Reliability of Multi-Method Mineralogical Identification in Expansive Soils
Gazi University Journal of Science, cilt.39, sa.3, ss.1463-1472, 2026 (ESCI, Scopus, TRDizin)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 39 Sayı: 3
- Basım Tarihi: 2026
- Doi Numarası: 10.35378/gujs.1912448
- Dergi Adı: Gazi University Journal of Science
- Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus, TR DİZİN (ULAKBİM), Academic Search Ultimate (EBSCO), Biomedical Reference Collection: Corporate Edition (EBSCO), Engineering Source (EBSCO)
- Sayfa Sayıları: ss.1463-1472
- Anahtar Kelimeler: Clay mineralogy, Expansive soil, Methylene blue test, SEM-EDX, XRD
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
The swelling characteristics and engineering performance of expansive soils are primarily governed by their clay mineralogy; however, mineralogical identification based on a single method may be insufficient for natural clays composed of multiple clay minerals together with non-clay constituents. This study aims to determine the mineralogy of a natural expansive clay from the Çubuk district of Ankara, Türkiye, using an integrated set of direct and indirect methods, and to demonstrate the limitations of relying on a single technique while proposing a practical combination of tests for more reliable mineralogical identification. Direct analyses included X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX), while indirect indicators comprised methylene blue adsorption, Atterberg limits, clay fraction content (<2 μm) and activity. The results show that the Çubuk clay contains a significant smectitic (montmorillonitic) component together with non-clay minerals such as quartz and calcite. Methylene blue results indicate high cation exchange capacity and specific surface area, and SEM–EDX spectra support the presence of interlayer cations consistent with a smectite-dominant clay fraction exhibiting illite-smectite characteristics. The results highlight the advantage of a multi-method approach and provide a practical framework for more robust mineralogical characterization.