Hydrodemolition, also known as hydroblasting or hydromilling, is a demolition method used to remove concrete and other materials using high pressure or ultra high-pressure water jet. Compared to conventional demolition tools, hydrodemolition is an effective method to cut down concrete without affecting the substructure and other parts.
Hence, this approach is accurate and has less impact on the surrounding substances. It is safe and reduces the risk of workplace injuries. The hydrodemolition process does not involve vibrations, unlike other techniques.
This article explores the historical background, key features, and advantages of hydrodemolition in the construction industry.
Researchers, McCurrich and Browne (1972) made the first serious attempt to use water jets for concrete hydrodemolition. They found that cutting of concrete using water jet consumes less energy. From the initial studies, they inferred the following results:
It then took them ten more years to overcome the abovementioned flaws and develop a commercial hydrodemolition unit. Contradictory to the above information, modern hydrodemolition systems work at operating pressures of about 100 MPa. It is 30% of the threshold suggested by McCurrisch and Browne (1972).
At present, hydrodemolition is widely used to clean, remove, drill, profile, and demolish concrete substrates and reinforced concrete structures. Hydrodemolition is a state-of-the-art technique in concrete technology and structural rehabilitation.
Hydrodemolition, in general, can be called as a selective demolition method that involves removing damaged or low-strength concrete while keeping intact the healthy concrete. It is an efficient, cost-effective, and precise method that employs high-pressure water to remove deteriorated concrete.
It has no risks of microcracks of the existing substrate compared with other traditional approaches. Hydrodemolition is a secure and controlled solution for the removal of concrete. It is widely used to prepare bridges before placing the deck overlay to achieve high bonding.
The process is much gentler to the environment. It involves pressure jetting, which is silent compared to heavy-duty machinery. This hence helps to reduce acoustic impact on the surrounding area. The water jet systems used in hydrodemolition are a zero-dust activity that reduce air pollution to negligible levels.
Hydrodemolition is performed using hydrodemolition machines that use either high-pressure or ultra-high pressure (UHP) water jets. This can be accomplished by three approaches:
Ultra-high pressure water jets are used in hydroscarification, which involves the removal of the top layer of concrete. The depth generally falls between 1/4 to 3/4 inches.
Partial depth removal involves selective removal of concrete that has a depth greater than 3/4 inches.
Full-depth removal involves the demolition of the entire deteriorated concrete.
The high-pressure water jetting has a pressure of around 15,000 to 25000 psi, and UHP possesses pressures in the range of 25,000 to 55,000 psi.
The equipment used for hydrodemolition is automatic such as a robotic cutting tractor. These robots are programmed to control the water jets to help uniform removal of concrete. Along with these robots, trailors and water pumps are used to collect and transport water.
The major fields for application of hydrodemolition are:
The key benefits of hydrodemolition are:
Major drawbacks of hydrodemolition are:
Hydrodemolition is a demolishing method used to remove concrete and other materials using high pressure or ultra high-pressure water jet. Compared to conventional instruments, hydrodemolition is an effective method to cut down the concrete without affecting substructures and other parts.
Bridge and parking deck repair 2. The main applications of hydrodemolition are: 1. Decommissioning 3. Decontamination 4. Construction joint cleaning 5. Tunnel rehabilitation Road maintenance 6.