Cracks in bridges and tunnels can cause major problems - but now scientists at Cambridge University might have found a solution - a self-healing form of concrete.
They are working in conjunction with the universities of Bath and Cardiff. Another self-healing method they are looking at in Cambridge is creating tiny capsules containing glue - that is mixed into the concrete.
When a crack appears it also breaks some of the capsules and the glue leaks out to seal up the crack.
Concrete is everywhere we look, it's been used in structures like motorways and tower blocks. So the scientists believe it could have a wide range of applications.
Click below to watch ITV News Anglia's full report on how the technology works: