The Use of the Stepped Isothermal Method for Estimating the Long-Term Creep Modulus, Creep Strain and Strength of Polyethylene Pipe Resins [PE]

# 2010 Vancouver

The Stepped Isothermal Method (SIM) is a special form of Time-Temperature-Superposition (TTS) that has been used to predict long-term creep behavior from very short-term tests (~ 24 hours). A single test specimen undergoes a series of short-term (10,000 seconds) creep tests, each separated by 7ºC. At the end of the experiment, one obtains a series of creep curves, each at a different temperature. The results are shifted based on known TTS techniques to create a master curve. Creep modulus and creep strain are determined under lower loads, while creep rupture times can be determined under higher loads. SIM was originally developed in these laboratories on high strength polyester (PET) geotextiles and geogrids for soil reinforcement applications. The results on PET, Kevlar, Nylon, and PP have correlated well to conventional creep results. Polyethylene is a special case because as the temperature is increased, both the creep rate and the effective stress are changing simultaneously as the material becomes softer. It is basically a stepped-temperature and stepped-stress test. This paper describes the details of the test, presents some results on recycled-containing HDPE resins, and shows how SIM relates to sustained burst tests on crosslinked polyethylene (PEX) and a PE 3408, pressure rated pipe. The results suggest that SIM might be useful for selecting stresses in sustained burst test programs, act as a screening tool for formulation designs or preliminary assessment of resins, or provide some long-term property information for situations where it is not possible to test pipe. It may also prove to be useful for quality assurance.

Please note that the whole article content is available on PPCA website onlySource : 2010 Vancouver


Related papers

ACCELERATED PIPE TEST METHODS TO EVALUATE PE 100-RC MATERIALS – POSSIBILITIES FOR ISO STANDARDISATION

Author(s) : Thomas R. Kratochvilla, Raimund Eremiasch, Christoph Bruckner 2018 Las-Vegas

In the last years effort has been made to develop and standardise new accelerated test methods to evaluate PE 100-RC materials in short times in form of test bars. The two most important developments, the cracked round bar test (CRB test) and the strain hardening test (SH test) were published as final ISO standards in...

GUIDELINES FOR CORRUGATED HDPE PIPES MANUFACTURED WITH RECYCLED MATERIALS FOR HIGHWAY CULVERT AND STORM DRAIN APPLICATIONS

Author(s) : Michael Pluimer, Richard Thomas 2018 Las-Vegas

Over the past decade, there have been several key research projects to evaluate the performance of corrugated HDPE pipes manufactured with post-consumer and postindustrial recycled materials for highway and railroad drainage applications. Three of these projects were recently completed and published (NCHRP Project...

MOLECULARLY ORIENTED AWWA C909 PIPE FOR SEISMIC APPLICATIONS

Author(s) : Richard St-Aubin, Dr. Thomas O’Rourke, Dr. Brad Wham, Blake Berger 2018 Las-Vegas

Molecularly oriented polyvinyl chloride (PVC-O) pipe has been found to withstand large ground deformation during seismic events without damage. The properties of PVC-O pipe that support this performance have been investigated in a multi-year testing program undertaken at the Geotechnical Lifelines Large Scale Testing...

SLOW CRACK GROWTH RESISTANCE OF NON-VIRGIN POLYMERS

Author(s) : Andreas Frank, Isabelle J. Berger, Mario Messiha, Carl-Gustaf Ek, Norbert Schuler, Jens-Martin Storheil, Erwin Mayrbäurl, Steve Heeley, Frank Krause, Lodewijk Niemöller, Philippe Gabriëls, Yogesh S. Deshmukh, Florian Arbeiter, Thomas Koch, Gerald Pinter 2018 Las-Vegas

In order to improve the circular economy of polymers in terms of sustainability and reduced carbon footprint, the increased use of recyclates has become a topic of major importance. Due to their long design lifetimes, pipe applications represent an excellent opportunity to create added value to non-virgin polymers. In...

THE WORLD'S FIRST CLASS 3 SAFETY RELATED NUCLEAR PE4710 PIPING PROJECT – 10 YEAR REVIEW

Author(s) : Lonnie Corley, Dane Chang, Harvey Svetlik, Matt Brandes, Thomas Musto, Frank Schaaf, David Fink 2018 Las-Vegas

This paper presents a brief overview of a challenging project at the Callaway Nuclear Power Plant where HDPE was utilized to replace degraded steel buried piping in a Safety Related water system. Callaway was the first Nuclear Power plant to obtain NRC approval and successfully place the HDPE piping system into...

A COMBINATION OF ACCELERATED TEST METHODS TO EVALUATE NEW GENERATION RESINS FOR DISINFECTANT- RESISTANT POLYETHYLENE PIPES

Author(s) : Francis Reny Costa, Anh Tuan Tran, Jeroen Oderkerk, Thomas Hjertberg, Christophe Salles, Ulf W. Gedde, Benjamin Rabaud, Flavia Zraick 2016 Berlin

The premature failure of polyethylene pipes in contact with high chlorine and chlorine dioxide, used as residual disinfectants in drinking water distribution, remains an area of concern for water companies particularly in regions where temperatures are regularly or seasonally high. Multiple factors can amplify the...

MECHANICAL STABILIZATION OF RIGID PVC COMPOSITIONS

Author(s) : Thomas C. Pedersen, Robert R. Kwapisz 2016 Berlin

This paper presents rheological data on simple rigid PVC compositions lubricated paraffin wax, calcium stearate, and oxidized polyethylene wax. These three materials comprise the most widely used lubricant system for rigid PVC in North America. The influence of certain paraffin wax characteristics will be discussed....

POTENTIALS OF TERAHERTZ TECHNOLOGY FOR THE INSPECTION OF PLASTIC PIPES

Author(s) : Stefan Kremling, Thomas Hochrein, Peter Heidemeyer 2016 Berlin

In plastics industry, the use of terahertz technology opens up opportunities for novel non-destructive and contactless testing applications. For example, the thickness of individual layers of a foamed multilayered plastic pipe can be monitored contactless and continuously during the extrusion process. Furthermore,...

PREDICTING SERVICE LIFE FOR RECYCLED PE MATERIALS VIA THE UNNOTCHED CONSTANT LIGAMENT STRESS (UCLS) TEST

Author(s) : Michael Pluimer, Rick Thomas 2016 Berlin

A new test method was developed to evaluate the stress crack resistance of HDPE materials containing recycled content. The method involves testing un-notched specimens in an elevated temperature bath under a specified stress. The new test method was published in March of 2016 as ASTM F3181, Standard Test Method for...

150 Years Lifetime on PE-Piping Systems for Drinking Water, Can It Be Achieved?

Author(s) : Tomas Helenius, Karin Jacobson, Thomas Blomfeldt 2014 Chicago

Polyethylene is the leading material for new installation of drinking water pipes in Sweden. The material is recognized by the market as a flexible, light weight and an inexpensive solution. The material is ideal for water piping, however the lifetime is only guaranteed for 50 years. This is a problematic limitation...

Members of the Association

BOREALISBOROUGEINEOS O&PIRPCKorea Petrochemical IND. Co., LTDLyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
TOP