The Penn Hydro Way.
Penn Hydro utilizes state of the art hydrodemolition machines to provide exceptional safety and production. The industry refers to these machines as “robots”. Each robot is remote controlled, and adjustable on the fly to maximize efficiency and productivity. Penn Hydro utilizes a variety of attachments to maximize quality and production speed. Attachments include oscillation heads, rotation heads, scarifying heads, and arm attachments. All of which have been developed, deployed, and proven from our highly experienced field personnel. Each robot is accompanied with a pump unit to minimize the job site foot print. This is critical for creating a safe working environment and reducing risk. Each pump unit has an advanced pressure sensor that will shut down automatically if a high-pressure line fails. This prevents high-pressure lines from “whipping” around uncontrollably in the unlikely event a failure occurs. For additional safety, Penn Hydro utilizes whip checks at every connection point of the high-pressure line. Additionally, each robot is equipped with an emergency stop that will immediately stop the system in case of emergency. Furthermore, every pump in Penn Hydro’s fleet is equipped with an emergency stop button that will immediately stop the system in case of emergency. Why so much safety? Penn Hydro not only believes in safe working environments, but that increased safety leads to better production and focused field personnel to provide unmatched levels of quality.
What Is Hydrodemolition?
What is hydrodemolition? Hydrodemolition is a concrete removal process that involves using ultra high-pressure water jet systems for removing deteriorated concrete and sound concrete. Hydrodemolition can be used for horizontal, vertical, and overhead removals. This method can be used on reinforced and non-reinforced structures. Hydrodemolition is highly effective when removing concrete from embedded metals such as shear studs, shear connectors, anchorages, conduits, expansion joint hardware, and reinforcing steel. The effects of hydrodemolition can be controlled to localized areas where specific length and widths of removal might be required. This process can also be used to remove coatings from concrete surfaces, and prepare concrete surfaces for bonded overlays. Types of projects hydrodemolition is used for include:
Bridge Deck and Substructures
Dams and Spillways
Water Treatment Facilities
Tunnels and Aquaducts
Nuclear Power Plants
Piers and Docks
Hydrodemolition Technical Benefits
Mechanical methods, such as concrete breakers, rotomills, scabblers, and scarifiers, remove concrete by impacting the surface. These methods crush, fracture, split aggregate, and cause microfractures in the substrate.The end result is the leftover concrete may be compromised, and may require additional repairs for adequate bonding. Mechanical removal methods will also cause damage to reinforcing steel, conduits, shear stud connectors, and expansion joint hardware. Vibrations can also cause further microcracking, and noise. The hydrodemolition process causes erosion of the cement paste around the aggregate, which leaves a rough surface that is optimal for bonding. This process eliminates micro cracking, and unwanted vibrations as the water jet does not create a mechanical impact. Thus reducing and preventing vibrations from being transmitted throughout the structure. Hydrodemolition also provides a rough and irregular surface profile, which allows for optimum bonding of new material. Rotomills, scarifiers, and jackhammers remove concrete to a uniform depth and may leave deteriorated concrete below a specified depth. Hydrodemolition moves in a consistent pattern over the surface and may remove deteriorated concrete below the specified depth. The rough and irregular surface profile provided by hydrodemolition will result in high bond strengths.
Standard Types of Removal
Scarification is used to provide a rough profile for bonding new material. Scarification is often used for preparation before applying concrete overlays. However, this method can be used for other applications that require a rough bonding profile for adherence. Scarification may not remove delaminated concrete due to the high speed that the water jet moves over the surface. It’s important to inspect the area after scarification and identify any delaminated or deteriorated areas for further removal. Corroded reinforced steel that was exposed during the scarification process will indicate that there might have been a lack of concrete cover, the presence of chloride contamination or carbonation, or both. It’s important to remove the concrete around the corroding steel to ensure the repair is optimized.
Partial Depth Removal
Partial depth removal is commonly used to expose the top rebar mat. This is required if chloride contamination, deterioration, delamination, and or spalling has occurred on the top mat of the reinforcing steel. Partial depth concrete removal can expose the top mat of reinforcing steel and provide minimum clearance of 0.75in (19mm) below the bottom of reinforcing steel. It is important to determine the size of the reinforcing steel and concrete cover in order to specify the removal depth. Detail chipping and or hand lance might be required to obtain depth uniformity across the surface.
Full Depth Removal
Full-depth removal is used to remove all concrete without harming the reinforced steel. This is typically used in areas where delamination has occurred in the lower mat of reinforcing or chloride contamination exists throughout the entire thickness of the slab/structure. Structural elements such as shear studs, rebar, steel beam, and flanges are examples of steel reinforcements that can be exposed without damage. The removal rate slows as the depth increases because the water jet stream dissipates as it moves away from the nozzle; the water jet must push more water and debris from its path prior to contacting the surface to be removed.
Coating removal can be achieved with the hydrodemolition process. Hydrodemoliton can be used to remove epoxy, urethane, hot-applied, paint, and other coatings from concrete surfaces. Typically a multi jet nozzle is used to conduct removal. The multi jet nozzle will prevent the water from penetrating the concrete.
Hydrodemoliton has a multitude of different applications. The industry has tried to define most cases where hydrodemolition is applicable. However there are different applications that are not specified such as rubber removal, concrete surface washes, and many more applications. Hydrodemolition typically provides a fast solution. However, sometimes it is beneficial to set up a demonstration in order to fully understand if it is the necessary route to take for a specialty removal.