Abstract:

Stabilization is the improvement of geotechnical properties of clays such as consistency, strength and compression by using pozzolanic additives. Today, it is one of the most preferred methods because it is easily applicable and economical. With this method, which is applied by adding certain amounts of additive to clayey soils, the geotechnical properties of clay can be improved by the pozzolanic reaction occurring in the soil. In this method, natural pozzolanic materials such as tuff, volcanic ash, shale, and diatomite have been used with the unnatural pozzolans such as lime, fly ash, silica fume, cement and resin as additives. However, it is important to make stabilization using only natural or both natural and unnatural pozzolans since it is more economical. In this study, the textural changes in high plasticity clay were investigated when using of natural and unnatural pozzolans. For this purpose, in the laboratory studies, slaked lime, silica fume, fly ash and tuff were used as additives. Variations in the consistency and texture of the clay due to the effects of different kinds and proportions of additives were investigated. According to the results obtained from the study, it was determined that the liquid limit (LL) values ​​decreased significantly in the samples where the unnatural and natural additives were used together. Scanning Electron Microscopy (SEM) studies were performed in all samples. The images obtained by SEM studies showed that in the cases where the maximum decrease in LL values ​​occurred, significant agglomeration occurred as a result of pozzolanic reaction. As a result of the agglomeration in these samples, increase in grain sizes and intergranular spaces were observed. However, in the samples where the reduction in LL is limited, agglomeration was not sufficiently developed and the grains are more plaque-shaped.  

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