Evaluation of the impacts of severe heatwaves on carbonate rock deterioration in Hangzhou, China: Implications for urban rock- hewn heritage conservation

Abstract A record-breaking heatwave affected southern parts of China in 2022 summer causing arid conditions in places. Hangzhou, the capital of the Zhejiang province, China, experienced two-month hot weather. Human beings were severely affected, and the abundant carbonate rock-hewn heritages in the city were challenged. An outdoor heatwave erosion test was carried out on the local carbonate rock samples to evaluate the heatwave's impact on these stone heritages. The nature of deterioration was determined using the water absorption coefficient, surface hardness, splitting tensile strength and pore structures. After the 15-day heatwave erosion test, the water uptake ability of the carbonate rock increases combining with growth in micropores. Meanwhile, the mechanical strength of the rock shows a distinct decline, indicating a breakdown interior of the stone. Therefore, the study results show that the heatwave can significantly damage the carbonate rock-hewn heritages and may become one of the critical threats to them due to China's relatively high warming rate.