Concrete curing is a chemical reaction of concrete ingredients. Concrete curing is the process of maintaining moisture inside the concrete under a specific environmental condition for promoting hydration.Concrete curing is done to increase concrete strength and stability. Concrete curing methods are decided according to the working procedure and weather condition.
Curing by wet covering is mostly observed on the construction site wherein different types of fabrics saturated with water are used. This is also known as moist curing concrete. These methods are used on both vertical and horizontal concrete surfaces.
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In moist curing concrete method, water absorbent fabrics are used to maintain moisture on the concrete surface by completely covering the surface immediately after the concrete has hardened sufficiently.They must be continuously kept wet to prevent the fabric from absorbing water from the body of concrete, due to capillary action.
The Different Types of Fabrics or Materials Used are:
- Burlap for concrete curing
- Cotton mat
- Rugs
- Hessian cloth
- Jute fabric or Jute bag
- Other moisture retaining fabrics/ materials such as clay, sawdust or hay
The Precautions to be Taken in Moist Curing Concrete Process are as follows:
- To prevent surface damage, concrete should be covered with the fabric as soon as it has hardened.
- The entire surface including the edges and joints of the slab should be kept covered so that these parts are not left inadequately cured.
- The fabric retains water for a great period of time. Therefore, the fabric must always be kept wet or moist so that concrete surface is in contact with water throughout the curing period of concrete.
- The wet burlap for concrete curing used should be free from sizing or any substance that is harmful to concrete and would cause discolouration.
- If burlap for concrete curing is used, it should be first rinsed in water to remove soluble substances and to make it more absorbent.
- A layer of earth, sand, sawdust (50 mm thick) or hay (150 mm thick )can be used as an effective medium to retain moisture for a longer period on flat surfaces rather than keeping it totally exposed. It is necessary to keep these materials continuously wet so as to prevent them from blowing away or even they absorbing water from concrete by capillary action or reverse the process.