| 摘要 |
A concrete permeability testing core comprises a cylinder of polymeric foam enclosed within an elastomeric envelope under tension. When placed in a cylindrical concrete mold in an axially concentric orientation, it can be used to form a concrete test specimen with a cylindrical cavity. After the concrete is cured and the outer concrete mold is removed, the polymer foam can be collapsed by contacting it with solvent for the foam. The elastomeric envelope, being under tension, contracts to a smaller size, permitting easy removal from the concrete and leaving a nascent cavity surface.
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