Document Type : Research Article
Authors
1
Associate Professor, Faculty of Engineering, Hormozgan University, Bandar Abbas, Iran.
2
Assistant Professor, Faculty of civil Engineering, Hormozgan university
3
Master student of civil Engineering, Hormozgan university
Abstract
Proximity of soil with pollution caused by landfills changes its pH.On the other hand, due to the heat generation potential of high-level waste, the used clay coating is exposed to different thermal regimes, which leads to changes in its physical, mechanical, and microstructural characteristics. Based on this, the aim of this article is to investigate the simultaneous effect of pH changes and thermal regimes in high-level waste disposal centers. In this study, the combined effect of pH and temperature on the behavior of marl soil was evaluated using unconfined compressive strength tests, weight loss and Atterberg limits, determination of carbonate amount by titration, X-ray diffraction (XRD) and SEM images. For this purpose, HCl and NaOH solutions have been used to change the pH. After the pH of the marl soil was fixed at 4, 6, 8.3, 11 and 13, the samples were dried in the oven, then exposed to the thermal levels of 25, 100, 300, 500, 700 and 900 degrees Celsius for 2 hours. One of the most important results of this research is the removal of carbonate in acidic conditions and prominent changes in the engineering characteristics of marl soil in the thermal range of 500 ℃ to 900 ℃. Palygorskite mineral is destroyed in stable acidic and alkaline environment at 700 ℃ with the occurrence of dihydroxylation. On the other hand, the removal of carbonate in an acidic environment has led to an increase in plasticity properties and a change in the classification of marl soil.
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