Ageing of exposed geomembranes at locations with different climatological conditions

2015 ◽  
Vol 52 (3) ◽  
pp. 326-343 ◽  
Author(s):  
R. Kerry Rowe ◽  
A.M.R. Ewais
Keyword(s):  
High Pressure ◽  
Crack Resistance ◽  
Induction Time ◽  
High Density Polyethylene ◽  
High Density ◽  
Cold Climate ◽  
Field Conditions ◽  
Research Site ◽  
Hot Climate ◽  
Exposure Conditions

The degradation of high-density polyethylene (HDPE) geomembranes exposed to the elements depends, inter alia, on the climatological conditions. This study investigates the degradation in the properties of HDPE geomembranes installed at two mine facilities after almost 16 years of exposure in a warm–hot climate and at a research site after 6 years of exposure in a mild–cold climate. Samples were exhumed at the field sites from different locations and the properties of the geomembrane were measured in the laboratory. The depletion of antioxidants detected by the standard oxidative induction time (Std-OIT) test for the geomembrane installed at the research site was faster on the slope than on the base; however, there was negligible difference in the depletion of antioxidants–stabilizers detected by the high-pressure oxidative induction time (HP-OIT) test between the slope and base. Under the field conditions described, the antioxidant depletion time for the exposed geomembrane installed at the research site (mild–cold climate) was inferred to be 20 to 54 years. The exposed HDPE geomembranes installed at the mine facilities (warm–hot climate) have reached the time of nominal failure based on their stress crack resistance. However, they have not ruptured under the exposure conditions even though the stress crack resistance has dropped to as low as 70 h at some locations.

Effect of texturing on the longevity of high-density polyethylene (HDPE) geomembranes in municipal solid waste landfills

2020 ◽  
Vol 57 (1) ◽  
pp. 61-72 ◽  
Author(s):  
M.S. Morsy ◽  
R. Kerry Rowe
Keyword(s):  
Municipal Solid Waste ◽  
Crack Resistance ◽  
Solid Waste ◽  
Induction Time ◽  
High Density Polyethylene ◽  
High Density ◽  
Smooth Edge ◽  
Core Thickness ◽  
Municipal Solid Waste Landfills ◽  
Solid Waste Landfills

The effect of texturing (co-extrusion using blowing agent) on the longevity of a geomembrane (GMB) when immersed in synthetic municipal solid waste leachate is investigated over a ∼3 year period. Based on data at four temperatures (40, 55, 75, and 85 °C), the time to antioxidant depletion of the textured portion of a 1.5 mm core thickness high-density polyethylene (HDPE) GMB is 40% (standard oxidative induction time) and 9% (high-pressure oxidative induction time) faster compared to the 1.5 mm smooth edge of the GMB. However, despite this, stress crack resistance results show that texturing may have no significant effect on the time to nominal failure for this GMB. It is also shown that HDPE GMBs made from nominally the same resin but from different production lots have different rates of stress crack resistance degradation and hence time to nominal failure; this should be considered both in landfill design and landfill construction quality assurance.

Antioxidant depletion in high-density polyethylene (HDPE) geomembrane with hindered amine light stabilizers (HALS) in low-pH heap leach environment

2016 ◽  
Vol 53 (10) ◽  
pp. 1612-1627 ◽  
Author(s):  
R. Kerry Rowe ◽  
Fady B. Abdelaal
Keyword(s):  
High Pressure ◽  
Induction Time ◽  
High Density Polyethylene ◽  
Incubation Temperature ◽  
Low Ph ◽  
High Density ◽  
Residual Value ◽  
Heap Leach ◽  
Residual Values ◽  
Hindered Amine Light Stabilizers

Antioxidant depletion from a high-density polyethylene (HDPE) geomembrane with hindered amine light stabilizers (HALS) immersed in seven different low pH solutions is examined over a 3 year period. The examined solutions had the range of pH (0.5, 1.25, and 2.0) likely to encompass the pH of the leach solutions found in copper, nickel, and uranium heap leach pads. The metal concentration for these solutions is adopted from copper raffinate solutions. Additional solutions are investigated to examine the effects of field practices such as using surfactants in the leach solutions and pre-curing of the ores used to improve the metallurgical response of the ore. For the antioxidants detected by standard oxidative induction time (Std-OIT), there was a depletion to residual value of about 20% of the initial Std-OIT that varied depending on the incubation temperature and pH of the solution whereas decreasing the pH from 2 to 0.5 did not significantly affect the depletion rates of Std-OIT. The antioxidants detected by high-pressure oxidative induction time (HP-OIT) exhibited the fastest depletion in pH = 1.25 with the highest residual values followed by pH 2.0 and the slowest HP-OIT depletion was in pH = 0.5, but with the lowest residual values. Arrhenius modelling is used to predict the length of the antioxidant depletion stage for each solution based on both Std-OIT and HP-OIT.

