Light showers and concrete

A composite concrete material riddled with tiny fibers can fix itself when it next rains. The material could be a boon to structural engineers and those charged with maintaining civil infrastructure in earthquake zones. University of Michigan researchers say the self-healing material just needs light drizzle and carbon dioxide to fix any hairline cracks that appear. The new type of concrete, developed by Victor Li and colleagues, is slightly flexible and so does not break apart under extreme stress. Instead it flexes and when it reverts to its original state any hairline cracks that have formed heal.