When it comes to concrete restoration, proper attention to surface preparation is essential for a durable repair. Because there are so many steps in the removal and restoration process, it’s important to follow specific guidelines to ensure your project is successful. In this blog, we’ll discuss the guidelines and methods for concrete restoration and cooling tower repairs, such as:

• Cutting methods

• Impacting methods

• Milling methods

• Surface cleaning methods

Cutting Methods

Cutting methods are used for full depth repairs and use full-depth perimeter cuts to disjoin deteriorated concrete for removal. Some cutting methods include:

• Saw

  • These saws are typically made of diamond or carbide and are available in multiple sizes, ranging from handheld to very large.

• High pressure water jet

  • This tool uses a small jet of water driven at high velocities, commonly producing pressures of 10,000 - 45,000 psi

Impacting Methods

Impacting methods are the most commonly used concrete removal techniques. They generally consist of the repeated striking of a concrete surface with a tool or large mass to fracture and spall the concrete. However, the use of impacting methods in partial-depth removal may produce micro-cracking in the surface of the remaining concrete, which can result in a weakened plane below the bond line. Some impacting methods include:

• Handheld breakers

  • These handheld hammers are probably the best known of all concrete removal devices. They’re available in different sizes and energy levels, so you can get the right tool for the job, whether it be total or partial removal.

  • Using your handheld breaker, strike the deteriorated or damaged concrete, working from inside to outside. The force of this method should remove all damaged concrete until only the sound concrete remains.

• Scabblers

  • Scabblers are best known for their ability to remove shallow depths of concrete from the surface using compressed air. Scabbler heads come in various sizes and shapes — the size of the equipment usually depends on the number of cylinders it has.

Milling Methods

Milling methods are commonly employed to remove a specified amount of concrete from large areas of horizontal and vertical surfaces. The removal depth may vary from 1/8-inch (3 mm) to several inches. Milling operations usually leave a sound surface free of micro-cracks. Some milling methods include:

• Scarifier

  • A scarifier is a concrete cutting tool that uses the rotary action and mass of its cutter bits to cut into the surfaces. The scarifier is a very effective tool for removing deteriorated or damaged concrete on vertical and horizontal surfaces and comes in a variety of sizes.

  • Other advantages of this method include well-defined limits of concrete removal, relatively small amounts of debris, and simplicity of operation.

• Hydrodemolition

  • High-pressure water jetting (hydrodemolition) may be used as a primary means for concrete removal when you want to preserve and clean the steel reinforcement for reuse. This method disintegrates concrete into gravel-sized pieces.

  • This method has the advantage of removing concrete without leaving micro-fractures in the existing surface.

  • It’s important not to “punch” through thin slabs or walls if unsound concrete exists in an area that needs repair.

Surface Cleaning Methods

​​Some concrete removal methods can also be used for surface cleaning. The best way to restore the surface of your concrete is by using different abrading methods that easily remove thin layers of concrete. These methods include:

• Abrasive blasting

  • This process uses sand, metallic sand, or granulated slag to remove surface layers of concrete.

• Shotblasting

  • Shotblasting equipment cleans or removes surface concrete by projecting metal shot at a high velocity.

• High pressure water blasting

  • This cleaning method uses a high-pressure stream of water with an abrasive, such as aluminum oxide or garnet, introduced into the stream.

How Can CTI Assist With Your Cooling Tower Needs?

Cooling Technology Institute has published a plethora of papers about various cooling topics. CTI is also an advocate in promoting the use of environmentally responsible Evaporative Heat Transfer Systems (EHTS), cooling towers, and cooling technology for the benefit of the public. Additionally, CTI is an independent, third-party thermal performance testing to help participating manufacturers and owners/operators achieve the best performance from their cooling towers. Visit our website today for more information on cooling technologies!