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Can Clay has researched the use of polyurethane rubber in chipboard packing ring for use in jacking pipe applications. The pictures in the following presentation are indicative of the loading in a lateral direction, which occurs when the chipboard is compressed longitudinally, in unfavorable materials. This test loading approximates the stresses which would occur during actual operations on microtunneling or pipe (bursting) replacement projects. The loadings were taken up to 25,000 psi (172 N/mm2) since Can Clay's Denlok pipe has compressive strengths at failure which normally approximate this. Note that the EN 295-7 (European) requires only 10, 875 psi and the American Standard, ASTM C 1208, requires only 7,000 psi. The results of this research confirms that the Eurpoean studies findings of unfavorable results when elastomeric meterials are used for packing ring (cushion ring) materials. |
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