Abstract

Characterization of Aksaray-Guzelyurt clays in the Central Anatolian region were carried out and the clay minerals used in the building stones and their effects were evaluated. The clay samples taken from Guzelyurt area located to the southeast of the city of Aksaray were investigated employing the spectroscopic methods. The differential thermal analysis (DTA) and the thermogravimetric analysis (TGA) measurements have been carried out for determinations of thermal behaviour of the clay samples. First, the Fourier Transform Infrared (FTIR) spectra of the standard clay minerals-“The World Source Clay Minerals” such as illite (IMt-1; Silver Hill, Montana, USA), illite-smectite mixed layer (ISMt-1; Mancos Shale, Ord.), beidellite (SBId-1; Idoha, USA), kaolinite (KGa-1; Washington Country, Georgia, USA), chlorite (ripidolite, CCa-1; Flagstaff Hill, El Dorado Country, California, USA), nontronite (NAu-2; Uleynine, South Australia), montmorillonite (SCa-3; Otay, San Diego Country California, USA) were obtained. Then the spectra of anhydrite, gypsum, illite+quartz+feldspar, quartz+feldspar were recorded together with the standard clays. Then, the mineral phases included in samples taken from Aksaray-Guzelyurt area were identified by comparing their FTIR spectra with those of the standard clay minerals and X-ray Diffraction (XRD) patterns. It was found that the clay samples include quartz, illite (T-O-T), kaolinite, amorf silica and they have T-O (Tetrahedral-Octahedral) or O-T (Octahedral-Tetrahedral) structure. The main clay mineral in the samples is kaolinite. Clays constitute the majority of occurring minerals that occur as the alteration product of building stones. The carbonate rocks using in various constructions are mainly composed of calcite. In general, dolomite, silica and clay minerals accompany this mineral. The clay type and their characteristics that result in shortening life of buildings are first examined and then visual deteriorations occurring associated with exteriors have been discussed. Common use of the carbonate rocks containing clays such as marl as building stones quarried from the Guzelyurt area increases such incidences at the regional scale.

Key words: Central Anatolia, FTIR, clay, illite, smectite.