Stabilisation of a Subgrade Silty Clay Soil Using Chloride Compounds
Balarabe Wada Isah, PhD.
STABILISATION OF A SUBGRADE SILTY CLAY SOIL USING CHLORIDE COMPOUNDS
Pavement Engineering Seminar
Balarabe Wada Isah
Department of Geotechnical Engineering SRM University
Soil stabilization refers to the procedure in which a special soil, a cementing material, or other chemical material is added to a natural soil to improve one or more of its properties.
One may achieve stabilization by mechanically mixing the natural soil and stabilizing material together so as to achieve a homogeneous mixture or by adding stabilizing material to an undisturbed soil deposit and obtaining interaction by letting it permeate through soil voids.
Soil stabilizing additives are used to improve the properties of less–desirable rood soils. When used these stabilizing agents can improve and maintain soil moisture content, increase soil particle cohesion and serve as cementing and water proofing agents.
A difficult problem in civil engineering works exists when the sub-grade is found to be clay soil.
Many research have been done on the subject of soil stabilization using various additives, the most common methods of soil stabilization of clay soils in pavement work are cement and lime stabilization.
Terrain: Is soil erosion likely?
Categories of salt compounds:
- Efflorescent: e.g. Na2CO310H2O
- Deliquescent: e.g. Al2 (OH )3 and NaOH
- Hygroscopic: e.g. NaCl,CaCl2 , andMgCl2
This paper describes an investigation into the effect of addition chloride compounds ( NaCl, CaCl2, MgCl2) on the engineering properties of silty clay soil. The soil used in this study is brought from south of Iraq.
Characteristics of soil in southern Iraq Light brown silty clay soil representing a widely spread typical soil in the middle and southern parts of Iraq.
Consistency limit test result;
Preparation of specimens
Three types of chloride compounds were used, namely, NaCl, MgCl2, and CaCl2. Each one of these salts was dissolved in water and then mixed with soil.
The soil specimens were prepared by modified proctor test procedures according to ASTM(American Society for Testing and Materials) (D 1557).
The following tests were considered as the basis for comparism;
- Compaction test,
- Atterberg limits, and
- Unconfined compression test.
The addition of each one of the chloride compounds decreased the liquid limit and plastic limit and plasticity index for the soil.
The dry density increased and the optimum moisture content decreased with the increased in salts percentage.
The compressive strength of the soil increased with the addition of chloride compounds.
This could help improving strength and other soil properties.
Virginia Transportation Research Council (A Cooperative Organization Sponsored Jointly by the Virginia Department of Transportation and the University of Virginia)
Segment A-B (Calcium Chloride).
Segment B-C (Magnesium Chloride)
Segment C-D (Centrophase AD)
Segment D-E (EC Cryl).
Segment E-F (Soil Sement).
Segment F-G (Soiltac).
Segment G-H (TDS).
Segment H-end (Control).
Segment End-East (Soiltac Topical).