hydrodemolition

Hydrodemolition is a concrete removal technique that uses high-pressure water jets to erode and remove concrete while minimizing damage to embedded reinforcement. The process directs a focused jet at the surface, typically delivered by a robotic arm or dedicated machine, for controlled removal to a prescribed depth. By concentrating the erosive action on the cement paste and weaker aggregate around the steel reinforcement, hydrodemolition can expose or recover rebars without inducing the extensive cracking associated with mechanical demolition.

Equipment and operation involve high-pressure water pumps, specialized nozzle heads, and a guiding system such as a robotic arm, track, or crane-mounted rig. The nozzle traverses the target area to remove deteriorated concrete, coatings, or laitance. The operation produces a slurry of water and concrete fines that must be collected, filtered, and treated to minimize environmental impact.

Applications include bridge deck rehabilitation, tunnel linings, parking structures, and other concrete infrastructure where selective removal is required. It is used to remove damaged concrete, prepare surfaces for bonding, and provide a roughened profile that improves adhesion for subsequent repairs.

Advantages of hydrodemolition include precision and selectivity, minimal vibration and dust generation, preservation of surrounding reinforcement, and the ability to expose steel for rehabilitation or inspection. Limitations consist of high equipment and operating costs, substantial water usage and wastewater management requirements, and the need for skilled operators. The technique may be less suitable for confined spaces or intricate geometries and requires appropriate containment and environmental controls for slurry disposal.