Many structures around the region are suffering from "concrete cancer", caused by chloride attack on the steel rebars causing them to corrode, expand, and crack the surrounding concrete.

Hydrodemolition is rapidly becoming the proffered method of removing damaged and contaminated concrete from structures for repair purposes.

A high pressure water jet is directed at the surface, and penetrates the cement/fines matrix surrounding the aggregate, which is then forced out by the hydrostatic pressure. Where cracks are present, the water jet penetrates along the crack resulting in higher removal rates, and selective removal of damaged areas.

Unlike mechanical methods such as jack hammering, Hydrodemolition does not create any macro or micro cracks in the remaining material, leaving a clean, sound surface with excellent bonding properties for the new material.

Reinforcing steel is left cleaned, but undamaged, and since there is no vibration acting on the steel, there is no danger of damaging the bond with the concrete in adjacent sound areas and creating the right conditions for further corrosion, as is the case with mechanical methods.

Hydrodemolition on a bridge deck

Hydrodemolition on a vertical wall. Note how the concrete has been removed leaving the rebars intact.

Hydrodemolition on the curved roof of a tunnel