PURPOSE: To transfer power caused with the deformation of a form to a concrete wall to crush by burying and hardening a rock crusher of form memory alloy together with concrete.

CONSTITUTION: A form memory alloy 1 is contained into concrete of which wall, floor, ceiling and, etc., are formed, and a rock crusher having a specific form is buried at a time when concrete is placed. The rock crusher is fixed into the concrete in consideration of a crazing direction, size, etc., by thickness of the concrete. In the case the rock is crushed, the rock crusher is blockaded with a crushable rock easily, it is removed in the case of crushing, a hole as the terminal of the propagation of a crack is made, and after that, the rock crusher is heated to influence static crushing power into the concrete.