MATERIALS | WATERPROOF MEMBRANES
They investigated the correlation between
results from the single-point notched constant tensile load-stress crack resistance test and strain hardening modulus. This was carried out for both aged and unaged specimens. The strain hardening modulus was calculated based on the (force-elon- gation) raw data from the tensile strength test carried out at room temperature. Three different approaches were used to define
Above: Chinese researchers have used a 2D model to assess the barrier properties of a typical composite liner system
recycling the used geotextile after the project’s completion. Switch looked at ways to remove the geotextile with minimal sand content, while Solmax developed a recycling process. Through pilot-scale trials and refinement, they established an effective method. The process had to overcome the chal- lenge of extracting soil particles so that the resulting material was suitable for reuse in the production cycle.
Extra capacity Solmax Americas recently expanded manufactur- ing of geomembranes in Houston, Texas. “We are focused on improving quality, reliability
and flexibility of our geomembrane product offering,” said John Henderson, president of Solmax. The facility produces the company’s HDPE and LLDPE geomembrane liners that make up its GSE product line. The plant – which runs 24/7 – employs around 130 people. It includes an onsite test facility and also hosts the company’s in-house custom fabrication team – which designs polyethylene liners and components for a range of applications. As well as geomembranes, the Houston plant
also produces geonets and geocomposites in the Fabrinet line.
Research results Geomembranes are heavily researched, as there are many ways to raise their performance – from lifetime estimation to performance assessment. Canadian researchers, for instance, have used
strain hardening to predict the stress crack resist- ance of black HDPE geomembranes. “The service life of an aged buried HDPE geomembrane liner can vary from several decades to centuries, depending on factors such as the geomembrane material, temperature, in-contact fluid, and the level of stress/strain applied,” said the researchers, from the geoengineering centre at Queen’s University in Kingston.
16 FILM & SHEET EXTRUSION | May 2024
the strain hardening modulus and to compare the strain hardening modulus with the test. The research- ers showed that a high-test speed – carried out at 7 mm/min at room temperature – provides a good correlation for smooth black HDPE geomembranes. “The proposed method and equation are only valid for traditional MDPE geomembranes,” the researchers concluded. “Further research is needed for other types of geomembranes on the market.” The research was published earlier this year in Geotextiles and Geomembranes.
Barrier properties Another recent paper, in Environmental Engineer- ing & Technology, used a 2D model to assess the barrier properties of a composite liner system. A composite liner system – typically consisting of a geomembrane and geosynthetic clay liner (GCL) – is often used to prevent toxic landfill leachate from migrating into the environment. “In landfills, contaminant migration into the soil
and groundwater can be reduced by a geomem- brane,” said the researchers, from Shanghai University in China. “However, hazardous constitu- ents from rainfall infiltration, corrosion or chemical reactions can still transport through. In view of this, a GCL is necessary to diminish the effect of geomembrane failure by adsorbing contaminants.” It is difficult to evaluate the barrier capacity of such a system, especially in the case of defects and two-dimensional (2D) scale, said the researchers. So, they developed a 2D model to determine contaminant transport through a flawed liner. The soil contaminant concentration profiles
generated by the model were found to be in good agreement with the results from lab experiments and numerical simulations, implying that it can serve as an efficient, easy-to-use estimation tool. Results showed that a GCL can reduce the pollution level caused by geomembrane failure.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.solmax.com �
www.agru.at �
www.queensu.ca �
https://en.shu.edu.cn
www.filmandsheet.com
IMAGE: SHUTTERSTOCK
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