Water-reducing High Range Concrete Admixtures (Superplasticizers)

This Common Product describes water-reducing high range concrete admixtures, which are designated as Type F under ASTM C494/C494M. These admixtures are also known as superplasticizers and are the most commonly used concrete admixtures. These admixtures may also be classified as Type A, water-reducing admixtures. Superplasticizers reduce the amount of water required to cure concrete and also facilitate the placing and compacting of concrete by increasing its slump (meaning it is more fluid and workable). Superplasticizers are used in both normal and high performance Portland cement concretes. When these admixtures are mixed with Portland cement and water, agglomerated cement particles break down. The superplasticizers adsorb onto the cement particles and repel each other preventing re-agglomeration. This effectively lowers the yield stress and viscosity of the cement mixture. Since these admixtures tend to retard the rate of hydration, accelerators may be added separately to decrease the setting time of the concrete. Polycarboxylate superplasticizers (PCEs) were found to be most common among the sources referenced. PCEs yield the greatest dispersion strength among the most common types of superplasticizers and can reduce water content in concrete by up to 40%. Because PCEs can influence the air-entrainment of the concrete to a higher degree than other types of superplasticizers, a defoamer may be added. Other common types of superplasticizers include sulfonated naphthalene formaldehyde condensates (polynaphthelene sulfonates, PNS), sulfonated melamine formaldehyde condensates (polymelamine sulfonate, PMS), and lignosulfonates (LS). For details on additional chemicals identified in this research see the All Contents tab.