Abstract: In order to investigate the influence of vibration on the change of pore structure in the process of concrete condensation, the indoor simulation of vehicle-bridge vibration was carried out, and the influence of vibration in different concrete setting time on the mechanical properties of concrete was studied by setting different vibration test parameters. And the change of concrete pore structure after vibration was analyzed by using microscopic image analysis technology. The results show that: the pore area ratio and the number of pores decrease to some extent before applying the vibration with small vibration frequency and amplitude (5Hz, 4mm) during concrete initial setting period, which improves the later strength of concrete. The larger vibration frequency and amplitude (9 Hz, 8 mm) affect the concrete structure, especially from the initial setting period to the final setting period. The larger vibration will destroy the concrete structure, produce certain cracks, increase the number of holes and reduce the strength to a certain extent. There is a good correlation between the strength of concrete and the proportion of the number of holes and the area of holes. The strength of concrete can be reflected by the proportion of the number of holes and the area of holes.

Key words: bridge engineering, vehicle-bridge vibration, concrete, image analysis, pore structure

摘要： 为探究振动对混凝土凝结过程中孔结构变化的影响，采用室内模拟车桥振动，通过设置两种不同振动试验参数(9 Hz, 8 mm及5 Hz, 4 mm)，研究在混凝土不同凝结时间段振动对混凝土力学性能的影响程度，并利用显微镜图像分析技术对振动后混凝土孔结构的变化进行分析。研究表明：在混凝土初凝前施加较小频率和振幅(5 Hz,4 mm)的振动，能在一定程度减少孔面积比例与孔数，对混凝土后期强度有所提高；而较大振动频率和振幅(9 Hz，8 mm)作用对混凝土结构有所影响，特别是初凝至终凝期间，较大振动作用会对混凝土结构产生破坏，产生一定裂隙，孔数有所增加，导致强度降低；混凝土强度与孔数和孔面积比例之间有较好的相关性，可通过孔数与孔面积比例反映混凝土强度。

关键词: 桥梁工程, 车桥振动, 混凝土, 图像分析, 孔结构