Stępień Piotr, Spychał Edyta, Nartowska Edyta
Faculty of Civil Engineering and Architecture, Kielce University of Technology, Al. Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland.
Faculty of Environmental Engineering, Geomatics and Renewable Energy, Kielce University of Technology, Al. Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland.
Materials (Basel). 2024 Aug 14;17(16):4049. doi: 10.3390/ma17164049.
This research investigates the phase change behavior of water within the pore space of Devonian carbonate rock samples using Differential Scanning Calorimetry (DSC) across a temperature range of -80 to 0 °C. This study focuses on dolomite and limestone samples, all with porosities below 3%, an area not extensively covered in previous literature. Significant endothermic effects were observed at temperatures below -2 °C, challenging conventional understanding. The study reveals that the latent heat of phase change in these systems can exceed 334.2 J/g, the known value for bulk water, indicating unique thermodynamic properties of water in confined spaces. For the dolomite rock sample, observed endothermic heat effects below -2 °C were 23.5% and 26.7% of total phase change energy. The cumulative pore volume calculated using the thermoporometry method was found to be higher than expected from water occupancy alone, independent of assumptions about the thickness of the adsorbed unfreezable water layer or pore shape (spherical or cylindrical). This research provides novel insights into unfrozen water content calculations, significantly enhancing frost durability assessments and the geoengineering industry.
本研究利用差示扫描量热法（DSC），在-80至0°C的温度范围内，研究了泥盆纪碳酸盐岩样品孔隙空间内水的相变行为。本研究聚焦于白云岩和石灰岩样品，其孔隙率均低于3%，这是一个在以往文献中未被广泛研究的领域。在低于-2°C的温度下观察到了显著的吸热效应，这对传统认识提出了挑战。研究表明，这些系统中相变的潜热可能超过334.2 J/g（这是 bulk water 的已知值），这表明受限空间内水具有独特的热力学性质。对于白云岩样品，在低于-2°C时观察到的吸热热效应分别占总相变能量的23.5%和26.7%。使用热孔率测定法计算出的累积孔隙体积高于仅根据水占据情况预期的值，且与关于吸附的不可冻水层厚度或孔隙形状（球形或圆柱形）的假设无关。本研究为未冻水含量计算提供了新的见解，显著改进了冻融耐久性评估和岩土工程行业。
