What is the specific setting time

What are specific additives?

COMMON CONCRETE ADMIXTURES AND THEIR BENEFITS

Admixtures are used in concrete for a number of reasons. Because admixtures change the chemical composition of concrete, contractors can pour the concrete flexibly and machinably to meet project specifications, meet strength requirements, or work in adverse weather conditions.

WATER REDUCING ADMIXTURES (WRA)

Water-reducing admixtures are used for two different reasons. (1) Lowering the water content in fresh concrete and increasing its strength. (The more water is added to the concrete, the weaker the strength of the concrete once it is hardened.) (2) To get a higher sink rate without adding additional water and improve workability.

FLOOD REDUCER (SUPERPLASTICIZER)

Plasticizers are used to increase the strength and permeability of concrete by reducing the water content in the mix. Plasticizers are useful in high strength mixes as they improve the workability of the concrete. This admixture also increases the absorbency without adding water.

AIR TRAINING ADMIXTURES

With air-entraining admixtures, small, even air bubbles are created. A major benefit of using air entraining agents is that they increase the durability of the hardened concrete, especially in climates that are exposed to freezing and thawing cycles. The entrainment of air also increases the workability of the concrete.

RETARDERS

Retarding additives are used when the setting time of the concrete needs to be slowed down. Retarders are often used in hot weather to counteract the rapid setting caused by high temperatures. It allows more time for placement and post-processing.

ACCELERATOR

When you need concrete to set faster, accelerators are used. By shortening the setting time, the hardening process can start earlier and the concrete is ready sooner.

This is especially helpful in the winter months as lower temperatures can slow the setting time. Whenever the curing process needs to be sped up, contractors can add accelerators to the mix, and not just in cold weather.

OTHER TYPES OF CONCRETE ADDITIVES

There are many types of admixtures on the market that can modify and set concrete. For example, admixtures can be used to produce the following results:

Protection against freeze-thaw cycles Improves shelf life

Middle class water reducer

High strength concrete

Corrosion protection

Strength increase

Crack control (shrinkage reduction)

Fluidity

Stop improvement

Fly ash (concrete stronger, more durable and easier to work with)

Silica Fume (early strength and reduced permeability)

Produce a liquid backfill that flows easily and aligns itself