STABILIZATION OF EXPANSIVE SOIL USING GROUND GRANULATED BLAST FURNACE SLAG Sharmila.S 1

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1 STABILIZATION OF EXPANSIVE SOIL USING GROUND GRANULATED BLAST FURNACE SLAG Sharmila.S 1 1 Assistant Professor, Department of Civil Engineering,Kongu Engineering College,Perundurai Abstract Expansive soil have the tendency of swelling when it is in contact with water and shrinks when they dry out. Ground improvements associated with swelling and shrinkage characteristics of expansive clays cause serious distress to the structures. Soil stabilization using chemical admixtures is the oldest and popular method of ground improvement. This study deals with the suitability of waste material like GGBS as soil stabilizers for use in construction of buildings and pavements in expansive soil Because these materials are being dumped in open pits which may be a hazard to the environment. So this method ultimately turns to be an eco-friendly type of stabilization. Initially the physical properties of the expansive soil, GGBS are studied by Wet sieve analysis and liquid limit tests. Then for the purpose of determining the optimum moisture content and the strength of the virgin and the stabilized materials the Standard Proctor Compaction Test and California Bearing Ratio Test have been conducted. The results of the experimental research show that these waste materials can be effectively used as soil stabilizers for pavements and buildings as the CBR value is increased. Keywords Expansive clay, GGBS,Liquid limit and CBR I. INTRODUCTION Expansive soils are a worldwide problem that poses several challenges for Civil Engineers. Expansive soils cause more damage to structures and pavements, than any other natural hazard, including earthquakes and floods. Expansive soil will also exert pressure on the vertical face of a foundation, basement or retaining wall resulting in lateral movement. Shrink-swell soils which have expanded due to high ground moisture experience a loss of soil strength or capacity and the resulting instability can result in various forms of foundation problems and slope failure. Expansive soil should always be a suspect when there is evidence of active foundation movement. Extensive laboratory / field trials have been carried out by various researchers and have shown promising results for application of such expansive soil after stabilization with additives / stabilizers. There are many different reasons for using stabilization, Ultimately the main reason for using stabilization will usually be cost savings. For stabilization to be successful, the material should attain the desired strength and should retain its strength and stability indefinitely. Pavement design is based on the premise that minimum specified structural quality will be achieved for each layer of material in the pavement system. II. SOIL COMPACTION Soil compaction is the rearrangement of soil aggregates and/or particles in a denser way when the voids and pores mainly between the aggregates and particles become smaller or even missing in comparison with the arrangement of similar but not compacted soil. Aggregates are arranged with the longer side in a horizontal way (platy structure), they do not have a round shape but one side is much longer than the other and, depending on intensity of compaction, they can be totally destroyed if the compaction is too severe. Certain advantages resulting from soil compaction have made it a standard procedure in the construction of earth structures, such as embankments, subgrades, and bases for road and airfield pavements. No other construction process that is applied to natural soils produces so marked a change in their physical properties at so low a cost as compaction (when it is properly controlled to produce the desired results). Principal soil properties affected by compaction include: DOI: /IJMTER FVHB2 102

2 Settlement. Shearing resistance. Movement of water. Volume change International Journal of Modern Trends in Engineering and Research (IJMTER) Fig 1. Soil compaction III. EXPERIMENTAL WORKS Ground Granulated Blast Furnace Slag Slag is defined as the solid material resulting from the interaction of flux and impurities in the smelting and refining of metals. Ground Granulated Blast Furnace Slag (GGBFS) is a by product of the steel industry. Blast furnace slag is defined as the non-metallic product consisting essentially of calcium silicates and other bases that is developed in a molten condition simultaneously with iron in a blast furnace. In the production of iron, blast furnaces are loaded with iron ore, fluxing agents, and coke. When the iron ore, which is made up of iron oxides, silica, and alumina, comes together with the fluxing agents, molten slag and iron are produced. The molten slag then goes through a particular process depending on what type of slag it will become. Air-cooled slag has a rough finish and larger surface area when compared to aggregates of that volume which allows it to bind well with portland cements as well as asphalt mixtures. GGBFS is produced when molten slag is quenched rapidly using water jets, which produces a granular glassy aggregate. Tests on soil The following tests were carried out to find the characteristics of soil Wet sieve analysis Liquid limit Standard proctor compaction test California bearing ratio test Figure 3 and 4 shows that the tests conducted on soil All rights Reserved 103

3 International Journal of Modern Trends in Engineering and Research (IJMTER) IV. RESULTS AND DISCUSSION The following tables and figures shows the results of various tests on clay and GGBS Table 1 Classification Test results for Clay Wet Sieving Material Grain size distribution Gravel Sand Fines Liquid limit Plastic limit Plasticity index IS classification GGBS Non plastic 0 SM Liquid Limit Table 2 Classification test results for GGBS PROPORTION (CLAY:GGBS) LIQUID LIMIT% 100: : : : :40 30 Standard Proctor Compaction Test Table 3 Results Of Liquid Limit S.NO Wt of the mould with soil (Kg) Bulk Density (γ b) (g/cm 3 ) Water content Dry Density (γ d) (g/cm 3 ) Table 4 SPCT on Clay FIG 4 SPCT on All rights Reserved 104

4 S.NO International Journal of Modern Trends in Engineering and Research (IJMTER) Wt of the mould with soil (Kg) TABLE 5 SPCT on Clay and GGBS (60:40) Bulk Density (γ b) (g/cm 3 ) Water content Dry Density (γ d) (g/cm 3 ) California Bearing Ratio Test FIG 5 SPCT on Clay and GGBS mix FIG 6 CBR Test On Clay And GGBS Mix V. CONCLUSION From the test results, the following conclusions have been drawn: The stabilization process of clay with ground granulated blast furnace slag is very effective. The CBR value of clay is increased from 0.9% to 9%.Addition of GGBS to expansive subgrade not only reduces expansive nature of subgrade but also increases its CBR value. Reduction of expansive nature of subgrade and increase of CBR value reduces the overall thickness of pavement.reduction of overall thickness of pavement offsets the overall cost. Hence the addition of GGBS to clay soil improves its engineering All rights Reserved 105

5 International Journal of Modern Trends in Engineering and Research (IJMTER) REFERENCES [1] Ghani, F., Masroor Alam, M., Naushad Beg, M., Stabilization / solidification of hazardous nickel electroplating waste using blast furnace slag, Journal of the Institution of Engineers (India), Vol. 90, p , September [2] Gopal. R.,Rao, A. S. R., Basic and applied soil mechanics, New Age international Publishers, New Delhi, [3] Robert Brooks, M., Soil stabilization with fly ash and rice husk ash, International Journal of Research and reviews in Applied Sciences, Vol. 1, No. 3, p , December [4] Samson, M., Selvi, P., Velliangiri, K. B., A study on Engineering properties of cement stabilized seashore soils, National Building Material and Construction Week, p , January All rights Reserved 106