Non-Structural Concrete Crack Reduction
Although steel wire meshes are conventionally used for concrete crack control, there are many limitations and concerns associated with them such as constraints of placing them in thin concrete sections, extensive time of handling and construction, as well as the major concern of steel corrosion and subsequent cracking, especially in coastal and hot climate conditions.
G.Tex Netting Grids erase all these concerns. These products have been used widely since 1997 in walkways, canals lining, slope protections and proved its excellent effectiveness in controlling shrinkage cracks during the early life of concrete surfaces. The main purpose of using these products is to achieve a good durable concrete surface that will not require regular maintenance.
A recent study at a third-party laboratory comparing the application of G.Tex products versus traditional steel mesh showed that G.Tex products were more effective than steel. The conclusions included the following:
Plastic Shrinkage: Such cracking can be very deep and ranging in width from 0.1mm to 3.0mm. As well, it can be of short length or as long as 1.0m. Once these cracks are developed, they are difficult to close permanently. Further, wind and sun aggravate the situation.
Drying Shrinkage: Withdrawal of water from concrete cured in unsaturated air causes drying shrinkage at the surface. In concrete sections, the loss of water with time depends on the size of the element. The magnitude of drying shrinkage is inversely proportional to the thickness of the concrete element. Cracking at the surface also increases the rate of loss of water, which makes it even more necessary to prevent these cracks.
Differential Shrinkage: Moisture loss mainly takes place at the surface, which leads to a moisture gradient being established in the concrete sections, and thus leading to differential shrinkage. This induces strains that are tensile at the surface and compressive at the core.
Curing of Concrete: During the curing period of concrete (first 28 days), cracking occurs on the concrete surface.
In addition to all the causes of surface cracking previously mentioned, there is an additional cause that was found to be a problem. In reinforced concrete elements, cracking at the concrete surface can develop due to the differential settlement of the fresh concrete caused by the obstruction of the steel reinforced to the settlement of the concrete.