Travertine has found preference and when filled, it can be much utilized for external cladding material for the buildings. Thermal properties of the stone may be changed depend on the pores closed by filling material on the surface. The aim of this paper is to assess thermal properties of filled and unfilled travertine stones after exposure to freezing-thawing and thermal shock cycles. For this purpose, thermal properties and physical parameters of the stones were determined at every 25 freezing-thawing and thermal shock cycles until totally 75 cycles were completed. Results indicated that the increasing number of freezing-thawing and thermal shock cycles caused a meaningful decrease in thermal conductivity parallel to decrease in unit volume weight and P-wave velocity for unfilled travertine in comparison to filled travertine. The results emphasize that the importance of surface finishing techniques and the filled travertines are more durable than unfilled travertines under extreme temperature changes.
Travertines have been widely used as construction and building materials from as early as prehistoric times to recent times because of their wide variety of textures and colours (Pedley 2009, Urosevic et al. 2010). Travertine is considered as durable stone although wetting-drying, freezing-thawing, salt crystallization and air pollution effects may cause weathering and black crust formation on façades especially in urban areas (Sindraba et al. 2004, Torok 2006a, 2008). These environmental factors may have a crucial role on the permeability and hydrothermal behavior of exposed building components.
The heat insulation of buildings is a very important subject with respect to energy saving. Heating/cooling systems are very important to save energy, especially in under-developed countries with limited resources. There are various materials used as thermal insulators and applied as building coating. The use of natural stone with low thermal conductivity in buildings could provide energy savings and can be characterized by thermal conductivity (Yasar et al. 2008). Natural stones are one of those materials with high prefer ability due to their decorative view. A review of earlier investigations reveals that rock type, porosity, P-wave velocity and moisture content have the most effective factors on the thermal conductivity of rocks (Incropera & Dewitt 1990, Hasan 1999, Canakci et al. 2007).