RELATIONSHIPS BETWEEN RHEOLOGICAL PROPERTIES AND PUMPING OF FRESH SELF-COMPACTING CONCRETE

摘要

In literature, the research topics on self-compacting concrete are numerous, almost covering the whole range from the raw materials to fully developed structures. In this research range, one particular item is still missing, namely the casting of SCC by means of pumping.Currently, not much is known on the relationship between the fresh concrete properties and the pumping process.This paper describes full scale pumping tests on self-compacting concrete. It contains two parts: the first part is dealing with the influence of the rheological properties of the concrete on the pumping process, showing that viscosity and shear thickening have a major importance.The second part contains the influence of pumping on the rheological properties of the concrete, where it is clearly shown that viscosity will decrease due to pumping. Structural breakdown and air content change the rheological properties of the SCC. If structural breakdown dominates the effects of the air content, the SCC will show a larger tendency to segregation. If the effects of the air content dominate, the yield stress of the SCC will increase,possibly leading to improper filling of the formwork.