# Damage Characteristics of Thermally Deteriorated Carbonate Rocks: A Review
## 5 Thermal Deterioration of Porous Network
#### Heat Transport Properties
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Material Properties** & **Major Findings** & **Reference** \\ \hline Permeability & They noticed that, at a low temperature, crystalline limestone showed slight variations in its permeability. Moreover, the thermal cracking of limestone at a temperature above 400 \({}^{\circ}\)C produced an appreciable increment in its permeability. & [115] \\ \hline Porosity \& Permeability & They studied the temperature effect on the hydraulic and poroelastic properties of limestone. They found that the permeability of limestone was increased by 3\% and 8\% at the temperatures of 150 \({}^{\circ}\)C and 250 \({}^{\circ}\)C, respectively. & [116] \\ \hline P-wave Velocity & They investigated the thermo-physical behavior of limestones at varying temperatures. They noticed slight variations in P-wave velocities at a temperature of 150 \({}^{\circ}\)C and a linearly decreasing trend by 55\% at 500 \({}^{\circ}\)C. & [13] \\ \hline P-wave Velocity & He studied thermal effects on the physical properties of carbonate rocks. At the initial temperature (i.e., 200 \({}^{\circ}\)C), only 4\% depreciation was recorded in the P-wave velocity. However, at a temperature of 600 \({}^{\circ}\)C, due to the brittle–ductile transformation, its value reduced to 36\%. & [12] \\ \hline Porosity & They investigated the thermal damage effect on the porosity of air-cooled and water-cooled limestone specimens. They found that, at 200 \({}^{\circ}\)C, both limestone samples showed a very similar increase in porosity (i.e., 1–1.5\%). At the temperature of 300 \({}^{\circ}\)C, air-cooled and water-cooled limestone samples showed a 3\% and 6\% rise in porosity, respectively. On further increase in temperature of 600 \({}^{\circ}\)C, water-cooled limestone samples demonstrated slight variations in their porosity, whereas air-cooled limestone samples followed a linear increasing trend in porosity by 11\%. & [83] \\ \hline Porosity & They observed no significant variations in the total porosity of carbonate rocks at ambient temperature. However, at 800 \({}^{\circ}\)C, ductile behavior considerably changed the porosity by 13\%. & [117] \\ \hline Permeability & They found a reduction in the permeability of pre-heated fractured carbonate rocks with a slight rise in temperature (i.e., 60 \({}^{\circ}\)C). The obvious reason for this behavior is that, at a low temperature, rock dilates to enhance stiffness, which ultimately reduces permeability. On the other hand, at higher temperatures, fluid transport properties improve on account of thermal cracking and brittle–ductile transformation. & [118] \\ \hline Porosity & They evaluated the porosity of carbonate rocks under different conditions. For porous dolostone, they found that the temperature effect was larger than the pressure effect and the rate of dissolution was inversely proportional to temperature. & [119] \\ \hline Permeability & They observed no changes in the permeability of limestone at low temperature and then recorded an increase in permeability by 2\%, 10\%, and 126\% at the temperatures of 600 \({}^{\circ}\)C, 700 \({}^{\circ}\)C, and 800 \({}^{\circ}\)C, respectively. Beyond the temperature of 700 \({}^{\circ}\)C, limestone lost its integrity, which is why a sharp increase was noted in its permeability. & [106] \\ \hline P-wave Velocity & They observed that thermal exploitation reduces the stiffness of porous rocks, turns them into a more compressible state, and hinders wave propagation by limiting their quality. & [90] \\ \hline P-wave Velocity & They studied the coupling effect of high temperature and liquid nitrogen quenching on the physical characteristics of limestones. They found an appreciable reduction in P-wave velocities by 47\% and 88\% at a temperature of 400 \({}^{\circ}\)C and 600 \({}^{\circ}\)C, respectively. & [105] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Summary of major findings regarding the variations in physical properties of the thermally damaged carbonate rocks.