter, according to Smithsonian magazine), but he and his team are working on a cheaper, sugar-based alternative, which should eventually make it more wallet-friendly and ready for mass adoption as demand for it increases.
Bio-concrete could also go a long way in reducing the carbon footprint produced by the construction industry. According to Columbia University’s Earth Institute, the production of cement alone accounts for 5 percent of global carbon dioxide emissions.
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