Effects of Inadequate Concrete Curing

According to the American Concrete Institute (ACI) Committee 308-92, “Curing is the maintaining of a satisfactory moisture content and temperature in concrete during its early stages so that the desired properties may develop”.

• Purpose: preventing/reducing evaporation of water from the concrete surface in its early life
• Before setting
• After setting (typically for 7 days)

Curing Methods

1. Water – simplest
2. Wet Hessian
3. Plastic sheeting
4. Curing Compounds

Effects of Inadequate Curing

 Plastic shrinkage: occurs when the rate of evaporation exceeds the rate of bleed – causes loss of volume in concrete

the surface creates stress and cracks.

•  Drying shrinkage: occurs on the surface of slabs or struck faces after removing shutters
• Increased permeability: occurs when hydration cannot be completed, i.e. until the continuous porosity in the concrete is not completely blocked
• Reduced strength & abrasion resistance: incomplete hydration can cause the concrete to not reach its full strength; a dried out top surface can become very dusty & will have a poor abrasion resistance
• Reinforcement corrosion: high permeability of concrete surface allows aggressive materials to enter easily. Carbon dioxide will rapidly penetrate & neutralize the concretes natural high pH, leading to the depassivation of the steel and susceptibility to corrosion. Cracking enhances this process.
• Surface damage: lack of strength & wear resistance can easily lead to rapid surface damage.

Curing Compound Application

• Must be applied as soon as possible after the concrete has been poured into place.
• Shall be applied after the bleeding on the surface of the concrete has disappeared.
• Must be evenly applied to the whole surface of the concrete by using a suitable spray application.
• Should not be disturbed until a stable film has formed and the concrete has stiffened.

For more information, refer to the material TDS and method statement of the curing compounds