Shear-Resistant Geosynthetic Clay Liners—About 30 Years from Invention to Today

In the late 1980s a shear-resistant sandwiched product of geosynthetic textile layers and bentonite clay was invented and introduced to the field of geotechnics in Germany. The product consists of a needle-punched nonwoven/woven fabric combination as carrier layer, a powdered layer of bentonite clay as sealing element and a second needle-punched nonwoven as cover layer, all layers connected by a needle-punching operation. By this needle-punching operation a long-term shear-resistant connection of all layers is achieved to transmit shear forces from the cover layer across the bentonite layer (very low internal shear strength when hydrated) to the carrier layer. Very rapidly this new product was accepted around the world as a new sealing element in geotechnical and hydraulic engineering applications. Currently, more than about 1 billion m² has been used worldwide up to now, saving about 1 million tons of natural clay. Today the “shear-resistant geosynthetic clay liner” (shear-resistant GCL) is a standard geosynthetic product being produced and used all around the world. Early applications were in hydraulic and environmental applications, but also many others, such as waterproofing in construction engineering, infrastructure applications and many more. The GCL applications development was accompanied by significant research with activities around the world which also leads to new questions and answers for clay sealings in general. Professor Robert M. Koerner supported the GCL development as prominent leader with great personal commitment and visions.