Effect of chemical admixtures on rheological parameters and stability of fresh lightweight aggregate concrete

Abstract

This paper presents results of an experimental study on the effect of a superplasticiser and an air-entraining admixture (AEA) on the rheological behaviour of fresh lightweight aggregate concrete and the stability of the concrete under vibration. The results indicated that an increase in superplasticiser content in the concrete reduced the yield stress, but did not have a significant effect on the plastic viscosity. The increase in air content in the concrete by using AEA reduced the plastic viscosity. The yield stress, however, was reduced only when the AEA was first introduced. Further increase in the AEA content did not have a significant effect on the yield stress of the fresh concrete. When the concrete experienced vibration, the segregation resistance decreased with a decrease in both the yield stress and the plastic viscosity. However, the effect was more pronounced with the decrease in yield stress.