Capillary water absorption characteristics of some Cappadocian ignimbrites and the role of capillarity on their deterioration

Abstract

Cappadocia stands out as one of the most important regions in Turkey for its natural, historical, and cultural heritages. The region is under the influence of wetting and drying and freezing and thawing weathering processes, which are largely controlled by the water content. Water migrates through rock pores via different processes, such as capillary water absorption, which is one of the most common ways observed in the Cappadocia region. In this study, a research program consisting mainly of laboratory studies was carried out to investigate the capillary water absorption characteristics of ignimbrites, which are the host rocks of many natural and historical heritage structures in Cappadocia. Accordingly, XRD analyses, mercury porosimeter, and capillary water absorption tests were performed. The pore size distribution, which is a function of welding degree, controls the capillary water absorption process of ignimbrites. Particularly, ignimbrites that have a uniform pore size distribution of around 5–10 μm reveal higher capillary water absorption potential. Ignimbrites have a considerable and variable potential in terms of capillarity, and the capillarity plays a major role on the deterioration and decomposition of many of the historical and natural heritage structures in the Cappadocia region.