Shrinkage Curves for Powder and Granular Bentonites

Martin Wijaya,Eng Choon Leong,Hossam Abuel-Naga,A Tarantino,E Ibraim

doi:10.1051/e3sconf/20199207009

Martin Wijaya, Eng Choon Leong + Show 3 more

Open Access

https://doi.org/10.1051/e3sconf/20199207009

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Abstract

Bentonite is one of the most commonly used materials in geotechnical engineering applications especially for isolation purposes due its low permeability and its highly expansive nature. For instance, Geosynthetic Clay Liners (GCL) self-healing ability relies on the swelling properties of the bentonite to close any holes in the GCL while the low permeability of the bentonite serves to reduce the infiltration of leachate to the surrounding soil. However, different types of bentonite have different shrinkage or swelling properties and hence affects the effectiveness of the GCL. A method to assess the wetting/drying induced volume change of the bentonite is through its shrinkage curve. This paper focuses on the shrinkage behaviour of reconstituted granular and powder bentonites which are used in GCL. Photogrammetry method is used to measure the volume change of specimen during drying. The shrinkage curves of the bentonites are then compared with other bentonites from the literature.

Highlights

Bentonite is a highly expansive, low permeability soil with wide applications
One of the applications is in geosynthetic clay liners (GCLs)
In GCL, a thin layer of bentonite sandwiched between two layers of geotextile held together, generally by using needle punching

Summary

Introduction

Bentonite is a highly expansive, low permeability soil with wide applications. One of the applications is in geosynthetic clay liners (GCLs). In GCL, a thin layer of bentonite sandwiched between two layers of geotextile held together, generally by using needle punching It is commonly employed as a low permeability barrier in waste disposal facilities to minimize the migration of leachate into the underlying soils and to the groundwater [1]. Geosynthetic clay liners are generally installed at the as-rolled gravimetric water content of 10 to 15% and hydrated by allowing the bentonite to adsorb water from the underlying soils [2]. The shrinkage curve is commonly determined as a series of discrete data points. The shrinkage curves of granular and powder bentonites are determined by photogrammetry method. The results are compared with shrinkage curves of other bentonites from the literature

Experimental method

Granular and powder bentonite

Findings

Conclusion