smf superplasticizer is used in construction and industrial products to reduce water content, while increasing the fluidity and workability of the mix. It is widely used as a water reducer in concretes, mortars and plasters to increase their durability and resistance to aggressive environments.
It is a solid concentrate with a low release of formaldehyde. It can be formulated as a primary or secondary component in admixtures.
SMF Powder is mainly used as a superplasticizer or high range water reducer in the formulation of drymix mortars, cement and gypsum compounds. It is also used in various emulsions.
The chemistry of SMF is similar to that of SNF but has a different steric stabilization mechanism.
In SNF the molecule all carry -SO3Na groups, which dissociate into -SO3- and Na+ in water. Part of the negative charge on the -SO3- is used to attach the admixture to the cement but the rest orientates out from the cement grain and repels the positive charges on the admixture adsorbed onto an adjacent cement grain, keeping the two cement grains apart (see Figure 4.10).
Unlike SNF, PCE superplasticizers do not use -SO3Na groups in the molecule but instead have long polyether chains. The steric hindrance prevents the polyether chains from entangling with each other, and therefore keeps the two cement grains separate.
Several studies have shown that steric stabilization prevents the PCE superplasticizer from losing its effectiveness, even when it is mixed in alkaline solution (see Chapter 10). Furthermore, it is effective to break fly ash particle agglomeration and avoid the loss of workability, as explained in Chapter 6.