Self-Consolidating Concrete (SCC) was developed in Japan in the 1980s and came into widespread use in the United States in the 1990s. SCC concrete is a free-flowing mix that requires up to 40% less water, yet flows freely around reinforcement so that it does not have to be vibrated into place, saving energy. Because of its thixotropy, the concrete traps less air, resulting in a smoother form surface that is relatively free of bug holes.
Polycarboxylate admixtures in SCC achieve this performance through:
Electrostatic dispersion, a state created by the admixture which allows it to attach to the cement grains electrically and repel other admixture molecules and cement grains
A much larger than normal molecular weight (size)
Steric Hindrance, a state created by the massive size of the admix molecules attached to the cement grains that prevents contact of the grains and promotes fluidity of the cement paste. It also takes longer for the admixture to be overtaken by the gel formation around the cement grain caused by the hydration reaction