A comparison of shrinkage cracking between clay minerals by crack parameters using image analysis

Nhat Dai Vo

doi:10.32508/stdj.v20ik4.1107

Abstract

Experiments have been conducted in laboratory to present a comparison of shrinkage cracking based on an observation and a quantitative determination of crack parameters. Photographs of surface cracks for three different types of clay mineral belonging to different groups – Bentonite, Kaolinite and Illite – are processed using image analysis. Each of soil types is tested with four sample thicknesses ranging from 5 to 20 mm at an interval of 5 mm. The measurements of crack parameters for clay mineral soils show that area and width of cracks in case of Bentonite are much larger than those while length of cracks appears to be slightly less than that in other cases. Number of cracks in case of Bentonite are smaller than those in cases of Kaolinite and Illite. Additionally, compared with Illite, area, length and width of cracks in case of Kaolinite are slightly larger while the other crack parameters seem to be same.

Highlights

As water evaporates from the soil surface, the tensile stress develops in the soil system
Area and width of cracks formed by Bentonite are much larger than those by other clay mineral soils, i.e. Kaolinite and Illite
A comparison of shrinkage cracking between three types of clay mineals is examined by observing and measuring the quantity of several crack parameters

Summary

Introduction

As water evaporates from the soil surface, the tensile stress develops in the soil system. The soil tends to crack when the tensile stress exceeds the tensile strength. A large number of papers investigated on soil cracking have been recently published since cracking in soils has been the subject of investigation for many years. Image analysis has been widely used to analyze and determine the quantitative as well as qualitative measurements of soil cracking. A theoretical study on soil cracking was developed by Morris et al [8] based on elasticity theory, the transition between tensile and shear.

Methods

Results

Conclusion