Compressibility behavior of Boron (Tincal) added to sand-bentonite mixtures under different temperatures

Şükran Gizem Alpaydın ,Yeliz Yükselen-Aksoy

doi:10.1051/e3sconf/202020509007

Abstract

The importance of thermal behaviour of soils has increased significantly with increasing number of energy structures. There is a need for soils, which show design criteria (strength, permeability, etc.) performance during their life under high temperature or thermal cycles. In the literature studies, it was observed that the volumetric deformation of the soil changes with increasing temperature. Sand-bentonite mixtures generally act as impervious barrier in areas such as nuclear waste repositories, landfill liners etc. These mixtures will be exposed to high temperature; therefore, their engineering performance should not alter under high temperature. Boron is used in the industry for high temperature resistance, flexibility, lightness, power and ease of production. Boron minerals have very low thermal expansion and they are also resistant to thermal shocks. For that reason, the properties of sand-bentonite mixtures can be improved by boron additives at high temperatures. In this study, volume deformation behavior of sand-bentonite mixtures was determined in the presence of tincal. The oedometer tests were performed under room temperature and 80°C.

Highlights

A thorough understanding of the effect of temperature on the hydraulic and mechanical behavior of soils is crucial for many engineering applications
According to the previous studies in the literature, it has been reported that hydraulic conductivity, volumetric deformation, shear strength properties of such soils change at high temperatures [1, 2]
The sand used was classified as well-graded sand (SW) according to Unified Soil Classification System (USCS) and the grain size distribution is given in Figure 1 [18]

Summary

Introduction

A thorough understanding of the effect of temperature on the hydraulic and mechanical behavior of soils is crucial for many engineering applications. The soils which are surrounding energy structures and used as impermeable barriers in nuclear and solid waste repositories, are exposed to high temperatures and thermal cycles. The engineering properties of these soils can be adversely affected as a result of temperature changes. Bentonite or sand-bentonite mixtures are generally used as impermeable barriers in waste repositories. According to the previous studies in the literature, it has been reported that hydraulic conductivity, volumetric deformation, shear strength properties of such soils change at high temperatures [1, 2]. The resistance of fabric changes against temperature is explained with clay interparticle forces and viscous shear resistance of adsorbed water [3]

Methods

Results

Conclusion