ORIGINAL PAPER Effect of salt crystallization on weathering of pyroclastic rocks from Cappadocia, Turkey Hakan Özşen 1 & Ali Bozdağ 2 & İsmail İnce 2 Received: 1 August 2016 /Accepted: 14 May 2017 /Published online: 13 June 2017 # Saudi Society for Geosciences 2017 Abstract Salt crystallization is the most significant factor in the degradation of the natural stones used in cultural and his- torical structures. Stones decay partially or fully as a result of this exposure. This study is the investigation of the degrada- tion of historical monuments (underground cities and semi- underground settlements) carved in pyroclastic rocks in Cappadocian Region which takes part in World Cultural Heritage List. Samples of pyroclastic rocks were collected from six different quarries in Cappadocia, Turkey. To under- stand the contribution of salt crystallization to this weathering, dry weight loss (DWL) tests were performed on these sam- ples. To investigate the correlations between salt crystalliza- tion and other rock properties, porosity, water absorption, ul- trasonic velocity, uniaxial compressive strength, Brazilian ten- sile strength, and point load index were also measured. During the SC process of weathering, the results showed that porosity and water absorption increased for all the samples whereas ultrasonic velocity, uniaxial compressive strength, tensile strength, and point load index values decreased. Evaluation of the data obtained from these tests showed very high loga- rithmic correlations between the dry weight loss values and the mechanical properties. Keywords Dry weight loss (DWL) . Pyroclastic . Index and strength tests . Building stones . Cappadocia Province Introduction First samples of cultural monuments are mostly built in pyro- clastic rocks (i.e., Cappadocia region, Turkey; Kilistra ancient city, Turkey; Midas Monument, Turkey; Kandovan, Iran; Norchia Necropoli, Italy; Vardzia Monastery Complex, Georgia; etc.). Building materials of Cultural Heritage are exposed to many damaging conditions such as time and environmental degradation (Fitzner 1994; Camuffo 1995). Salt crystallization (SC) process is one of the most important factors in the deg- radation of rocks (Doehne and Price 2010) and main factor in SC is absorption of salt into the rock (Killip and Cheetham 1984; Pitzurra et al. 2003; Sandrolini and Franzoni 2006; Bozdağ 2013; Korkanç 2013). Building stones are exposed to salt over time by rain and salts deposited in the rock’ s pores. The crystallization of waterborne salts in porous materials can generate pressures inside the pores high enough to exceed the elastic limit of the material. This kind of degradation process produces extremely ag- gressive damage, such as loss of material, flaking, exfoliation and, in some cases, even the complete disaggregation of the material (Ruffolo et al. 2013). Degradations related to salt crystallization are studied by many researchers (Topal and Sözmen 2003; Ludovico-Marques and Chastre 2012; La Russa et al. 2013, 2015, 2017; Barone et al. 2015; Özvan et al. 2015; Bozdağ et al. 2016; Temraz and Khallaf 2016). The most common method to determine the effects in building stones related to SC process is dry weight loss (DWL) test. The DWL changes due to SC in building stones have been studied by many researchers (Ulusoy 2007; Zedef et al. 2007, 2011; Zedef and Unal 2010; Bozdağ 2013). In this study, DWL related to SC process is investigated on the building stones from Cappadocian region of Turkey, which is known by former and recent structures produced in * Hakan Özşen hozsen@selcuk.edu.tr 1 Department of Mining Engineering, Selçuk University, Konya, Turkey 2 Department of Geology Engineering, Selçuk University, Konya, Turkey Arab J Geosci (2017) 10: 258 DOI 10.1007/s12517-017-3027-8