Water absorption and P-wave velocity changes during freeze-thaw weathering process of crosscut travertine rocks

摘要

The Turkish travertine is widely used in the domestic and foreign construction industry as slabs and tiles. In this study, the travertine samples were obtained from four different quarries located in the part of southwestern Turkey. Mineralogical and petrographic properties of the travertine rocks were studied using a polarizing optical microscope and SEM. The laboratory tests (mechanical and physical properties, capillary water absorption, freeze-thaw (F-T) process, P-wave velocity) were performed according to Technical Specification European Standard (TS EN) standards. The pore size distribution was determined by means of high-pressure mercury porosimetry (MIP). The most of the pores (>80%) of tested travertine have a pore access diameter of <0.1 mu m. Some engineering properties of the rock are severely affected by F-T cycles such as ultrasonic P-wave velocities, water absorption weight and strength. The porosity of the travertine presents significantly higher values after the cycles of freeze-thaw, which also leads to the increase in the absorption by immersion. The water absorption method showed that water absorption weight of the specimens varied from 0.32 to 0.88%, after the 25. period. The freeze and thaw effects of the samples which were tested after exposing to water were measured at a certain time. The obtained dry, saturated and frozen P-wave velocities were examined by the changes of four travertine samples. P-wave velocity increase is in the range of 4.99-5.97% for tested travertine rocks. These studies explain that the P-wave velocity changes in freezing travertine exclusively due to changing velocities of pore infill, i.e., water, air and ice.