A dynamic removal method for concrete pile head is newly developed. The method enables us to produce the controlled horizontal fracture plane by using the charge holder with horizontal fins and a non-explosive demolition agent. The effectiveness of the presented method to produce the horizontal fracture plane was demonstrated by the model experiments with small size reinforced concrete specimens. In these experiments, the dynamic behavior of cracks propagating along the specified horizontal fracture plane was clarified by high-speed videography. The usefulness of the method on field usage was confirmed by experiments with reinforced concrete pile head of the actual size. It was shown from these experiments that the fracture plane occurred nearly horizontally at the specified position, and that the part of concrete to be removed from the pile head portion could be separated easily by lifting up action of gas pressure. It was also confirmed that smoothness of the fracture surface of the concrete pile was achieved by using the newly developed charge holders.
fracture control, charge holder, non-explosive demolition agent