Chemical Admixtures for Concrete
Accelerators: Definition
• An accelerating admixture is a material that is added to concrete for reducing the time of setting and accelerating early strength development.
Accelerators: Classification
• Accelerating admixtures,
• Water-reducing and accelerating admixtures
Usage
• Accelerating admixtures are used in cold water concreting operations and also are components of antifreezing admixtures and shotcreting mixes.
• In cold weather concreting, there are other alternatives;
– use of rapid-hardening cement,
– use of higher than normal amount of ordinary portland cement,
– warming of the concrete ingredients.
Advantages of Using Accelerators
– efficient start and finishing operations,
– reducing the period of curing and protection,
– earlier removal of forms so that the construction is ready for early service,
– plugging of leaks,
– quick setting when used in shotcreting operations.
Influence of calcium formate on the compressive strength of concrete
