The Use of Thermoporometry in the Study of Frost Resistance of Rocks

From an engineering point of view, it is important to know the factors influencing the frost resistance of rocks with porosity above 2% due to their different frost resistance. The article focused on frost durability research using the thermoporometry method (TMP) and the assessment of water phase transition in the pore spaces of selected rocks. For this purpose, the differential scanning calorimetry method (DSC) was used with the adoption of an original algorithm for eliminating the thermal inertia of the measurement system. The results of the DSC method were supplemented with the results of pore size distribution using the mercury intrusion porosimetry method (MIP) and standard rock frost resistance tests. Based on the research carried out using the thermoporometry method, it was confirmed that the ability of water to freeze in the temperature range from -5 °C to -20 °C was important, as well as the ability of rocks to increase the degree of water saturation during freeze-thaw cycles. Based on calorimetric tests combined with thermoporometry, in the case of non-frost-resistant rocks, a significant (dominant) share of pores with a radius of under 10 nm (amounting to over 0.008 cm³/cm³) was found. Pore connections in the water freezing process do not influence the investigated rocks' frost resistance.