K. Divya Krishnan ¹, P. T. Ravichandran ¹, C. Sudha ¹, V. Janani ¹, Manisha Gunturi ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN

Abstract

Background/Objectives: Buildable land with good natural bearing capacity is reducing and it leads to the construction of buildings on poor soils which are finally leads to structural foundation failures. This necessitated the use of available admixtures for the improvement of soil characteristics economically. Among the available resources, industrial by- products can be effectively used as admixtures since it can solve the hazardous problems due to its disposal. Methods: Grain size analysis and Atterberg’s limits tests are conducted to classify the soils used in this study. To evaluate the effect of admixtures, strengths characteristics of soils were observed by Unconfined Compressive Strength and California Bearing Ratio tests. Weak soils having high expansive characteristics are used to study the activation of 5% fly ash blended with Phospho Gypsum (PG) at varying percentages of 2%, 4% and 6% with two weak soils at different curing conditions. Findings: Results shows higher strength development upto a percentage of 4% PG with 5% flyash with both the soils. Effect of curing periods on strength characteristics of treated soils at 7, 28 and 60 days were also considered in this study. Microstructural studies are also showing an improvement in microstructure which is examined in SEM micrographs and XRD results. The influence of flyash with different percentages of phosphogypsum on swelling characteristics shows a decrease in swell potential of treated soil with increase in curing periods. Improvement: This study gives an effective application of Phospho Gypsum and Fly Ash in geotechnical field by using it as a relevant soil stabilizer. Increase in CBR values were obtained with Fly Ash and Phospho Gypsum combinations with soils, which reduces the thickness of pavement and making more productive use of industrial wastes with considerable environmental benefits.

Keywords

Compressive Strength, Fly Ash, Phosphogypusm, Stabiisation

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P. T. Ravichandran ¹, K. Divya Krishnan ¹, Manisha Gunturi ¹, C. Sudha ¹, P. R. Kannan Rajkumar ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN

Abstract

Background/Objectives: Problematic soils cause more damage to structures which are resting over it due to less strength to support the loads acting on them during the construction as well as in service periods. A proper treatment of the subgrade soil is required for providing a stable working area for the construction of structures. In geotechnical point of view, soil stabilization with suitable admixtures fulfils the improvement in the soil characteristics for construction of foundation for light structures and pavements. Methods/Statistical Analysis: In this study an attempt is made to analyse the effect of soil stabiliser RBI grade 81 on two different soils treated with varying percentages of admixture for different curing periods. The strength properties are studied by conducting the UCC and CBR test for treated soils with 2%, 4% and 6% of RBI for specific curing of 7, 28 and 60 days. Microstuctural studies by Scanning electron microscopy had done on untreated and treated soils shows the relevant structural changes which promotes the strength attainment with the addition of admixtures while curing period increases. Findings: This study shows a substantial improvement in problematic soils by treated with RBI grade 81 shows the increasing value of UCC ranging from 1.5 to 11 times and California Bearing Ratio values shows an increase of 65% and 41% from 2% and 2.19% for the both the soils with the addition of 6% RBI additives at the curing period of 60 days. Improvement/Applications: Use of RBI 81 in soil stabilisation renders a better stabilizing agent making the soils capable of meeting the constructional requirements with improved engineering properties.

Keywords

CBR, RBI 81, Soil Stabilisation, UCS

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