Geomembrane Waterproofing Materials
A geomembrane is a synthetic material that is non-permeable and is used in a number of applications within the waterproofing industry. The geomembranes are manufactured from a number of different materials to meet the requirements of different applications such as the lining of pipes, canals, dams etc.
One of the most common of these types of geomembrane are made from PVC plastic. PVC plastic sheeting is the ideal material to line uneven surfaces as the supple and adaptable nature of the material allows it to conform to irregular surfaces. PVC is highly durable and will not disintegrate or deteriorate over time allowing it to maintain its impermeable nature over a long duration.
Another popular type of geomembrane is made from bitumen also better known as tar. Unlike PVC, bitumen geomembranes do not come in sheets that are ready to use but rather in a semi liquid form that can be painted onto a surface to create a waterproof layer. There are many different applications for bitumen as a waterproofing agent.
Not as common are rubberised geomembrane materials. Rubber is highly flexible and can be used to fill in gaps and cracks that may exist in a system that needs to be waterproofed. However, rubber is not ideal for use in all applications as the material is likely to deteriorate under specific conditions or when it comes into contact with specific elements and chemicals.
Polyethylene is also widely used in the waterproofing. There are two types of polyethylene – high density and low density versions. Both these materials are highly resistant to deterioration caused by chemicals but do have other setbacks such as being very brittle and not being suitable for use in applications where they will be exposed to the UV rays of the sun.
It is important to assess the quality of a specific geomembrane material relevant to its application. There are a number of factors that will affect geomembrane quality and determine its compatibility for use in a specific process. These factors include:
- The thickness of the material
- The density of the material
- Liquid and vapour transmission features
- Vapour transmission of solvents
- Index for melt flow
- Durability or lifespan
- Overall performance.
The thickness and the density of geomembrane quality differ in the choice of application. The thickness refers to how much of the material will be necessary to be effective in a waterproofing application. The density of the material on the other hand is relevant to how closely packed the molecules in the material are and therefore how permeable it will be to liquids and gases.
Of course one of the most important features of geomembrane quality is determined by how long the material will last. In most applications it is necessary for the geomembrane material to be very durable and last a number of years and could even be expected to deliver on its waterproofing characteristics for more than a lifetime as the removal and replacement of the material in specific applications can be very difficult.