In situations where concrete needs to be broken but at the same time you want to protect the rebar from damage, high-pressure waterjet technology offers an ideal solution. This technology uses a high-pressure jet of water generated by a high-pressure pump to crush concrete.
By adjusting the pressure and flow of the water jet, the depth and extent of the concrete can be precisely controlled, thus avoiding damage to the rebar. The high-pressure water jet does not damage the rebar during the breaking of the concrete, as the water jet acts on the pores and cracks of the concrete without affecting the hard rebar.
This technology is a modern breaking technology that can effectively break down concrete and protect the rebar from damage. It combines efficiency, safety, and environmental benefits, making it ideal for the maintenance and retrofitting of concrete structures.
▍ How it works
With the action of a high-pressure pump, the device is able to generate a powerful water jet of up to 100 to 280 MPa, which is sprayed directly onto the surface of the concrete.
Under the impact of this high-pressure water flow, an abnormal pressure forms in the pores of the concrete, and once this pressure exceeds the tensile limit that the concrete itself can withstand, the concrete will begin to disintegrate and crumble.
Concrete itself is a porous, heterogeneous material whose macrostructure is formed by the bonding of particles of various shapes and sizes. When we drill down to its microscopic level, we see that it is actually a three-phase (solid, liquid, and gaseous) porous structure. When a high-pressure stream of water is sprayed onto the surface of the concrete, it is able to create tension inside the concrete that exceeds the bending tensile strength of the material, causing the concrete to break. However, as a homogeneous and solid material, the surface of the rebar is not penetrated by water as a liquid, so the high-pressure water jet does not cause any damage to the rebar inside the concrete during the cleaning process.
▍The unique advantages of high-pressure water jet technology
◆ Precise selection: By adjusting the pressure and flow rate of the high-pressure water jet, the reinforced concrete can be accurately broken, and precise control can be achieved both in depth and width.
◆Multi-dimensional operation: Relying on the flexible setting of the actuator, the reinforced concrete can be broken at any angle and height, without the need to build an additional operating platform.
◆ Efficient operation: high-pressure water jet crushing concrete, compared with the traditional mechanical crushing method, greatly improves the operation efficiency.
◆ Non-destructive construction: there is no vibration in the whole construction process, there is no impact on the original structure and the components that need to be retained, and the steel bars are completely retained (rust is removed).
◆ High-quality effect: The broken interface presents a clean, hard concave and convex tooth, which is conducive to the tight adhesion between the old and new interfaces, without additional chiseling treatment, and the breaking depth can be accurately controlled within ±3mm.
◆ Environmentally friendly: using water as the working medium, it will not produce dust pollution, and it is more environmentally friendly.
◆ Safe and reliable: the use of mechanized, automatic operation, support long-distance remote control, greatly improve the safety of the operation.
▍ Comparison of other methods
◆ Manual rejection method
Basic tools such as sledgehammers and pickaxes are used to remove and crush the reinforced concrete of the wing plates, while retaining the reinforcement to facilitate the connection of the old and new bridges. Not only is this technique inefficient, but it also has little to no guarantee in terms of safety. It also produces strong noise and dust pollution, while consuming a lot of human resources. In addition, this method may cause tiny cracks in the retained structure and cause damage and destruction to the rebar.
◆ Mechanical demolition method
The high-pressure oil or gas provided by the pumping station is used to drive the cylinders to generate impact force, and the slab-like reinforced concrete is broken by mechanical equipment, while the steel bars are retained to realize the docking of the old and new bridges. Although this method is relatively efficient, it has significant safety hazards and significant noise and dust pollution. It can also cause large micro-cracks in the retained structure, causing severe damage, deformation, and even truncation of the rebar.
◆ Cutting and rebar implantation method
The connection between the old and new bridges is completed by first cutting part of the wing plate using a diamond disc saw or wire saw, and then drilling holes and using planting glue to secure the new reinforcement in place. This method has high efficiency and good safety, while at the same time relatively low noise and dust pollution, and does not cause any damage to the retained structure.
◆ High-pressure water jet method
A jet of high-pressure water generated by pressurization by a high-pressure pump is sprayed onto the surface of the concrete, creating an overpressure in the pores of the concrete, causing the concrete to break, while retaining the reinforcement to facilitate the connection of the old and new bridges.
This method is extremely efficient, can break any depth and thickness of concrete acording to the needs of the site, mechanized, automated remote control operation improves safety, and due to the use of water as the working medium, no dust contamination is generated, and no damage is caused to the retained structure and reinforcement.
