Subgrade Black Cotton Soil Stabilization Using Ground Granulated Blast-Furnace Slag (GGBS) and Lime, an Inorganic Mineral

Bhanu Prakash Darsi,Kumar Molugaram,Saisantosh Vamshi Harsha Madiraju

doi:10.3390/iecms2021-09390

Bhanu Prakash Darsi, Kumar Molugaram + Show 1 more

Open Access

https://doi.org/10.3390/iecms2021-09390

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Publication Date: Mar 11, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Osmania University, University of Toledo

Abstract

The rapid growth of population and fast urbanization has resulted in the reduction of the good quality of available land. Black cotton (BC) soil is one of such problematic soils, though they are very fertile soils, they are not suitable for the foundation of roads and buildings. They are expansive clays with a high potential for shrinking or swelling as a result of changing moisture content. Due to the intensive shrink-swell process, surface cracks appear during dry seasons. A small amount of rainfall, such as 6mm can make these soils impassable for all traffic. About 23% of the area in India is covered by BC soil. To utilize expansive soils effectively, proper ground improvement techniques are to be adopted. One of the most widely used techniques is to stabilize the expansive soil with conventional admixtures like lime, GGBS, cement, and fly ash. In the present study, an attempt is made to modify the engineering properties of black cotton soil. This research work presents the improvement of engineering characteristics of expansive soils using Lime and GGBS as an additive. For experimental work, Lime of 2%, 4%, and 6% used and corresponding 5%, and 10% of GGBS is used. Tests like the California Bearing Ratio (CBR) test, Unconfined Compression Strength (UCS) test, proctor test, Atterberg’s limits performed. After stabilization, it was found that UCS and CBR of soil increased significantly.

Highlights

Subgrade soil is an important part of the road pavement structure as it provides support to the pavement layers like a subbase, base, and wearing courses from beneath
The results indicated that with the addition of Ground Granulated Blast Furnace Slag (GGBS) to black cotton soil the maximum dry density increased, and optimum moisture content decreased
Liquid Limit, plastic limit, and plasticity index of soil decreased with the addition of Lime and GGBS. addition of GGBS causes flocculation of clay particles and increases the number of coarser particles which helps in reducing the Atterberg limits The maximum dry density (MDD) was increased by 9.9 % and the Optimum Moisture Content (OMC) of Block Cotton Soil was by decreased 41.17 %

Summary

Introduction

Subgrade soil is an important part of the road pavement structure as it provides support to the pavement layers like a subbase, base, and wearing courses from beneath. The properties of subgrade soil are very important for the design of a pavement structure. Any weakness in subgrade soil affects all the overlying layers of pavement especially flexible pavement. The subgrade should possess enough stability under adverse climatic conditions to provide support to the pavement. The formation of waves, corrugations, rutting, and shoving in blacktop pavements are due to poor subgrade conditions. Soil subgrades of granular nature will be having increased strength as compared to fine-grained soil [1]. In some places natural soil available may be of this category and transportation of quality soil for replacement and pavement construction may involve huge costs. Some of Minerals 2020, 10, x; doi: FOR PEER REVIEW www.mdpi.com/journal/minerals

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