There are several conditions that call for concrete removal and replacement. Often, fixing it with a decorative topping or patching the concrete before resurfacing is considered a short-term fix. However, it will soon display the characteristics of damaged concrete that you tried to repair. Under such conditions, concrete demolition and replacement is mostly recommended to ensure that repair work is done from scratch and sturdy enough to last for long.
So, under what circumstances is concrete removal recommended? Typically, it is where there are widespread and deep cracks or the concrete slabs have sunk that you require prompt concrete removal and replacement.
At the same time, concrete slabs that have too much pitting and spalling on the surface or which shows the signs of frost heave are the ones where replacing the concrete can prove to be more economical and reliable than merely resurfacing the entire concrete.
Different Methods of Concrete Removal
Several methods are used in concrete demolition, which is the first and most important step in replacing the concrete in case of excessive damage and building it all over again.
1. Pneumatic and Hydraulic Breakers
Such type of boom mounted or handheld machine tools are frequently used for concrete removal, which involves pavements, bridge decks, and foundations. The level of work achieved by this method typically depends on the strength of the concrete, hammer size of the breakers, working conditions, and amount of steel reinforcing used in the concrete.
Machine-mounted pneumatic and hydraulic breakers can deliver from 100 to 20, 000 foot pounds at just 300 to 800 blows per minute. To ensure that the maximum amount of work is accomplished in a convenient and hassle-free manner, the breakers may also use remote control operation, telescoping boom for maneuverability and reach, and underwater concrete demolition capabilities.
2. Pressure Bursting
Where dust-free, controlled and relatively quiet concrete removal is desired, pressure bursting – mechanical and chemical – is the ultimate choice. Under mechanical pressure bursting technique, the concrete is spilt using a high-power and efficient splitting machine that operates on hydraulic pressure, powered by a motor. In case of chemical pressure bursting, expansive slurry is inserted into a particular pattern of boreholes.
The demolished concrete is then removed easily by hand or crane. Such methods ensure breaking up concrete structures with minimum dust and noise. Under both the methods, holes aredrilled into the structure and lateral force is applied against the same to split the concrete.
In this process, concrete elements are cut into smaller pieces using a saw, thermic lance or water-jetting technique, and then the broken pieces are removed by crane. Such a method ensures minimum impact on surrounding structures, emitting lesser dust and noise.
This is a fantastic technique for demolishing a certain portion of the structure, say slabs or walls.
Water-jetting can be used in cutting both contours and straight line and requires usingthe water catching system and abrasive during the cutting process. On the other hand, thermic lance works especially well on steel reinforcing and eliminates dust and vibration.
4. Ball and Crane Method
This is one of the most commonly used techniques in demolishing a building. Here, a ball, weighing up to 13,500 pounds and a crane is used in demolishing masonry and concrete structures. The ball is either swung or dropped onto the structure that needs to be demolished.
However, the process is not suitable for all types of applications and may create a lot of noise, dust and vibration. Only experienced and highly skilled crane operators should perform the concrete demolition method.
When large volumes of concrete have to be removed, explosives are inserted into a series of pre-determined boreholes, which blast and cause the structure to break into smaller pieces. The method is indeed flexible and versatile pertaining to work output.
However, air blast and vibration may cause damage to the surrounding structure and it is important to take highest standards of safety measures during the process.