Modification of Asphalt Used for In-field Hot Wrapping

Field Application of heated asphalt in pipe trench, a technique popularly adopted in pipeline maintenance services, always fails to achieve the desighed quality due to many causes. The wrapping technique with modified asphalt iVstudied in order to improve the current coating process. The performances of the modified asphalt are described; higher resistance against plant root penetration; higher softening point with the same ductility as original. The specifications for the tapes are given. The superiorities ot heated tape wrapping technique over asphalt coating are introduced; simple operation, low requirement on pipe surface pretreatment, less environmental pollution, and high coating quality. Therefore, this technique is applicable to the pipeline maintenance, holiday repairng and joint coating.