A Study on Void Characteristics with V-meter in Top-Down Column Joint Part.

초음파를 이용한 역타기둥 이음부의 공극특성에 관한 연구

When top down method is used, it could be a construction method trouble in column joint, between the former concrete and the latter. It could bring a void and weak concrete in column. The purpose of this study is finding a way to prevent concrete void and concrete suitable for top down , through V-metering for top down column and concrete experiment. To minimize the void of reverse placement joint, It is more effect to use the sheath method then direct method in concrete placement.