Maintenance is a much higher percentage of this total cost, so Dr Jonkers expects big savings through extending the concrete's service life.

BBC: Key test for re-healable concrete

But, in order to do so, says Dr Jonkers, "we have to apply a coating to the particles, which is very expensive".

BBC: Key test for re-healable concrete

"In the lab we have been able to show healing of cracks with a width of 0.5mm - two to three times higher than the norms state, " Dr Jonkers explained.

BBC: Key test for re-healable concrete