Plastic shrinkage cracking refers to the cracks formed when concrete has not yet set. It occurs when the concrete is in the form of plastic only. The main cause behind crack formation is the rapid drying process. Cracks can be seen the next day after the finishing operations. Plastic shrinkage cracks can form randomly or can be roughly parallel to each other. Concrete Brisbane gets weak due to these cracks and therefore expand.
What Causes Plastic Shrinkage Cracks?
The basic reason behind the occurrence of cracks is the higher rate of evaporation of moisture from the surface. When the evaporation rate exceeds the moisture supplied to the concrete, cracks are formed. The concrete surface dries out because of the lack of moisture on the surface and hence it cracks.
Water is lost in the following two ways:
- Drying from the top: During the placement process, moisture seems to evaporate from the top surface of the concrete, which is also known as bleeding.
- Drying from the base: Water can get absorbed in the ground below the concrete slab. This increases the risk of cracking and also the settlement of concrete and mesh reinforcement Brisbane.
There are various environmental factors that affect the rate of evaporation from the surface of concrete, such as wind speed, temperature, and humidity. A combination of all these factors leads to cracking even in cold weather conditions. Also, the concrete mixtures which have a reduced rate of bleeding are prone to plastic shrinkage cracking. Any factor that contributes to a delay in the setting process, leads to cracking.
How to Control Plastic Shrinkage Cracking?
Mentioned below are the tips that will help you in minimising plastic shrinkage cracking in your concrete:
- Dampen the surface of concrete frequently.
- During hot weather, mix water with crushed ice or use chilled water.
- Use windbreaks to reduce the velocity of wind that is coming on the surface of the concrete.
- Use product substitutes that reduce the rate of evaporation from the surface.
- Start the curing regime immediately after finishing.
- Use synthetic or steel fibers to prevent cracking.
- Accelerate the setting time of concrete.
- Use fog sprays in dry periods to discharge a fine mist into the air. Fog sprays reduce the rate of evaporation from the surface of mini concrete Brisbane and should be used until curing is applied to the concrete.
- Cover the concrete with moisture-retaining coverings like polyethylene or building paper sheets.
Reocrete is the leading supplier of concrete and steel reinforcing mesh in Brisbane. We deliver the right grade and consistency of concrete to your worksite at the exact time and day you need. We understand how much of a difference just a 30-minute delay in the compaction of concrete can cause. So, we practice what we preach and deliver exactly what you need!