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OCR for page 47
47 mulations met the required cell class for AASHTO M294. Table 23. Properties for AASHTO M294 pipe resin Pipe A2 met all requirements except for NCLS. Pipe B3 met (cell class 335500). all requirements except for the density requirement. Pipe B5 Property Requirement met all except for the density and NCLS requirements. Density 0.948-0.955 g/cm3 Five of the six pipes made from the final candidate formu- MI <0.4 g/10 min lations met the NCHRP Report 631 recommendation for creep % Carbon Black 2%5% Yield Stress 3,500 psi modulus and yield stress (long term property requirements). Flexural Modulus 110,000 psi Note that the long-term tests were performed on plaques made NCLS Stress Crack >24 h from manufactured pipe. This was done to erase all previous OIT >50 min stress due to manufacturing to facilitate the comparison of the blended resins without the influence of differences in manu- facturing (such as manufacturing speed). Additional tests Ultimately, all the resin tests should be performed on should be performed on specimens cut directly from the pipe. Parallel plate tests were performed on the finished pipe prod- compression molded plaques from the pipe itself, but resin uct made from the six final candidate formulations. The results specifications will allow independent compounders and pipe indicate that all six final candidate formulations meet the pipe manufacturers to make appropriate blends and control their stiffness requirement of AASHTO M294. properties. Once more, a specification on the recycled material For the pipes herein made with blends of virgin and recycled itself will be beneficial to resin compounders and pipe manu- HDPE that have material properties meeting the requirements facturers. Therefore, five different specifications are proposed in Table 12.12.3.3-1, current AASHTO LRFD Section 12 design and presented in Appendices E through I. The titles and scopes specifications should apply; however, long-term in-situ load of each one are shown below. tests and accelerated laboratory tests on finished pipe product embedded in soil are needed to finalize the proposed changes Appendix E--Proposed Draft Standard to the AASHTO LRFD design methodology (i.e., structural Specification for PCR MCR High-Density design equations for thrust, buckling, and bending and resis- PE Bottles for Use in AASHTO-Approved tance factors based on field performance data). Corrugated Drainage Pipe Proposed Draft Specifications 1. Scope 1.1 This specification covers the quality of PCR, MCR, Currently, both AASHTO M252 and M294 have property high-density PE bottles for use in AASHTO approved requirements for both the virgin resins used to make the pipe corrugated drainage pipe. and the pipe itself. And the National Transportation Prod- 1.2 This specification presents a set of properties to be met uct Evaluation Program (NTPEP) requires the use of a PPI- for the resin. certified resin, or the testing of each different blend used to 1.3 This specification can be used by recycled-resin sup- make pipe. It is well known that some pipe manufacturers pliers as part of manufacturing quality control (MQC), make their own virgin blends, while others prefer to use cer- or by pipe manufacturers or independent bodies as tified and listed resins. manufacturing quality assurance (MQA). A similar situation would exist if AASHTO allows the use of recycled material containing resins to make pipe. Some manufacturers will prepare their own blends and others will Appendix F--Proposed Draft Standard choose to purchase fully compounded pipe resins already con- for Recycled Content Containing HDPE taining recycled HDPE. For this reason, it is suggested that Resin Formulations for Corrugated there should be both required resin properties and required Pipe Made to AASHTO Standard pipe properties in the specifications for M252 and M294 appli- M252-Recycled cations allowing recycled HDPE. It is also suggested that the specifications move away from listing cell classification by 1. Scope ASTM D3350. Cell classification is a living standard subject to 1.1 This specification covers the quality of HDPE-resin for- continuous revisions, which have affected the AASHTO stan- mulations containing recycled HDPE that are intended dards in the past. Also, there are tests in the cell classification for use in AASHTO M252--Recycled approved cor- that may not be necessary in D3350 and tests that are necessary rugated drainage pipe for subsurface drainage applica- but are not in D3350 (NCLS, OIT). So, instead of a required tions, in sizes 75- to 250-mm diameter (3 to 10 in.). cell class, the standards could simply have a table of required 1.2 The recycled PE may be either post-consumer or post- properties, like is shown in Table 23. industrial.

