Concrete is one of the most durable materials you can use to build a home, but that doesn’t mean it is indestructible. It develops surface damages that could be fixed with patching and resurfacing. It could also develop structural cracks, or the surface might damage beyond repair. In such instances, the best option is to replace the concrete completely, hence the need for demolition. Here, we look at conditions that warrant for demolition and different demolition methods.
Conditions Where Demolition Is Necessary
Sunken Slabs: Where the concrete slab has sunk due to improperly prepared subgrade, it becomes necessary to demolish it and rebuild it. This usually happens where loose dirt is used as the subgrade or where it is not compacted correctly.
Deep Cracks: While surface cracks can be easily fixed, there are times when the damage is so deep that it reaches into the structure. Many factors can cause this, such as when loads that are heavier than concrete capacity is placed on it, erosion, improper subgrade, etc.
Frost Heave: Frost can also cause damages to concrete in a colder climate. What causes frost heave is the freezing of groundwater, which makes it expand, and therefore push up the soil or any surface.
New Construction: There are times when concrete structures are demolished to build a new property.
Remodeling: You might need to demolish part of the building if you are thinking of remodeling the building.
Faulty Concrete: Where there is a problem with a concrete batch’s quality, it is necessary to demolish the concrete and re-pour it.
Methods of Concrete Demolition
Pressure Bursting: this is one of the most effective ways of demolishing concrete. It is a controlled, quiet, and dust-free method which can be chemical or mechanical. The process involves drilling holes into concrete and applying lateral forces. In the chemical process, the expansive slurry is inserted into the concrete, causing it to split. For the chemical, a hydraulic pressure machine is used.
Hydraulic and Pneumatic Breakers: This is usually used for bridges decks, pavements, and foundation. There are breakers mounted on machines capable of demolition as much as 20,000 foot-pounds at the rate of 300-800 blows in a minute. Some of these breakers can even be operated using a remote from a different location through a telescoping boom. There are even those that are designed for use underwater.
Ball and Crane: This is the most common method and is performed with a crane and wrecking ball weighing 13,500 pounds. The ball could be swung or dropped on the structure to demolish, and it works very fast. However, you may have to cut the steel reinforcements using another method. It requires expert operators and generates a lot of noise, vibration, and dust.
Dismantling: You can cut through concrete with high-speed water jets, thermal lance, or saw. The cut concrete pieces are removed, making the structure to fall apart. There is little dust and noise when this is used.
Explosives: This is usually used in areas with a large volume of concrete; explosives can be used. They drill holes into the concrete, and explosives are inserted. It has to be controlled, or surrounding structures might be affected too.
Each method of concrete demolition has pros and cons. There are also areas where one method is better than another. All this must be considered during demolition to achieve the best results.