Technology.am (Apr. 23, 2009) — The University of Michigan researchers developed a concrete material that can heal itself when it cracks. It needs just water and carbon dioxide.
Self-healing material is designed in such a way to bend and crack in narrow hairlines rather than breaks and split in wide gaps, as traditional concrete behaves.
The engineers observed that the cracks must be kept below 150 micrometers, and preferably below 50, for full healing. To fulfill this, researchers improved the bendable engineered cement composite (ECC) that acts more like metal than glass, where as traditional concrete is considered a ceramic that can suffer catastrophic failure when strained in an earthquake or by routine overuse, said Victor Li, the E. Benjamin Wylie Collegiate Professor of Civil Engineering and a professor of Materials Science and Engineering.
Flexible ECC bends without breaking because it is studded with specially-coated reinforcing fibers that hold it together. ECC remains intact and safe to use at tensile strains up to 5 percent. Traditional concrete fractures and can’t carry a load at .01 percent tensile strain.
Li’s self-healing concrete needs no steel reinforcement to keep crack width tight, so it eliminates corrosion.