Maľa M., Greif V., Ondrášik M. & Macková A., 2021: Changes in pore characteristics of travertines from Spišské Podhradie after repeated freeze-thaw cycles. Acta Geologica Slovaca, 13, 1, 119–128.

Changes in pore characteristics of travertines from Spišské Podhradie after repeated freeze-thaw cycles

Martin Maľa¹, Vladimír Greif¹, Martin Ondrášik² & Anna Macková¹

¹Department of Engineering Geology, Hydrogeology and Applied Environmental Geophysics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava, Slovakia
²Department of Geotechnics, Faculty of Civil Engineering, Slovak University of Technology in Bratislava, Radlinského 11, 810 05 Bratislava, Slovakia

Abstract

This study aims to understand the effect of frost weathering of travertines from Spišské Podhradie in Slovakia. The application of travertine as a natural building and facing stone shows a gradually increasing trend in construction sector around the world. Travertines are commonly seen in tile sizes as façade material, wall cladding or flooring and are naturally exposed to the freeze–thaw processes. Methods of frost damage assessment in rocks are commonly based on parameters acquired mainly by destructive testing of samples, such as the uniaxial compressive strength test or Young’s modulus test. In the presented research, a nondestructive method taking advantage of selected petrophysical properties compared before and after 100 freeze-thaw (F-T) cycles, as well as recorded length change behavior and temperature development by a specially- constructed thermodilatometer (VLAP 04) with two induced linear variable differential transformer sensors (HIRT- LVDT) on vacuum-saturated samples has been conducted. Results demonstrate that travertine from Spišské Podhradie is quite heterogeneous in term of petrophysical properties. This heterogeneity can significantly affect the nature and intensity of the processes which take place during the ice crystallization within the pore space of the rock. While crystallization pressures in the macropores and the hydraulic pressure induced by the migration of water towards the advancing freeze front cause the specimen to expand, they are not sufficient to overcome the reduction of pore pressures in micro and mesopores and thus the total contraction of the specimen occurs after 100 freeze-thaw (F-T) cycles. The changes in the microstructure of the pore space of the travertine from Spišské Podhradie are not significant and so we can state that this travertine is a resistant material to the effects of frost weathering.

Key words: travertine, frost weathering, petrophysical properties, ice crystallization, crystallization pressure, frost shrinking, freeze-thaw

Manuscript received: 2021-04-23

Revised version accepted: 2021-05-25