Bituminous geomembrane



Bituminous geomembrane (BGM) is a type of geomembrane consisting of a reinforcing geotextile to provide mechanical strength and elastomeric bitumen (often called asphalt in U.S.) to provide impermeability. Other components such as sand, a glass fleece, and/or a polyester film can be incorporated into the layers of a BGM. Bituminous geomembranes are differentiated from bituminous waterproofing materials used in buildings due in part to their wide roll width, which can exceed 5m, and their substantial thickness of up to 6.0mm.

These properties are designed for environmental protection, civil infrastructure, and mining applications.

History
The earliest estimated use of bitumen dates back 40,000 years to the paleolithic age and the historical use of bitumen as a waterproofing layer is extensive and well documented. Bitumen emulsion applied to polypropylene geotextiles was reported to have been used in a Navada heap leach mining installation as early as 1973. Published literature describing the modern development of the bituminous geomembrane can be traced back to the first double-liner system conceived of in 1974 by geosynthetics pioneer, J.P. Giroud. This novel bituminous geomembrane was made by spraying hot bitumen in-situ onto a polyester geotextile. Soon after these early installations, factory manufactured BGMs were developed with factory impregnation of bitumen into the geotextile allowing a high standard of quality control. Spray applied BGMs went entirely out of favor by 1988.