OCR for page 47
48 1.3 This specification presents a set of properties and test This standard does not purport to address all of the safety frequencies to be met for the resin. concerns, if any, associated with its use. It is the responsi- 1.4 This specification can be used by suppliers of resin con- bility of the user of this standard to establish appropriate taining recycled PE as part of MQC, or by pipe manu- safety and health practices and determine the applicabil- facturers or independent bodies as MQA. ity of regulatory limitations prior to use. Appendix G--Proposed Draft Standard Appendix I--Proposed Draft Standard Specification for Recycled Content Specification for Corrugated Polyethylene Containing HDPE Resin Formulations Drainage Pipe Containing Recycled for Corrugated Pipe Made to AASHTO Polyethylene, 300- to 1,500-mm Diameter Standard M294-Recycled 1. Scope 1. Scope 1.1 This specification covers the requirements and methods 1.1 This specification covers the quality HDPE-resin formu- of tests for corrugated PE pipe, couplings, and fittings lations containing recycled HDPE that are intended for for use in surface and subsurface drainage applications. use in AASHTO M294Recycled approved corrugated 1.1.1 This standard allows for the use of recycled PE in drainage pipe, in sizes 300- to 1500-mm (12- to 60-in.) the pipe, but not in the couplings nor the fittings. diameter. 1.1.2 Nominal sizes of 300 to 1,500 are included. 1.2 The recycled PE may be either post-consumer or post- 1.1.3 Materials, workmanship, dimensions, pipe stiff- industrial. ness, slow crack growth resistance, joining sys- 1.3 This specification presents a set of properties and test tems, brittleness, and forms of markings are frequencies to be met for the resin. specified. 1.4 This specification can be used by suppliers of resin con- 1.2 Corrugated PE pipe is intended for surface and sub- taining recycled PE as part of MQC, or by pipe manu- surface drainage applications where soil provides sup- facturers or independent bodies as MQA. port to its flexible walls. Its major use is to collect or convey drainage water by open gravity flow, as culverts, storm drains, and so forth. Appendix H--Proposed Draft Standard Note 2--When PE pipe is to be used in locations where Specification for Corrugated Polyethylene the ends may be exposed, consideration should be given Drainage Pipe Containing Recycled to protection of the exposed portions due to combus- Polyethylene, 75- to 250-mm Diameter tibility of the PE and the deteriorating effects of pro- longed exposure to ultraviolet radiation. 1. Scope 1.3 This specification does not include requirements for 1.1 This specification covers the requirements and methods bedding, backfill, or earth cover load. Successful per- of test for corrugated PE pipe, couplings and fittings formance of this product depends upon proper type for use in subsurface drainage systems, storm sewers, of bedding and backfill, and care in installation. The and in surface drainage (culverts), where soil support structural design of corrugated PE pipe and the proper is given to the pipe's flexible walls in all applications. installation procedures are given in AASHTO LRFD 1.2 This standard allows for the use of recycled polyethylene Bridge Design Specifications, Section 12, and LRFD Bridge in the pipe, but not in the couplings nor the fittings. Construction Specifications, Section 30, respectively. 1.3 Nominal sizes of 75 mm to 250 mm are included. Upon request of the user or engineer, the manufacturer 1.4 Material properties, dimensions, pipe stiffness, per- shall provide profile wall section detail required for a forations, joining systems, and forms of marking are full engineering evaluation. specified. 1.4 The following precautionary caveat pertains only to the Note 1--When PE pipe is to be used in locations where test method portion, Section 9.4 of this specification. the ends may be exposed, consideration should be This standard does not purport to address all of the safety given to combustibility of the PE and the deteriorating concerns, if any, associated with its use. It is the responsi- effects of prolonged exposure to ultraviolet radiation. bility of the user of this standard to establish appropriate 1.5 The following precautionary caveat pertains only to the safety and health practices and determine the applicabil- test method portion, Section 9.3, of this specification. ity of regulatory limitations prior to use.