Effects of exposure conditions on the depletion of antioxidants from high-density polyethylene (HDPE) geomembranes

2002 ◽  
Vol 39 (6) ◽  
pp. 1221-1230 ◽  
Author(s):  
Henri P Sangam ◽  
R Kerry Rowe
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Induction Time ◽  
High Density Polyethylene ◽  
High Density ◽  
Accelerated Ageing ◽  
Time Intervals ◽  
Msw Landfill ◽  
Exposure Conditions

Laboratory-accelerated ageing tests have been conducted to examine the depletion of antioxidants from high-density polyethylene (HDPE) geomembranes as a result of their exposure to various environments. Samples of 2.0 mm thick geomembrane were exposed to air, water, and municipal solid waste (MSW) leachate at temperatures of 22, 40, 55, 70, and 85°C. At various time intervals, samples were collected and the oxidative induction time (OIT) was evaluated. The results indicated that the antioxidants are depleted at rates 1.6 to 2.4 times faster for samples in water than for air-exposed samples. For samples in leachate, the depletion is about 4 times faster than that in air and 1.6–3.2 times faster than that in water. Using these rates, it is estimated that if the geomembrane examined were used as an MSW landfill primary liner, it would take at least 40 years to deplete the antioxidants from the geomembrane at a temperature of 33°C and over 150 years at a temperature of 13°C.Key words: ageing, antioxidants, durability, oxidative induction time, HDPE geomembrane, antioxidant depletion time.

Pressure Effects on the Lifetime of Gas High Density Polyethylene Pipes

2021 ◽  
Author(s):  
Yang Wang ◽  
Hui-qing Lan ◽  
Tao Meng ◽  
Bing Wang ◽  
Du du Guo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Induction Time ◽  
High Density Polyethylene ◽  
Reaction Rate ◽  
Low Pressure ◽  
Gas Pressure ◽  
High Density ◽  
Pressure Effects ◽  
Polyethylene Pipes ◽  
Hdpe Pipes

Abstract The purpose of this study was to propose low gas pressure effects on lifetime of natural gas high density polyethylene (HDPE) pipes by thermal-oxidative aging (TOA). The new method to assess the lifetime of HDPE natural gas pipes is based on gas pressure testing. An approach to monitor oxidative induction time (OIT) has been used to predict lifetime. Natural gas HDPE pipes were used to evaluate the effects of low gas pres-sures on oxidative induction time. In order to emphasize the pressure effects, relatively low temperatures at 45, 55, 65 and 75 °C were utilized for the exposure. The low-pressure conditions were created using air at levels of 0, 0.1, 0.2, 0.3 and 0.4 MPa. The property of high density polyethylene pipes was effectively moni-tored using the low pressure oxidative induction time (OIT) test. The results show that the aging reaction rate of high density polyethylene pipes increased exponentially with temperature and gas pressure according to the Arrhenius equation. Analytical models were developed to predict the aging reaction rate and lifetime of natural gas HDPE pipes.

Long-term performance of high-density polyethylene (HDPE) geomembrane seams in municipal solid waste (MSW) leachate

2017 ◽  
Vol 54 (12) ◽  
pp. 1623-1636 ◽  
Author(s):  
R. Kerry Rowe ◽  
Mohamad Shoaib
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Induction Time ◽  
High Density Polyethylene ◽  
High Density ◽  
Depletion Rate ◽  
The Times ◽  
Long Term Performance ◽  
Term Performance

The effect of a synthetic municipal solid waste leachate on the long-term performance of dual-wedge welds in a 1.5 mm thick high-density polyethylene geomembrane (GMB) is reported based on 4 years of testing at 40, 65, 75, and 85 °C. The effect of leachate on the GMB well away from the weld, in the heat-affected zone (HAZ) beside the weld, and in the welded zone are investigated. The slowest antioxidant depletion rate was in the weld itself and the fastest rate for the HAZ adjacent to the weld. The shear break and peel break properties started to decrease after the standard oxidative induction time had depleted to residual, but before the high-pressure oxidative induction time had reached residual. Failures occured at the HAZ adjacent to weld in both the shear and peel tests. No failure of the seam itself was observed. The times to nominal failure of the GMB in the critical HAZ are predicted. The rate of degradation in the weld and sheet are compared.

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