Performance enhancement of sand–bentonite mixture due to addition of fiber and geosynthetic clay liner

Abstract

In the absence of impermeable natural soils, compacted sand–bentonite mixture along with a layer of geosynthetic clay liner (GCL) is used as a liner material at the waste disposal site. However, due to desiccation, the bentonite present in the liner shrinks resulting in an increase in the hydraulic conductivity of the liner. To prevent the desiccation cracking of bentonite, glass fibre is added to the mixture as a reinforcing material. However, the addition of the fibre can influence the geotechnical properties of liner material. To study the effect of the fibre on the geotechnical properties of the sand–bentonite mixtures with one layer of GCL, glass fibre of 10 mm length was added in the proportion of 0.5 and 1.0% to different sand–bentonite mixtures. Result shows that the swelling pressure and swelling potential of the soil–bentonite mixture with a layer of GCL decreased significantly with the increase in the glass fibre content in the mixture. The hydraulic conductivity of the mixtures was decreased with the inclusion of the GCL to mixtures; however, it increased considerably when glass fibre was added to the mixture. The compression index of the mixtures with GCL decreased marginally due to the inclusion of fibre.