Soft Peaty Clay With the rapid development going on in the country especially in theconstruction of highways a need of competent ground is occurred more than ever.Most of the ground where the ongoing and proposed projects are to be carriedout consists of soft peaty clay and with a high water table. Peaty clay is thewhether products of organic material mixed with some inorganic soil. In SriLanka peaty clays are with organic contents around 30%-40%. (Kulathilake & Madusanka, 2011) SoilStabilization Soil Stabilization is the process of improving the physical and engineeringproperties of soil to achieve some predetermined targets. It operates invarious ways such as mechanical, biological, physical, chemical and electrical. (Nima, Ahmad, Mahmood, & Aminaton, 2015) The most trendingmethod of soil stabilization is the use of chemical additives.
Many researcheshave been conducted to identify the most effective way of using chemicaladditives. These different chemical soil stabilizers are categorized astraditional and nontraditional additives. Some traditional additives are lime,cement, fly ash and bituminousmaterials.
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Non-traditional additives are enzymes, liquid polymers, resins,acids, silicates and ions. In Sri Lanka various by products have been used withcement successfully. CCR-Calcium Carbide Residues CCR is a by-product of the acetylene production process.
It containsmostly Ca(OH)2. With the increment in the demand for the Acetylenegas in Sri Lanka CCR is produced in a large scale. It is economically andenvironmentally feasible to use CCR as it is freely available and also cleansthe environment by using it rather than racking them up. Micro-structuralCharacteristics In order to describe the theories behind stabilization process it isessential to study the changes occur in the mineralogy and the molecularcharacteristics of the soil before and after the stabilization. For that X-raydiffraction and scanning electron microscope can be used. . Problem Statement Most of the construction in Sri Lanka is to be carried out on softpeaty clay.
The soft peaty clay encountered in most of the sites highways arewith high water content, extremely compressible and processes low shearcapacity. So it is essential to improve those geotechnical characteristics ofpeaty clay using the method of soil stabilization. For that the most common way is stabilization using cement. But the useof cement in such larger scale is unbearable for a developing country like SriLanka. So a replacement for the usage of cement is vital. Significance of Research The research is to be carried out to overcome the problems mentioned inthe problem statement. If the test results proves that the geotechnicalcharacteristics of the peaty clay is considerably improved by the stabilizationprocess using CCR it will be a majorbreakthrough in the field of geotechnical engineering. Considering the currentconstruction work carried out using cement as the stabilizer it costs a greatdeal of money.
But if the CCR mixing with the cement stabilization is goodenough it will save millions for the country as CCR is a by-product of anotherindustry. It will also be verymuch environmentally friendly as until today the by- product of Acetylene gasproduction CCR is unused and racked up in factory sites causing manyenvironmental issues. So taking use of that CCR will be very beneficial. Scope of the study Many researches havebeen carried out to test the strength development by using the cement as thestabilizer. So here I will be testing the unconfined compressive strengthdevelopment and the shear strength development after 28 days of curing whencement percentage is replaced by CCR in 3 steps. With the time restrains I willonly be testing for three percentages of CCR. Cement % CCR % Sample 1 15% 5% Sample 2 10% 10% Sample 3 5% 15% Same set of sampleswill be again tested after 90 days of curing to analyze the long term strengthbehaviour.
Samples from eachdifferent mix will be tested using scanning electron microscope to study themineralogy and the microstructural characteristics of the stabilized peat. The sample we aretesting is brought from the Southern Expressway extension project. So it willbe only representing the particular site conditions. Objectives of the research · To propose the best combination of cement and CCR thatachieves the highest strength development.· To study the microstructural phenomena behind the strength developmentin stabilized soil