REC «Mekhanobr-tekhnika» (Russia):

Vaisberg L. A., Corresponding Member of the Russian Academy of Sciences, Doctor of Engineering Sciences, Professor, Scientific Advisor of the Company

Petrozavodsk State University (Russia):

Kameneva E. E., Ph. D. in Engineering Sciences, Associate Professor, Head of Laboratory, elena.kameneva@mail.ru

An effect of cyclic freezing and thawing on rocks microstructure was studied with respect to types of rock materials, conventionally used in crushed stone production — granite and gabbro. Samples structure was studied with application of X-ray microcomputed tomography by means of «SkyScan-1172» apparatus. The following parameters of initial pore space structure were determined in mineral samples: volume, specific surface area, size, shape, connectivity between pores and separate minerals, pore spatial distribution in samples structure and in individual tomographic slices. Then the samples were soaked in water at room temperature for 20 hours, and after that subjected to alternate freezing to –20 °С and thawing in accordance with the rock freeze-thaw resistance standard test procedure. Tomographic imaging was repeated following 15 freezing-thawing cycles. It was established that with cyclic freezing and thawing of rocks, pore space structure changes not only in surface layer, but also in total volume of rock material. Total porosity is increased through formation of new subsurface porosity. Plastic deformations, caused in rock volume by action of alternating-sign temperature loads, occur owing to crystallization of chemically non-bound water, and also due to the difference in values of linear and volume coefficients of rock-forming minerals thermal expansion.

The work was performed with the financial support from the Federal Targeted Programme «Research and development in the trends of priority growth areas of the science and technology sector of the Russian Federation for 2014–2020», the grant No. 14.574.21.0108.

1. Dobrynin V. M., Vendelshteyn B. Yu., Kozhevnikov D. A. Petrofizika (Petrophysics). Moscow, Nedra, 1991, 368 p.
2. Romm Ye. S. Strukturnyye modeli porovogo prostranstva gornykh porod (Structural models of pore space of rocks). Leningrad, Nedra, 1985, 240 p.
3. Myasnikova O. V. Influence of mineral composition and physical properties of rocks on their durability. Sovremennyye metody tekhnologicheskoy mineralogii v protsessakh kompleksnoy i glubokoy pererabotki mineralnogo syrya. Materialy mezhdunarodnogo soveshchaniya «Plaksinskiye chteniya—2012» (Modern methods of technological mineralogy in the process of complex and deep processing of mineral raw materials. Proceedings of the International meeting «Plaksin's readings—2012»). Petrozavodsk, Karelian Research Centre of the Russian Academy of Sciences, 2012, pp. 102–104.
4. Kurilko A. S. Eksperimentalnyye issledovaniya vliyaniya tsiklov zamorazhivaniya—ottaivaniya na fiziko-mekanicheskiye svoystva gornykh porod (Experimental studies of freeze—thaw cycles influence on the physical and mechanical properties of rocks). Yakutsk, Yakut subsidiary of the Publishing house of the Siberian Branch of the RAS, 2004, 154 p.
5. Vaisberg L. A., Kameneva E. E. X-ray computed tomography in the study of physico-mechanical properties of rocks. Gornyi Zhurnal = Mining Journal, 2014, No. 9, pp. 85–89.
6. Skamnitskaya L. S., Kameneva Ye. Ye. Study of gas-liquid inclusions in minerals from the posions of processing mineralogy. Obogashchenie Rud, 2005, No. 2, pp. 31–36.
7. Karnakov A. V., Yezhov Ya. V., Marchuk S. D., Donskoy V. I., Shcherbachenko L. A. Anomalous properties of absorbed water in complex silicates. Fizika Tverdogo Tela = Physics of the Solid State, 2006, Vol. 48, Iss. 11, pp. 1946–1948.
8. Shcherbachenko L. A., Donskoy V. I., Karnakov V. A., Komarov Ye. V. et al. Structural phase transitions in micro-sized water films in nonequilibrium heterogeneous systems. Vestnik Buryatskogo Gosudarstvennogo Universiteta = Bulletin of the Buryat State University, 2012, No. 3, pp. 202–207.