Hydrodemolition

Unlike what the name might suggest, hydrodemolition is not used so much for demolition projects as it is for surface restoration and protection projects. When concrete has deteriorated or the reinforcing steel has begun to corrode it is necessary to remove any unsound concrete and rebar in order to replace it with new concrete and maintain the integrity of the structure. This process has also been used to remove sound concrete, concrete that is not compromised in any way. This may be done to install a preventive [cathodic protection] system, or to remove concrete in structures in which vibration is a concern. Unlike jackhammers hydrodemolition does not produce vibrations throughout a structure and therefore does not introduce micro fractures.

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Applications

Hydrodemolition can be used for horizontal, vertical, and overhead concrete removal and surface preparation on reinforced and non-reinforced structures. It is effective in removing concrete from around embedded metal elements such as reinforcing steel, expansion joints, anchorages, conduits, shear connectors, and shear studs. Hydrodemolition can be used for localized removals where deterioration is confined to small areas and for large area removals in preparation for a bonded overlay. This technology can also be used to remove existing coatings from concrete. (International Concrete Repair Technical Guidelines No. 03737)

Hydro Scarification (a.k.a. Scarification)

The process of hydro scarifaction uses high pressure water to remove the top surface of a concrete bridge or road surface. Usually the removal is within 1/4" to 3/4" at the most, but the teminology can be used to describe removal of any depth of concrete above the top layer of rebar. Removal of the type is done in order to replace the top of a bridge deck or road surface with new sound concrete. Much like applying oil and chips to an asphalt road this helps extend the useful life of the bridge decking and road surface by delaying the need for complete replacement.

Structures

This technology has been used on the following types of structures: Bridge decks and substructures,
parking structures, dams and spillways, water treatment facilities, tunnels and
aqueducts, nuclear power plants, piers and docks, stadiums, warehouses, transfer stations, and retaining walls.

Safety

Any process that is powerful enough to cut concrete can cut skin and bone with little effort. Operators of hydrodemolition equipment are required to wear many types of Personal Protection Equipment. For robotic hydrodemolition equipment, the operator wears the standard steel toed boots, eye protection, earmuffs and hard hat. Hand lance operators wear steel toed boots, metatarsals, shin guards and sometimes body armor.

Related Processes

Hydrocleaning (a.k.a Surface Cleaning)

Surfaces of all types can get dirty from excessive use and abuse, water and air pollution and general exposure to the elements. These surfaces can be cleaned using high pressure water, high pressure water mixed with an abrasive, air propelled abrasives (Sand Blasting), as well as other methods. When high pressure water is used it's called hydrocleaning.

Coating & Sealant Surface Preparation

The use of high pressure and ultra high pressure water has been used to clean various coatings on concrete surfaces for the purpose of repair and reapplication. Coatings are used to protect concrete from the elements, rain, salt, and to create a friendlier surface for human use. Concrete can also be covered carpet or tiles using a heavy duty glue or mastic. High pressure water can be used to clean these materials off when new carpet or tiles are desired.

Rubber Removal

Commercial and Military airports are required to keep certain levels of friction on the landing strips in order to prevent planes from sliding off. Runway design, weather and amount of rubber on the runway all play a role in the level of friction of a landing strip. If too much rubber is present, especially in rainy weather, the friction of the landing strip will be lower requiring more distance for the plane to land. If there is more distance required to land than existing runway, the plane will end up going off the end of the runway. High pressure water can be used to remove rubber left from airplane tires and restore required friction levels in a process also known as hydrocleaning.