Even the tiniest cracks on the surfaces of concrete structures can lead to big problems if they aren’t immediately repaired. Now researchers have demonstrated a sunlight-induced, self-healing protective coating designed to fix cracks on the surface of concrete structures before they grow into larger ones that compromise structural integrity.

More resilient concrete structures like bridges and overpasses could save governments billions of dollars in annual expenses on repairs and maintenance. In recent years, a growing field of research has focused on developing self-healing mechanisms for a range of materials, concrete included.