Methods of Curing Concrete
Concrete curing is a process that does not allow the water or moisture from concrete to dry or evaporate before the concrete hardens. Concrete curing makes stronger concrete and it also reduces the permeability of concrete. There are various methods to cure concrete; of which the most common method is to sprinkle water on the concrete until it hardens.
Sprinkling of Water: This method involves the sprinkling of water on the surface of the concrete. This is an exceptional method of curing concrete though the requirement of water for this process is high. As Water forms, a layer over the concrete for a long period of time and this significantly reduces the evaporation of moisture from the concrete. When the temperature is between 50 and 75 degrees Fahrenheit there is less evaporation of moisture from the concrete ensuring that the moisture content remains high enough for the concrete to reach its maximum strength.
Shading or Covering of Concrete: Concrete is covered or shaded to avoid excess evaporation of moisture from the concrete. In this method, the concrete is covered with hessian, gunny bags or canvas. This technique is used in hot climates to protect the concrete from direct sunlight and wind. This technique could be used in cold climates as well to prevent concrete from freezing before is hardens.
Ponding Method: The Ponding Method is one of the most efficient methods of curing concrete. This method is usually adopted on flat or horizontal surfaces like floors and rooftops. Clay and sand are used to make divisions on the concrete after the concrete has been placed. Water is poured into these divisions and the clay and sand hold the water, thus creating a pond. Water is poured into these ponds twice of thrice a day depending on climatic conditions. The only drawbacks of this method are that huge amounts of water are used and if the clay and sands are not set well they may break and cause the water to flow out of the pond, and cleaning the clay and the sand after the concrete is cured could prove a tedious task.
Steam Curing: This method of curing allows the concrete to build up strength much faster than the other methods. The steam is maintained at a maximum temperature of 75oc. it is also the method adopted for precast concrete work. Hot water is also used to cure concrete. When hot water is used the temperature could be anywhere above 100oc . This method, however, has its drawbacks because the exact temperature has to be maintained over the entire piece of concrete. Non-uniformity in temperature would result in pieces of concrete not developing to its full strength. The rapid cooling and drying of the concrete also have to be avoided. Concrete cooling or dry8ing rapidly could lead to cracks.