Rheology Of Self-compacting Concrete And It’s Influence On Distinct-layer Casting

Self-compacting concrete(SCC) is high fluidity concrete which can be placedwithout vibration, because of this feature the rheology and thixotropy of SCC play aimportant role on SCC’ construction process. A suitable rheology and thixotropymake SCC better, SCC with an unsuitable rheology and thixotropy will deterioratewhen mixing,transport,pouring, and decrease the quality of construction.This paper studies some factors of the rheology and thixotropy of SCC byConcrete Rheometer. Fly ash and ground slag can lower the shear stress, plasticviscosity, static yield stress, the dynamic yield stress, and reduce the change withtime. High w/c make fresh SCC lower shear stress and plastic viscosity and delaythe change time. A high temperature makes fresh SCC a lower shear stress andplastic viscosity, but increases SCC’ change over time. Fly ash, ground slag andretarder can weaken the change over time of SCC.When SCC is distinct-layer casting, there is a short time to rest berore thesecond layer of concrete is cast above it, the plastic viscosity and static yield stressof the first layer of concrete may influence the quality of the bond between the twolayers. The lower plastic viscosity and static yield stress, the higher quality. Whentthe age of concrete is change, the influence of distinct-layer casting is different. Flyash, ground slag or high w/c will lower the quality of SCC casting one step, but isbeneficial for distinct-layer casting SCC when there is a longer rest time.