Superplasticized or "flowing" concrete represents a fast growing proportion of ready mixed concrete deliveries in Western Europe, most notably in Germany and Belgium. The idea of flowing concrete was first conceived in 1968 when the advantages of a new class of admixture called superplasticizers became apparent. Superplasticizers are chemically quite different from the older types of water-reducing admixtures. They are basically the condensation products of melamine resins or napthalenes. These admixtures can either produce very fluid concrete without increasing the water-cement ratio or else function as super water-reducers. Typically these admixtures have little or no effect on the setting time and, at high fluidity, concrete containing superplasticizers shows a remarkable lack of segregation and bleeding.
Flowing concrete has also been widely used by many precasting companies throughout the world chiefly to ensure complete penetration of the concrete into very heavily reinforced forms. Such mixes facilitated precasting of the structural elements for the Montreal Olympic Stadium which required very high early strength for demolding and yet high fluidity to achieve complete consolidation among the rebars and post-tensioning ducts.
This article discusses advantages, properties, applications, and placing of flowing concrete mixtures.