| 摘要 |
The present invention relates to an apparatus for expanding a punched hole (11) of a concrete member, which includes: a guide part (110) inserted into the punched hole (11); a bit part (120) which is installed on an upper part of the guide part (110), and has a number of crushing protrusions (121) formed around an edge so as to crush an inner plane of the edge of the punched hole (11); and a driving part which applies rotary force or hitting force as to the bit part (120). The present invention can increase adhesive force with a filler by increasing roughness on the inner plane of the punched hole, by suggesting the apparatus (100) for expanding the concrete punched hole. |
