Concrete is known as the most long-lasting building materials available. Various factors, such as temperature changes or structural flaws, cause cracks in the placed concrete mix. It is impractical to expect crack-free and curl-free floors, even with the best design. Some amount of cracking and curling is common in construction projects. Cracks rarely are testament to the adequacy of the floor design or the quality of construction.
Plastic concrete refers to concrete that is still fresh. Even though the components of this concrete are thoroughly mixed when it is in a plastic condition, it is still unable to provide strength. A fresh concrete mix is a newly mixed substance that is moulded into any shape. Any of these two states lead to cracks in concrete.
However, not all cracks are the same. Detecting the type of crack will assist you in repairing it correctly. RMS Concrete will help you explore some common types of substantial damage with this blog.
Why Does Crack Occur On Concrete?
Silica fumes produce a very cohesive and tacky concrete with a low bleeding capacity. However, silica fume concrete is susceptible to plastic shrinkage cracking in hot, windy weather with little or no water spillage on the surface. Clouding up air over concrete and installing wind curtains reduces the risk of cracking due to plastic shrinkage.
Cracking arises from various factors, such as
- Thermal contraction
- Stress on shortening
- Subsidence of the support
- Applied loads
- Drying shrinkage
Types Of Concrete Cracks
Plastic Shrinkage Concrete Cracks
It occurs when there is rapid moisture loss due to air and concrete temperatures, humidity, and wind velocity at the surface of the concrete. These factors cause high surface evaporation rates in either hot or cold weather. When moisture evaporates from the surface of freshly placed concrete faster than it is supposed to, the surface concrete shrinks.
It requires control measures to reduce the shrinkage between the surface and other concrete portions. A fog nozzle will saturate the air above the surface, and the use of plastic sheeting to cover the surface between finishing operations.
Plastic Settlement Cracks
Plastic settling cracks are formed in freshly placed concrete. Plastic settlement cracks appear on the surface before the concrete-mix has hardened or when there is a lot of bleeding. Fresh concrete settles when it is poured into deep formwork like a wall. Steel bars obstruct the settlement and cause short horizontal fractures. Moreover, the impediments damage the back of the concrete above them.
Concrete Cracks Due To Premature Drying
Cracks form when a concrete slab loses moisture quickly. Cracks emerge when the top layer of the slab naturally loses its humidity, and crusting fractures appear when the top layer is cured; both are unpleasant, but they are harmless to the slab’s structural integrity.
Expansion Concrete Cracks
Concrete slabs tend to expand outwards when they are exposed to heat. Slabs will crack when they do not get enough room to grow. Concrete expands and pushes against anything when it comes into contact with a brick wall. The increasing force causes concrete to crack.
Expansion joints separate static surfaces; They are formed of a compressible material such as asphalt, rubber, or wood, and they act as shock absorbers to ease the stress caused by the expansion.
Heaving Concrete Cracks
Heaving cracks caused by varying temperatures. Exposure to freezing temperatures causes the slab to condensate, resulting in heaving cracks. The slab expands back to the original shape when the temperature becomes normal; heaving cracks typically happen due to a shift in temperature.
Cracks Due To Chemical Reaction
Harmful chemical reactions are caused by concrete cracking. These reactions can be caused by the materials used to construct the concrete-mix. Interactions between active silica aggregate and alkalis from cement hydration, admixtures or external sources may crack concrete over the years.
Concrete is a robust building material, but it has certain limitations. Putting too much weight on top of concrete will result in a crack. Excessive load on the ground beneath the slab is more likely to develop. However, overloading of the concrete slab itself is uncommon in residential construction.
Heavy rain or snowmelt puts weight on the concrete, and when the ground below is soft, it can push the concrete down, resulting in cracks. It occurs more on driveways where large vehicles or dumpsters are parked.
Error in Designing and Detailing
Poorly installed slabs, inappropriate reinforcement, restraint of members susceptible to volume changes due to moisture or temperature fluctuations, and lack of adequate contraction joints result in various movements within the structure that can lead to unacceptable cracking.
Concrete material provided by RMS Concrete will considerably scale back or eliminate the formation of cracks and deterioration related to thawing. Our concrete-mix specialists can guide you to repair the cracks in concrete for all your residential and commercial projects. Call our team at +44 808 274 0949 or visit us online to learn more about our services. You can also read our blog to prevent cracks in your ready-mix concrete.