Method and apparatus to remove structural concrete

Abstract

By the action of water jetted against the concrete in systematically controlled manner under ultra-high pressures (i.e. above 25,000 psi) areas of structural concrete are removed to required depths through the one or more levels of aggregate involved efficiently and with safety to the basic structure and to attendant personnel. With this method and apparatus employing an array of such jets scanned progressively back and forth over a work area, the rates at which requisite volumes of hardened concrete can be removed, regardless of condition or state of the concrete and the presence of reinforcing bars, are much greater than those customarily achieved with conventional methods. Moreover the operation can be performed without danger of cutting into and weakening embedded reinforcing bars, without damaging the concrete in adjoining regions, without dust pollution and with minimum noise levels that are also readily shieldable. The sequential penetrating and exploding action of the ultra-high pressure water entering between and beneath the aggregate particles not only removes the concrete immediately surrounding embedded reinforcing bars but is also effective to remove surface scale and corrosion from such bars, conditioning them to form a strong bond with fresh concrete to be poured around them. Moreover, incidence angle of the water jets to the concrete surface may be varied during scan so as to enhance the removal action in places otherwise difficult to reach, such as beneath and behind reinforcing bars or composites of such bars.