Importance of Curing of fresh Concrete

Curing plays an important role in strength development and durability of concrete. Curing takes place immediately after concrete placing and finishing, and involves maintenance of desired moisture and temperature conditions, both at depth and near the surface, for extended periods of time. Curing is the process of controlling moisture loss from concrete that has already been placed. Curing ensures hydration of the cement, which in turn enhances it, s strength and durability. Curing takes place immediately after placing the concrete and deals with maintenance of the desired temperature and moisture for extended periods of time. Properly cured concrete has an adequate amount of moisture for continued hydration and development of strength, volume stability, resistance to freezing and thawing, and abrasion and scaling resistance.

The length of adequate curing time is dependent on the following factors:

• Mixture proportions
• Specified strength
• Size and shape of the concrete member
• Ambient weather conditions

Curing has a strong influence on all properties of concrete and therefore it should not be taken lightly. Properly cured concrete has a better surface hardness and can better withstand surface wear and abrasion. Curing also makes concrete more impermeable, which prevents moisture and water-borne chemicals from entering into the concrete, thereby increasing durability and service life. Proper curing helps to prevent grazing, dusting, surface disintegration and scaling. Adequate curing reduces shrinkage, gives better resistance to wear and improves long-term appearance. Without proper curing, the chemical process of hydration is not complete. You will never be able to get the designed strength of concrete and please note that this is a loss of strength for a lifetime and there is no easy alternative to strengthen such poorly cured weak concrete. So always be careful and cure with care. 

Methods of Curing and its Comparison

Concrete Curing Methods	Advantages	Disadvantages
Sprinkling with Water or Covering with Burlap	Excellent results if kept constantly wet	Likelihood of drying between sprinklings; difficult on vertical walls
Straw	Insulator in winter	Can dry out, blow away, or burn
Moist Earth	Cheap but messy	Stains concrete; can dry out; removal problem
Pending on Flat Surfaces	Excellent results, maintains uniform temperature	Requires considerable labor; un- desirable in freezing weather
Curing Compounds	Easy to apply and inexpensive	Sprayer needed; inadequate coverage allows drying out; film can be broken or tracked off before curing is completed; unless pigmented, can allow concrete to get too hot
Waterproof Paper	Excellent protection, prevents	Heavy cost can be excessive; must drying be kept in rolls; storage and handling problem
Plastic Film	Absolutely watertight, excellent protection. Light and easy to handle	Should be pigmented for heat protection; requires reasonable care and tears must be patched; must be weighed down to prevent blowing away