What is Curing

1
What is Curing?
With thanks to CIA and Ramon Hodge
2
What is Curing?

• Water Curing
• Maintaining sufficient water within the concrete
  structure to ensure
• Cement is hydrated
• Strength is developed

3
What happens if you dont water cure concrete?

• May develop plastic shrinkage cracking in drying
  conditions
• Lowers compressive strength
• Lowers tensile strength and increases chance of
  drying shrinkage cracking

4
How to water cure concrete

• Spray aliphatic alcohol on plastic concrete
• Ponding
• Leave forms on
• Cover with plastic
• Cover with hessian, sand and keep moist
• Spray with curing compound

5
Leave Forms On
6
Cover with Plastic
7
Apply Curing Compound
8
Cover with Plastic
9

Cold Weather

• Hardening of concrete is a chemical process and
  as in many chemical reactions, is temperature
  dependent
• The lower the temperature, the slower the process
  of cement hydration
• The speed of hydration process is very much
  dependent on
• Temperature
• Type of Cement
• WaterCement ratio
• Other chemicals in the concrete

10

Cold Weather

• Effect on fresh concrete
• Longer setting time
• Delayed finishing
• Longer bleeding time
• Effect on hardened concrete
• Slower strength gain
• Delayed removal of formwork

11
Precautions for Hot Weather Concreting

• Plan ahead and prepare for each job
• Have adequate labour so that concrete can be
  properly placed avoiding delays
• Dont order or try to place more ready-mixed
  concrete than you can reasonably expect to finish

• Moisten sub grade, reinforcing steel and wooded
  forms before placing concrete (subgrade should be
  damp not muddy)