What does superplasticizer do to concrete?

Superplasticizers are used to increase the fluidity of concrete without adding excess water. These molecules physically separate the cement particles by opposing their attractive forces with steric and/or electrostatic forces, as explained in Chapter 11 (Gelardi and Flatt, 2016).

Is superplasticizer expensive?

Superplasticizers are more expensive than conventional water- reducing admixture s. The dosage re q u i rements va ry between 0.5 and 3 percent by weight of cement, depending on the type of admixture used.

What are the benefits of using superplasticizer additives in a concrete mix?

The basic advantages of superplasticizers include, (1) high workability of concrete, resulting in easy placement without reduction in cement content and strength; (2) high strength concrete with normal workability but lower water content; and (3) a concrete mix with less cement but normal strength and workability.

Does superplasticizer increase slump?

Superplasticizers, when added to fresh concrete, cause large increases in its slump. However, this increase in slump is not sustained over long periods and within 60 minutes or so the concrete reverts to its original slump.

How are superplasticizers used in the construction of concrete?

Superplasticizers (SP’s), also known as high range water reducers, are additives used in making high strength concrete. Plasticizers are chemical compounds that enable the production of concrete with approximately 15% less water content. Superplasticizers allow reduction in water content by 30% or more.

How long does it take for superplasticized concrete to set?

Concrete with only a superplasticizer might set in 4 hours. But concrete with both the water reducer and superplasticizer might take 6 hours or more to set. What type of cement was used? For a water treatment plant, especially with the thick section, Type II or Type V cement may have been used. These types set slower than Type I or III cements.

What are the advantages and disadvantages of a superplasticizer?

Plasticizers are chemical compounds that enable the production of concrete with approximately 15% less water content. Superplasticizers allow a 30% or more reduction in water content.

What causes the delayed setting of superplasticized concrete?

Delayed Setting of Superplasticized Concrete. Excessive bleeding may have slowed setting. Part of the stiffening process that permits finishing is caused by drying, part by cement hydration. Because the section was so thick and there was a vapor barrier beneath it, there was probably a lot of bleed water on the surface that prevented any drying.