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Estimating Post-Tensioning Grout Bleed Resistance Using a Pressure-Filter Test
[摘要]

Grouted tendons are found in the precast, prestressed concrete industry in a number of applications, including post-tensioned tendons added for live load and continuity requirements in pretensioned  bridge girders. A key property for a high quality grout is proper bleed resistance. Bleed water trapped in the grouted duct collects at high points and forms voids, leaving steel more vulnerable to attack by aggressive agents. This paper summarizes available pressure-filter test data of grouts along with actual pumping tests over the last 34 years. The data are combined with a calculated pressure approach for determining the  required bleed resistance suitable for a particular elevation change. A procedure for carrying out a pressure filter test is given and three numerical design examples for various  post-tensioning applications are included. Recommendations are provided for structural elements with high, medium, and low elevation changes. The use of these recommendations should result in grouts   that  produce a reasonably small amount of bleed water. 

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[效力级别]  [学科分类] 建筑学
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