Abstract:

Stabilization, which is very preferred today because it is an easily applicable and economical method, occurs because of the pozzolanic reactions occurring between the additive materials added to the clayey soil and the soil. The pozzolanic reactions cause molecular changes in the soil. The most common way to detect these changes is the Fourier Transform Infrared Spectroscopy (FT-IR) method. In this study, FT-IR studies were carried out on the samples prepared using fly ash and silica fume, acidic and basic tuffs as additives and cured for 28 days, and molecular changes after stabilization were investigated. From the analysis, a new peak was formed at 1431 cm-1, which is related to the (Ca, Mg) CO3 stretch in the sample using basic tuff. In the sample using fly ash, a new peak was determined at 1416 cm-1 wave number associated with C-S-H and C-A-S-H compounds formed because of pozzolanic reactions with the effect of CaO ratio. In the example in which silica fume and basic tuff was used together, new peaks were formed at 1363 cm-1 and 1431 cm-1 wave numbers, and these peaks were associated with the (Ca, Mg) CO3 stretching. In the example in which acidic tuff and fly ash was used, two new peaks with wave numbers of 1363 cm-1 and 1416 cm-1 were formed, associated with calcite formation in the form of C-S-H and C-A-S-H compounds. According to the results of study, the examples in which pozzolanic reactions developed best are the 10% basic tuff + 10% silica fume added sample, and 10% acidic tuff + 10% fly ash added sample.

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