LAUSR

Abstract This research mainly studies the effect of bubble feature parameters (bubble size, specific area, spacing factor) on rheological properties of fresh concrete, in order to provide new methods for the development of air-entrained technology. Based on the great linear correlation of air content and similar bubble (pore) size distribution of fresh concrete and hardened concrete at 3d, the bubble size distribution of fresh concrete was approximately characterized by pore size distribution of hardened concrete. Yield stress and plastic viscosity of sieved mortar was measured by NXS-11B rotary viscometer, the mechanism of bubble feature parameters on rheological properties was also analyzed. The results show that it is reasonable and feasible to approximate the bubble size distribution of fresh concrete with pore size distribution of hardened concrete at 3d. Smaller bubbles (10–600 μm) can contribute to the reduction on the average size and spacing factor, increase the specific surface area of bubbles, significantly reduce the yield stress and plastic viscosity of sieved mortar and increase the thickness of mortar layer on the surface of coarse aggregates, then significantly increase the flowability of fresh concrete.