The test results shown in Fig. 2 were obtained for a vibrational
frequency in the vertical flow rate test of 25 times per 15 s. It was
found that when the vertical flow rate exceeded approximately 6%,
the voids in the concrete at the bottom were filled with paste to the
extent that the concrete’s permeability was reduced. The test results
shown in Fig. 3 were obtained for a vibrational frequency in
the vertical flow test of 50 times per 30 s. Similar results were obtained
when the vertical flow rate exceeded approximately 12%.