Geomembranes can be classified into column-point geomembranes and rough-surface geomembranes, which are further divided into four categories: single-rough-surface geomembrane, double-rough-surface geomembrane, single-column-point geomembrane, and double-column-point geomembrane.
Geomembranes can also be categorized based on thickness: those with a thickness below 0.8mm are referred to as impermeable membranes, while those with a thickness of 0.8mm or above are called waterproof boards. Additionally, there are distinctions between column-point-surface geomembranes and rough-surface geomembranes. So, what are the differences between column-point and rough-surface geomembranes?
Column-point geomembranes feature small raised columns on the base sheet, which is evident from their appearance. In terms of production process, these columns are formed by pressing the sheet with a roller that has recessed column-point patterns before it cools and solidifies, resulting in column protrusions on the base sheet and forming a column-point-surface geomembrane. Its advantages lie in ensuring corresponding physical properties, meaning it meets high-quality requirements, including tensile strength and elongation. However, its downside is an increased overall weight per unit area, translating to higher production costs.
Rough-surface geomembranes, on the other hand, are created by roughening the original surface of the base sheet, which reduces its original thickness. Consequently, their physical properties are lower than those of the base sheet.
In summary, for the same base sheet, column-point-surface geomembranes are more expensive than rough-surface geomembranes, but they offer superior physical properties, i.e., better product quality. Some may argue that rough-surface geomembranes have a higher friction coefficient than column-point geomembranes, which is undeniable. However, in practical engineering applications, the forces between geomembranes and geotextiles can be substantial. Given that column-point geomembranes have higher quality and can withstand greater forces for the same base sheet, while rough-surface geomembranes, despite their higher friction coefficient, have inferior quality and are more prone to damage. Therefore, a higher friction coefficient is not always advantageous.
