Navrátilová P., Greif V., Maľa M. & Palou M.-T., 2018: Preliminary results on linear expansion force change in freeze-thaw cycles as indicator of frost resistance. Acta Geologica Slovaca, 10, 1, 35–43.

Preliminary results on linear expansion force change in freeze-thaw cycles as indicator of frost resistance

Patrícia Navrátilová¹, Vladimír Greif¹, Martin Maľa¹ & Martin-Tchingnabé Palou²

¹Department of Engineering Geology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava, Slovakia; npatricianavratilova2015@gmail.com
²Department of Materials and Rheology, Institute of Construction and Architecture, Slovak Academy of Sciences, Dúbravská cesta 9, 845 03 Bratislava 45; martin.palou@savba.sk

Abstract

Frost resistance of rocks is important parameter in assessment of rock decay due to exogenous processes. Current testing methods rely on thermal loading of saturated samples in climatic chamber for extended period of time and consequent detection of drop in ultrasonic velocity speed or uniaxial compressive strength (UCS). Presented study aims at developing faster method of frost resistance detection by measuring linear expansion force generated during freeze-thaw cycling on fully saturated samples. Preliminary results on andesite samples taken from two sites in middle Slovakia suggest that higher volume of micropores influences frost resistance of samples, causing lower frost resistance to thermal loading of fully saturated samples. Further, cycle testing in modified thermodilatometer VLAP04 suggest the possibility of detection of higher amount of micropores by linear expansion force (LEFC) detection during initial cycles of testing, potentially allowing for faster detection of frost resistance in harder rocks compared to conventional methods using climatic chamber. Moreover, frost resistance parameter k₂ (STN 72 1800) appears to be not suitable for harder rocks due to high variance in UCS and destructive character of these tests.

Key words: andesite, linear expansion force change, freeze-thaw cycles, porosity, frost resistance, ultrasonic velocity, uniaxial compressive strength

Manuscript received: 2017-11-21

Revised version accepted: 2018-06-19