What is Hydrodemolition?
Hydrodemolition is often referred to by many names and spellings – waterblasting, hydroblasting, high or ultra-high pressure water blasting, hydro-demolition, hydro-blasting – however, these terms all have one thing in common, and that is, concrete removal. Hydrodemolition uses high-velocity water jets to remove deteriorated, delaminated, or contaminated concrete from reinforced concrete structures such as bridges, dams and parking garages. Concrete is removed using ultra-high pressures (UHP – 35,000 psi) waterjets operating at velocities exceeding 1,500 mph. Using UHP water, our hydrodemolition process requires significantly less water than lower pressure systems, while providing ultra-high quality hydrodemolition. The use of less water helps protect the environment and conserve a valuable resource. Because no abrasive is used, the waterjets do not damage the reinforcing steel or other embedded metal items. As a hydrodemolition contractor, Rampart Hydro has been performing hydrodemolition, and it’s related services (water control, debris cleanup, and wastewater treatment) for more than 20 years throughout the United States and Canada. Continued below the pictures…
Types and Depths of Concrete Removal
(click on pictures for more information)
Hydrodemolition provides an excellent bonding surface, free from micro-fractures as well as many other benefits. Hydrodemolition is both an effective and efficient way to quickly remove deteriorated concrete and prepare the surface for the installation of a new concrete overlay or repair material.
Selective concrete removal is no problem for our UHP waterjets. Our powerful waterjets seeks out delaminated, deteriorated and low strength concrete and quickly removes the damaged concrete leaving an excellent bonding surface for the new overlay or repair material.
Computer-controlled waterjets can remove the concrete to provide a rough and bondable surface (Scarification, High-Speed, Fast Track Hydrodemolition). Bond test have proven that a monolithic slab is formed when new concrete is place over a surface prepared using hydrodemolition.
When delaminations have occurred within the top mat of reinforcing or if the concrete is sound but chloride contaminated, hydrodemolition can be used to expose the top mat of reinforcing (Partial Depth – Rebar Exposure) and remove all of the deteriorated and contaminated concrete. Typically the removal is to ¾” below the rebar allowing the rebar to be fully encased in new non-chloride containing concrete thus insuring the most durable repair possible).
Hydrodemolition can be used to remove concrete full depth (Full Depth), or deep within the concrete structure (Deep Removal), when it is necessary to protect the existing reinforcing, shear studs or other considerations. For bridge deck replacement projects, hydrodemolition is a great option. Rampart can quickly and easily remove concrete to facilitate the removal of deck slabs without damaging the embedded metal items that are required to remain.
Based on the project’s specifications, we program our machines to remove the concrete to the specified depth; however, our jets can remove deteriorated concrete below this depth, which further improves the structural integrity and longevity of the repair.
Demolition is only half of our job. Rampart has a fleet of vacuum trucks capable of collecting the debris and wastewater from the hydrodemolition process. We can also filter and reclaim the hydrodemolition wastewater and reduce the pH to acceptable levels so that it can be recycled or discharged in accordance with environmental regulations.
There are many advantages to using hydrodemolition over traditional removal methods, including:
- * The rough, irregular surface profile provides an excellent mechanical bond for all types of repair materials creating a monolithic repair:
- * The rough, irregular profile contains more surface area per square foot than any other type of concrete removal process;
- * Surface micro-fracturing (bruising) caused by mechanical removal methods are eliminated;
- * Exposed aggregates are not fractured, split or damaged and interlock with the overlay or repair material;
- * Lower strength and deteriorated concrete (delamination) is selectively removed;
- * Vibration to the surrounding structure is eliminated;
- * Reinforcing steel (rebar) is cleaned, eliminating the need for sandblasting;
- * Reinforcing and other embedded metal elements are undamaged.
- * Minimizes disruptions to users of occupied space by significantly reducing transmitted sound vibrations through the structure;
- * Increase speed of concrete removal, which can reduce construction time;
- * Minimizes dust and the potential for silicosis;
- * Robotic units reduce labor and minimize soft-tissue injuries compared to jackhammers.
- * Robotic equipment insures uniform removal.
Who uses Hydrodemolition?
Over 38 State Departments of Transportation;
US Army Corp of Engineers
Department of the Interior
City, County & State engineers
Structural Engineers across he US and Canada
All have experienced the significant advantages and benefits of hydrodemolition over traditional impact methods for concrete removal such as jack hamming and rotomilling.
What is a Hydrodemolition System?
A hydrodemolition system consists of:
- High-pressure water pump(s);
- A robotic cutting tractor; and
- A support vehicle or trailer.
Our ultra-high pressure pumps operate at 36,000 psi and either 32 gpm or 48 gpm. The robotic cutting tractor uniformly moves the waterjet over the surface controlling the quantity and quality of concrete removal. The support trailer transports the pumps, robotic tractor along with spare parts, tools fuel and water tanks to the project site.
What Controls Hydrodemolition Cutting Depth?
Simply stated, it is the length of time that the waterjet is directed at the concrete surface that determines the depth of removal, and contact time is controlled at the robotic cutting tractor.
There are five parameters that determine the quality and depth of removal.
- * Rotation speed of the nozzle
- * Angle of the nozzle to the surface
- * Height of the nozzle above the surface
- * Traverse speed
- * Advance distance
Rampart uses a variable speed-rotating nozzle, which can be adjusted from 0 to 1,800 rpm. In addition, the nozzle can be angled between 5° and 30° from vertical. When rotating, the angled water jet creates a demolition cone. By raising and lowering the nozzle the base of the cone can be increased and decreased in diameter. The robotic tractor moves the rotating nozzle back and forth on a traverse beam perpendicular to the direction of the tractor and tractor advances following a preset number and time for the traverse.
However, more important than how it is done is what it does? The robotic hydrodemolition process removes concrete in a safe, fast, predictable manner.
If you have a project and would like to discuss how hydrodemolition can help you or if you would like pricing or further information please contact us today.