Abstract: As there is no unified and definite evaluation index for vibration compactness of concrete, we use orthogonal tests to study the characteristics of vibration energy, hardened concrete pore structure, density, compressive strength, and splitting tensile strength under different working conditions. The effects of various hardening property indexes on concrete compaction evaluation are compared and discussed through variance analysis. The results show that vibrating time period influences vibrating intensity only at the beginning of vibration, and vibration energy in propagation does not linearly attenuate but decrease significantly near the vibration source. For hardened concrete, porosity increases with the increasing distance from the source where it takes the maximum. And compared with pore size distribution, vibration energy has less influence on vertical variations in porosity. Moreover, concrete density varies markedly only within a distance of eight centimeters from the source, and spatial distributions of compressive and splitting tensile strengths are featured with significant fluctuations. This study concludes that porosity is a more suitable index for evaluating concrete compactness relative to other indicators and a prediction model can be built based on the characteristics of fresh mixture and vibration energy.

Key words: concrete vibration, compaction, evaluation indexes, hardening properties, variance analysis, characterization