Workability of air-entrained lightweight concrete from rheology perspective

Abstract

Effects of air entrainment on rheological parameters and slump of fresh lightweight aggregate concrete were studied. Results show that yield stress and plastic viscosity of air-entrained concrete were lower than those of non-air-entrained concrete with similar superplasticiser dosage. As the entrained-air content increased, the plastic viscosity decreased whereas the yield stress remained relatively unchanged. The slump of the air-entrained concrete was significantly higher than the non-air-entrained concrete. At similar yield stress, the slump of the air-entrained concrete was higher owing to its lower plastic viscosity by air entrainment. At similar slump, the air-entrained concrete had higher yield stress and lower plastic viscosity, implying that higher shear stress is needed to initiate flow but flow resistance would be lower.