Effect of Salt Content on the Evaporation and Cracking of Soil from Heritage Structures

Kai Cui,Chen Yang,Mingming Hu,Xiaozheng Zhao,Guanchang Xie,Meng Jingjing

doi:10.1155/2021/3213703

Abstract

The degree of damage to heritage structures in arid areas can be particularly serious due to long-term exposure to a harsh arid climate. In this paper, the characteristics of evaporation and cracking of soil taken from heritage structures with different NaCl concentrations are experimentally investigated by subjecting saturated soil samples taken from the Wang-Jing tower in Weihui City, Henan Province. Making soil sample of water content of 110% is used to test the rate of evaporation at a constant temperature and humidity, through which the changes in the evaporation rate, water content, fracture development, and fracture fractal dimension are obtained. The results show that, (1) with higher water content, NaCl can affect the evaporation process by increasing the matrix suction of the soil of the Wang-Jing tower and then affect the cracking process of soil. When 0%, 1%, 2%, and 4% NaCl are added, the residual water content of the samples is 3.15%, 4.23%, 4.82%, and 5.89%, respectively, which show an obvious trend of increasing water content; (2) the period with a stable fracture fractal dimension of the samples is shortened with an increase in NaCl concentration, and its maximum fractal dimension is reduced in turn; and (3) at a lower water content, NaCl crystallizes and precipitates in the pores of the soil, which provide a cementitious effect among the soil particles, thus inhibiting crack development.

Highlights

Academic Editor: Meng Jingjing e degree of damage to heritage structures in arid areas can be serious due to long-term exposure to a harsh arid climate
When 0%, 1%, 2%, and 4% NaCl are added, the residual water content of the samples is 3.15%, 4.23%, 4.82%, and 5.89%, respectively, which show an obvious trend of increasing water content; (2) the period with a stable fracture fractal dimension of the samples is shortened with an increase in NaCl concentration, and its maximum fractal dimension is reduced in turn; and (3) at a lower water content, NaCl crystallizes and precipitates in the pores of the soil, which provide a cementitious effect among the soil particles, inhibiting crack development
Based on the evaporation rate with time, the evaporation process can be divided into three stages: the first stage is a constant rate of evaporation, the second stage is a decreasing rate of evaporation, and the final stage is the residual evaporation stage

Summary

Introduction

Academic Editor: Meng Jingjing e degree of damage to heritage structures in arid areas can be serious due to long-term exposure to a harsh arid climate. Heritage structures in arid lands, such as in northwestern China, face special challenges due to extreme temperature ranges, wind, and dry desert air, which accelerate the deterioration of ceramic, porcelain, and earthly materials such as clay and adobe bricks, with various degrees of damage [1]. When the initial water content of the soil taken from the heritage structures in arid lands is less than 5%, its strength and durability decrease during the freezethaw cycle, which eventually results in severe loss of strength of the material [4]. Li et al (2021) and Yang et al (2020) studied the development of surface cracks on soil with biomass ash by using image processing technology and the fractal theory. Tension cracks in soil slopes significantly reduce their stability by allowing deeper and faster infiltration of water into the slopes. e formation of tension cracks depends on the type of soil, the degree of drying of the slope surface, and the availability or lack of water [16,17,18,19]

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Results

Conclusion