Performance of Corrugated Pipe Manufactured with Recycled Polyethylene Content (2011) / Chapter Skim
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Once the blends were made, key relationships were developed that allowed one to predict the properties of blends so that optimized formulations could be used in the next phase to make actual pipe. Phase 3 -- Pipe made from Recycled-Resin Blends The purpose of this phase of the project was to manufacture dual wall corrugated drainage pipe out of resin formulations containing recycled HDPE.
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An understanding of this graph is necessary to develop test methods to characterize the long-term behavior of PE. It shows three distinct stages of aging.
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The PE pressure pipe industry has used this failure envelope for many years to ensure the quality of resins used for gas and water distribution pipelines. The main protocol for this is ASTM D2837, "Standard Test Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials or Pressure Design Basis for Thermoplastic Pipe Products." For medium- and high-density PE pipe, the method requires that at least 18 data points are generated at room temperature with one point over 10,000 h (1.14 years)
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growth. This is shown in Figure 3, and one can see that the failure mechanism has transitioned from Stage I to Stage II at the stresses evaluated.
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buried structures and most recently on HDPE resins used for corrugated drainage pipe. It has been validated for PP by comparing SIM results to conventional creep results.
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An example SIM test for HDPE was performed under the following conditions: • Sample: Type I Dumbbell. • Strain Measurement: Extensometer.
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until the two parallel lines line up. The matching of the slopes of the end of one step with the beginning of the next step is the critical step for accurate extrapolations.
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11 0 5 10 15 20 25 30 35 40 -4 -3 -2 -1 0 1 5 82 63 4 7 9 LOG TIME (hr)
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The contaminants present can be locations for stress cracks to grow. How quickly a crack grows will depend on the size, shape, and hardness of a particle along with the inherent stress-crack resistance of the resin or resin blend.
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* The Transportation Research Board, the National Research Council, the Federal Highway Administration, the American Association of State Highway and Transportation Officials, and the individual states participating in the National Cooperative Highway Research Program do not endorse products or manufacturers.
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And there are many in-between. Some will be happy just selling reprocessed recycled HDPE and others will want to prepare and sell fully formulated blends directly to the corrugated pipe manufacturer.
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