No more potholes! 'Living' concrete heals itself using BACTERIA when it comes into contact with water Building repairs and potholes cost billions every year - and that's not to mention the amount of roadworks created by ongoing maintenance.But the days of crumbling structures and potholed roads are numbered after a microbiologist developed a self-healing concrete that mends cracks using bacteria.And this bacteria can also be added to a liquid and sprayed onto existing cracks formed by decades of wear and tear, as well as onto other materials. 
Using a type of bacteria that is typically found near active volcanoes, researchers mix them into the concrete along with calcium lactate. When cracks in the concrete appear, and water enters them, the water 'awakens' the bacteria (animated). The bacteria 'eat' the calcium lactate and secrete limestone which closes the cracksIn conventional, reinforced concrete stress gradually creates small cracks. Water penetrates the steel in the concrete which starts to rust and becomes brittle.Using a type of bacteria that is typically found near active volcanoes, and near soda lakes like those near Wadi Natrun in Egypt, the researchers mix the bio material into the concrete as it is made.The bacteria are heat and cold resistant. 'The bacteria live in nature, usually in stones,' explained inventor Hendrik Marius Jonkers from Delft University of Technology. 'The special thing about them is that they form spore meaning they are well suited to the concrete because they can survive for a long time.' The bacteria, along with calcium lactate, is mixed with water and concrete components.When cracks in the concrete appear, and water enters them, the water 'awakens' the bacteria - which can lie dormant for 200 years.Once active, the bacteria 'eat' the calcium lactate and secret limestone which closes the cracks.It takes three weeks for the bacteria to seal the cracks, and there is no limit to the length of the crack the material can fix. However, the width of the crack has to be 0.8mm wide or thinner for the process to work effectively. The process also works on existing buildings and roads thanks to a special liquid containing the bacteria that can be sprayed onto cracks.Dr Jonkers plans to release the spray later this year and launch the concrete in 2016 - although an exact date hasn't been released.'The concrete [is] perfect for structures which are difficult to maintain, like underground buildings, motorways or oil rigs,' added Dr Jonkers.'It is extremely durable. The bacteria are specially adapted to extremely alkaline environments, and can survive dormant inside the concrete for years. The team has been nominated for a European Inventor Award.