Abstract: To improveengineering properties of soil and making the soil more stable soil stabilizationmethods are used. This paper highlights soil stabilization by using cement. Cementis a material which is added to natural soil for the purpose of stabilization. The main purpose of the soil stabilization isto increase the bearing capacity of the soil.
its resistance toweathering process and soil permeability. Unstable soils can create significantproblems for pavements or structures, therefore soilstabilization techniques are necessary to ensure the good stability of soil,this paper deals with the complete analysis of improvement of soil propertiesby using cement.Key words: cement, soil, compactors, liquid limit, plastic limit,shrinkage limit.INTRODUCTION: soil stabilization is used to reduce thepermeability and compressibility of soil mass in earth structures and toincrease its shear strength. soil stabilization required to increase thebearing capacity of foundation soils.
The main use of stabilization is toimprove the natural soils for the construction of highways and airfields. Thelong-term performance of any construction project depends on the soundness of theunderlying soils. The mainprincipal of stabilization are used for controlling the grading of soils andaggregates in the construction of bases and sub-bases of the highways andairfields. Cement stabilization is done by mixing pulverized soil and Portlandcement with water and compacting the mix to attain a strong material. Thematerial obtained by mixing soil and cement is known as soil-cement thesoil-cement becomes a hard and durable structure material as the cementhydrates and develops strength.TYPES OF SOIL-CEMENT 1.
Normal soil-cement: Consists of 5 to14% of cementby volume. The quantity of cement mixed with soil is sufficient to produce ahard and durable construction material. The quantity of water used should bejust sufficient to satisfy hydration requirements of the cement and to make themixer workable.2. Plastic soil-cement: This type of soil-cement alsocontains 5 to 14% by volume, but it has more quantity of water to have wetconsistency similar to that of plastering mortar at the time of placement. Theplastic soil cement can be placed on steep or an irregular slope where it isdifficult to use normal road-making equipment .
it has also been successfullyused for water-proof lining of canals and reservoirs. The plastic soil-cementcan be used for protection of steep slopes against erosive action of water.3. Cement modified soil: it is a type of soil-cementthat cantinas less than 5% of cement by volume. It is a semi-hardened productof soil and cement. S.
no properties Local soil 1 Liquid limit (%) 43 2 Plastic limit (%) 28 3 Shrinkage limit (%) 19 4 Specific gravity (%) 21 5 Gravel (%) 2.67 6 Sand (%) 4 7 Silt (%) 50 8 Clay (%) 26 9 Natural moisture content (%) 23 10 Maximum dry density (gm/cm^3) 8 11 Plasticity index (%) 1.98 12 Optimum moisture content (%) 16 Table 1:physical properties of soilMATERIAL AND METHODS:Constructionmethods:1.
mix-in-place method: in this method of construction,mixing of soil-cement is done at the place where it would be finally placed. itconsists of:The sub grade is cleared of all undesirable materials such asboulders, debris; stumps. it is then leveled to the required formation level.The leveled sub grade is scarified to a depth equal to the proposed thicknessof the soil cement.
The required of water is sprinkled over the surface and wetmixing is done till the mixture has a uniform colour. Compaction is done usingsuitable methods. The thickness of the layer should not be more than 15 cm. compactionshould not take more than 2hours.The compacted soil-cement is moist cured for at least 7 daysby providing a bituminous primary coat.
The pulverized soil is properly shaped to the required gradeand the required quantity of cement is spread uniformly over the surface. It isthen intimately mixed dry with rotary tillers or mixers. 2. plant-mix method:Stationary plant: in this method, the excavated soil istransported to stationary plant located at a suitable place. The requiredquantity of cement is added to the soil in the plant. Mixing is done afteradding water. The time required depends upon the type of the soil.
The mixedmaterial discharged in6to dumper trucks and transported back to the sub grade. itis spread and properly compacted. The stationary plant is useful for obtaininga uniform mix. The method quite expansive as compared with mix-in-place method.
Travelling plant: a travelling plant can move along the road under construction.The soil, after placement of cement over it, is lifted up by an elevator anddischarge into the hopper of the mixer of the travelling plant. Water is addedand proper mixing is done. The mix is then discharge on the sub grade andspread by a grader. It is then properly compacted.
The travelling plant method,like stationary plant, is useful for accurate proportioning and uniform mixing.The depth of treatment also properly controlled and a uniform sub grade surfaceis attained.CEMENT STABILIZED SUBGRADECONSTRUCTION PROCEDURE Construction of cement stabilized sub grade soil followsthis procedure:Sub grade material was spread on the top of embankment layer(150mm + 25% loose) and lightly compacted.
Total work area marked with grids ofthe area required for one bag of cement (2.5m X 2.5m) .
Cement spread at therate of one bag per grid. Soil and Cement mix by mechanical Harrow followed bytractor mounted rotovator. Moisture added to the soil (+/-1% of OMC). Compactionis process completed done. Quality Control tests conducted as per thefrequency. Fig-1Soil stabilization by using cement Fig-2Soil stabilization by using cement CONCLUSION:Improve the mechanical qualities of local road construction soils.
Strength gain is primary outcome due to chemical reaction between the soil andcement. Increase load bearing capacity of soil by which maintain its structuralintegrity. Harmful moisture penetration can be diminish gradually from thesoil. This process of cement stabilization is economic which in turn reducesthe cost of construction and will lasts longer life of the road.REFERENCES:1 currin.D.
D.,allen. J.j.little, D.N.
,1976.validation of soil stabilization index system with manual development.Frank j. seisler research laboratory.
United States air force academy, Colorado.2 Broms,B.B., 1986.stabilization of soft clay with lime and cement columns in southeast asia.
applied research project.3 Das,B.,1994.principleof geotechnical engineering,3rd edition.PWS_kent publishing company,boston.4 Derucher,K.N.
,korfitatis, G.P., ezeldin. A.S., materials for civil and highwayengineerings.prentice-hall.5Dr.K.R.arrora of geotechnical engineering of soil mechanics and foundationengineering.6Sadek,D.,roslan,H., abubakar,D.A.,2008.engineering properties of stabilized tropicalpeat soils.bund,EJGE13,pp 7-87saitoh,S.Y.,Suzuki,shirai.,1985.hardening of soil improvement by deep mixing method.proc.of the 11thISCMFE,san Francisco,vol.3