| 摘要 |
<p>A method for breaking or fracturing concrete particularly in the form of a concrete slab (10) forming a floor in a multi-storey building. The method includes placing support beams (20) across an area (18) of the slab (10), the beams (20) being supported at its ends on portions of the slab (10) outside the area (18) and coupled at one or more locations within the area (18) to the slab (10). A through cut is formed about substantially the full perimeter (26) of the slab with a plurality of blind holes (12) drilled in area (18). Propellant is inserted into at least some of the holes (12), the propellant burning within 10-15 milliseconds of ignition and developing a gas pressure in the range of 100-150 MPa. Holes (12) are stemmed typically with a particulate settable stemming material prior to ignition of the propellant.</p> |
