Superplasticizer (high-range water reducer)
A powerful water-reducing admixture that turns a stiff mix into a flowing one without adding water. It is what makes pumped and self-consolidating concrete possible.
What does superplasticizer (high-range water reducer) mean?
Superplasticizers can dramatically increase slump for a limited period before the concrete returns toward its original consistency, which means placement has to be scheduled around the dose. They allow very low water-cement ratios to remain placeable, which is the foundation of high-strength and high-durability concrete. Overdosing can cause segregation, excessive bleeding, or retarded set.
In practice
On a pump job, the truck often arrives at low slump and is dosed on site so the mix stays flowable exactly through the placement window.