抄録
Fresh concrete, even high fluidity concrete is a special granular material rather than a purely viscous fluid. Obviously, its deformation resistance is greatly affected by its granular properties. When shear deformation takes place in fresh concrete, normal strain on shear plane will occur simultaneously, which is well known as dilatancy phenomenon of granular material. Dilatancy occurs essentially due to the existence of particle contact angle. The particle contact angle also greatly affects the flow resistance of fresh concrete, and changes with concrete's flow or vibration. In this study, in order to clarify the granular characteristics of fresh concrete, mechanical behaviors of a glass particle-silicon oil system in sheared state were firstly examined. Then, we performed the one-side shear test and vibration test to investigate the change of particle contact angles (PCAs) in sheared and vibrated states, using Laser-Aided Tomography (LAT). Also, the influencing factors of mean PCA were discussed, including shear stress, shear deformation, normal stress, particle shape, size distribution of particles, elapsed time of vibration, and vibration acceleration, etc.
