Preliminary study on the impact of severe heat waves on dolostone weathering: implications for deterioration of carbonate rock-hewn heritage in SE China

Climate change has led to many catastrophic events. In summer 2022, southern China witnessed a record-breaking heat wave. For example, Hangzhou, the capital city of Zhejiang Province (China), experienced a 2-month period of extreme hot weather. Rock outcrops exposed to strong solar radiation and high temperatures can experience rapid increase in temperature and repeated thermal cycles, which can affect the fabric and physical/mechanical properties of the rock and threaten the preservation of rock-hewn heritage. China has many examples of carbonate rock-hewn heritage with high historical and artistic value. Most are found in subtropical coastal areas with high heat and humidity, and where they might experience extreme high-intensity heat events in the future. Therefore, to study the impact of heat wave events on such examples of cultural heritage, a realistic heat wave aging test was performed in this study using samples of dolostone freshly quarried from near the West Lake Cultural Landscape of Hangzhou world heritage site. The nature of deterioration of the dolostone was evaluated using the capillary water absorption coefficient, surface hardness, and splitting tensile strength. The pore system of the dolostone samples was determined using the nitrogen adsorption method. Experimental results showed that the mechanical properties of the dolostone decreased moderately, while the water absorption capacity and porosity (micropores–mesopores) increased, indicating that high-temperature heating affects the physical and mechanical properties of dolostone to a certain extent. On the basis of the rapid rate of global warming and the increasingly frequent occurrence of extreme high-temperature events in China, the influence of thermal cycling on rock-hewn heritage deserves further attention.