Experimental investigation of air-dried and oven dried lateritic soil samples and influence on their properties

Experimental investigation of air-dried and oven dried lateritic soil samples and influence on their propertiesPresented byKrishnappa H09GT09FUnder the guidance ofDr B.M Sunil

1Outline Introduction Literature reviewObjectiveMethodology Results References

2Introduction : Lateritic Soils Laterization is the removal of silicone through hydrolysis and oxidation that results in the formation of laterites and lateritic soils.

Location : Laterites and lateritic materials occur frequently throughout the tropics and subtropics.

Degree of laterization : defined as intense concentration of haematite in soils.

Method of preparationAir dried soil samples air dried under normal ambient temperature in shed, 25-300c.

Oven dried soil samples dried in an electrical oven to constant weight at 1100 c

3Condition of laterization Availability of iron rich minerals in parent bed rock.High soil permeability and ground water movement through soil.Presence of ample oxygen in the percolating ground water in order to form iron oxide.Presence of primarily neutral or acid geochemical environment.4Objective To find the index properties of the air dried lateritic soil.

To find the index properties of the oven dried lateritic soil.

Comparison of properties of both air dried and oven dried lateritic soil.

5Methodology

Collection of soil samples from different part of NITK.Experimental investigation of index properties of soil sample.

Interpretation of results.

Discussion on results6Location of samplesPrediction of the engineering behavior of the ground requires knowledge of the variation of the soil in situ.

Details of locality are :Native vegetation - rainforestAnnual rainfall 2000mmAverage daily max. temperature - 32Landform western ghats of coastal India.Distribution of samples Area > 150 acres, Depth limited to few meters.7Literature reviewCoreia (1969), Result of the fractional identification of three lateritic gravels.

Morin (1969), Mineralogy and index properties of some african lateritic residual soil.

Ruddock, (1969), Properties and position in lateritic ground :Some statistical relationships.

Za-chieh Moh,(1969), Effects of method of preparation of index properties of lateritic soils.

8Summary of literature reviewFrom literature survey it has been observed that air or oven drying reduced the liquid and plastic limit value.

Greater changes observed in soils containing montmorillonite.

The high iron content contributes to the high strength and low compressibility of lateritic soil.9Experimental work carried out All soils from different four sites were tested accordance with the procedures outlined in ASTM(1965).

Physical properties determined include :Specific gravityGrain size distributionLiquid limit, plastic limit, shrinkage limits.Compaction testCBR test.

10Oven dried samplesCore cutter Dry density g/ccWater content % Specific gravitySieve AnalysisGravel %Coarse sand %Medium sand %Fine sand %Sample 11.72315.262.5760102010Sample 21.812.462.6420204614Sample 31.9318.132.5642182614Sample 41.6420.492.583616381011Air dried samplesCore cutter Dry density g/ccWater content % Specific gravitySieve AnalysisGravel %Coarse sand %Medium sand %Fine sand %Silt &ClaySample 11.72914.802.56501022144Sample 21.8412.652.61243630100Sample 31.86110.162.58531324100Sample 41.7518.42.55421828120Results 12Oven dried samplesCompaction Dry density g/ccOMC% Hydrometer AnalysisCBRClay %Silt%Unsoaked soakedSample 11.82616.527.8222.189.62.62Sample 21.96911.6927.3622.6214.37.29Sample 31.93614.8927.5622.4418.292.91Sample 41.7821727.2622.7426.271.4Air dried samplesCompaction Dry density g/ccOMC% Hydrometer AnalysisCBRClay %Silt%Unsoaked soakedSample 11.93915.5326.9123.0971.22Sample 21.89814.9827.3922.6114.34.37Sample 31.86715.2827.7522.2576.781.81Sample 41.82917.0627.6322.370.580.87Conclusions The results presented above clearly indicate that the method of sample preparation prior to the testing has effect on the Atter-berg limits and grain-size distribution of lateritic soils.13ReferencesCoreia (1969), Result of the fractional identification of three lateritic gravels.

Morin (1969), Mineralogy and index properties of some african lateritic residual soil.

Ruddock, (1969), Properties and position in lateritic ground :Some statistical relationships.

Za-chieh Moh,(1969), Effects of method of preparation of index properties of lateritic soils.

14Thank you15