Modification of Mechanical Properties of Expansive Soil from North China by Using Rice Husk Ash

Cheng-Pei Feng,Mazahir M M Taha,Sara H S Ahmed

doi:10.3390/ma14112789

Cheng-Pei Feng, Mazahir M M Taha + Show 1 more

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https://doi.org/10.3390/ma14112789

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Abstract

The construction of buildings on expansive soils poses considerable risk of damage or collapse due to soil shrinkage or swelling made likely by the remarkable degree compressibility and weak shear resistance of such soils. In this research, rice husk ash (RHA) was added to expansive soil samples in different quantities of 0%, 4%, 8%, 12%, and 16% by weight of soil to determine their effects on the plasticity index, compaction parameters, consolidation performance, and California bearing ratio (CBR)of clay soil. The results show that the use of RHA increases the effective stress and decreases the void ratio and coefficient of consolidation. Adding 16% RHA resulted in the greatest reduction in the hydraulic conductivity, void ratio, and coefficient of consolidation. The void ratio decreased from 0.96 to 0.93, consolidation coefficient decreased from 2.52 to 2.33 cm2/s, and hydraulic conductivity decreased from 1.12 to 0.80 cm/s. The addition of RHA improved the soil properties and coefficient of consolidation due to the high density and cohesiveness of RHA. The results of this study can be used to provide a suitable basis for the treatment of expansive soil to provide improved conditions for infrastructure construction.

Highlights

Expansive soil is commonly known as “shrink-swell soil” and the construction of buildings on such soils are susceptible to differential settlement due to its high compressibility and weak shear resistance
The results show that the rice husk ash (RHA) improved the California bearing ratio (CBR) value and Unconfined compressive stress (UCS) of soil with 10% RHA content is recommended as optimum amount for practical purposes
To understand the effect of RHA reinforcement on the properties of expansive soil, results of liquid and plastic limit tests, compaction tests, triaxial tests, and consolidation tests are discussed

Summary

Introduction

Expansive soil is commonly known as “shrink-swell soil” and the construction of buildings on such soils are susceptible to differential settlement due to its high compressibility and weak shear resistance. Waste materials have been increasingly applied around the world for soil stabilization or improvement because of the overproduction of wastes such as RHA, fly ash, plastics, and fibres, such as in India, where about 100 million tonnes of rice is produced annually, leading to a large quantity of RHA [25]. Using such waste material to improve soil has considerably reduced geotechnical problems [26,27]. Basha et al [30] found that adding RHA to expansive soil reduced its PI and maximum dry density (MDD) and increased its optimum moisture content (OMC)

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