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Air voids remaining on the concrete surface are detrimental to the durability. Surface voids also affect the esthetics of concrete structures. In this study, the method of reducing the surface voids caused by entrapped air of fresh concrete was verified using 122 cases of vibration box tests with different materials, mix proportions, vibration frequencies, and amplitudes. The surface void area ratio (SVAR) decreased when the acceleration of the vibration box was increased regardless of the type of concrete. The relationship between SVAR and acceleration can be expressed through a power function. However, a segregation was observed in medium‐fluidity concrete when the acceleration exceeded 4.0 Gal (hereinafter referred to as G). In addition, the SVAR correlated with the mortar rheological constant was measured using a steel ball pull‐up test. An equation using mortar rheological constants, which can be estimated using a concrete slump, was proposed to predict the SVAR‐acceleration relationship.

This paper shows the effect of coarse aggregates in concrete with perfobond rib via experimental and FE analysis. First, the model of a single PBL in ordinary concrete was reproduced through a three-dimensional nonlinear FE model. Coarse aggregates were added to the model; it was found that the coarse aggregates around the perforation of PBL increased its initial load-carrying capacity. Furthermore, the interlocking of these coarse aggregates was found to affect PBL behavior after the peak of loadcarrying capacity. Next, analytical numerical modeling of push-out tests of single PBL was performed to investigate the role of coarse aggregates. It was confirmed that the initial load-carrying capacity could be increased via the vertical loading stress from the steel to the coarse aggregates. Finally, the numerical modeling results were verified by actual push-out tests of single PBL with systematically sorted coarse aggregates.

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