What is curing of concrete?
The process of proper hydration of concrete or spreading water on the surface of the concrete to maintain adequate moisture and temperature is known as curing. Proper curing of concrete makes the concrete hard, and durable and helps to achieve better strength.
How does curing affect the strength of concrete?
Whenever water is mixed with cement, a chemical reaction occurs between different cementitious materials in concrete. This process is known as hydration.
Hydration helps the concrete o get strength and be durable. Hydration in concrete makes concrete impermeable. If we do not cure concrete properly then concrete does not have a way of hydration which make concrete weak.
Why curing of concrete is important?
The main purposes of curing concrete are given below,
1) It enhances the strength of concrete by allowing hydration between cementitious materials.
2) It Reduces the chance of cracking in concrete. Curing prevents from rapid drying of concrete which leads to shrinkage in concrete. and Shrinkage leads o the cracking of concrete.
3) Curing improves the durability of concrete by increasing the desired strength of concrete. It improves the permeability of concrete and prevents external environmental factors.
4) It increases the uniformity of concrete by allowing chemical reactions due to hydration and makes the structure hard uniformly.
5) Curing helps to achieve desired finish by letting concrete to set properly.
How much water required for curing of concrete?
The amount of curing required in concrete depends on different factors like environmental conditions, water-cement ratio, the thickness of the structure, etc.
According to IS Code, the minimum curing time for concrete in the winter season should not be less than 7 days, and 14 days for the summer season.
What are the methods of curing concrete?
There are different methods of curing but, here I have discussed 5 important methods of curing.
a) Ponding / Water Curing: Ponding is the most effective method of curing concrete. Ponding is done by spraying water directly on concrete or by surrounding water on the concrete.
b) Membrane Curing: Membrane curing is done generally in vertical members like columns and walls. Jute bags or plastic bags are wetted in water and kept on the topmost part of concrete to cure from time to time
c) Chemical Curing: Chemical methods of curing are done where there is a shortage of water. Some special types of chemicals are used on concrete to prevent the water within the concrete from evaporating. In this method, hydration is done with the help of water within the concrete.
d) Steam Curing: Steam curing is generally done in precast concrete members. Hot steam is inserted within the concrete to implement a rapid curing process.
e) Insulation Curing: Insulating curing is generally used in cold weather where concrete does not need more water for complete hydration. In this method, insulation materials like plastics membrane, straws, etc are spread over the concrete to maintain the temperature within the concrete.
When to Start Curing of Concrete?
The starting time of curing in concrete depends on different factors like environmental factors, sunny weather, wind, etc. But, generally curing in concrete can be done after a minimum of 6 hours and within 24 hours.
Curing should be started just after the concrete begins to dry. If we make it late in curing, then there will be shrinkage and cracks in the concrete.