In this report, we conducted a questionnaire survey targeting contractors who perform placing and compaction of concrete, and investigated the actual conditions of placing and compaction. As a result, the description of compaction in JASS 5 is the standard for compaction of ordinary concrete, so the number of workers, the number and the rod diameter of internal vibrators, etc. been determined according to the construction conditions. In addition, there were many opinions that it was expected that the possibility of problems such as poor filling could be reduced with the spread of high fluidity concrete.
