Ancient architectural pathology of blue bricks and brick carvings in Northwest China: Example from the White Temple Tower

Rising damp is one of the main problems affecting historical masonry structures worldwide, as it affects the appearance of heritage architecture and reduces strength. In this study, to reproduce the pathologies as much as possible and explain the mechanism, the aging test was set up with the climate data (temperature, humidity, etc.) derived from the real environment in nature at the location of the White Temple Tower, which was the object of this study. The tests mimicked the temperature, humidity, and types of salt solutions as closely as possible. Unlike the traditional aging test (producing specimens in accordance with some standards), two samples of blue brick carvings and blue brick cubes were used for the test. The results show that brick carvings suffered more severe surface degradation than brick cubes under various circumstances. Brick specimens' mechanical characteristics, such as wave velocity and compressive strength, were greatly diminished, and there was a fluctuating trend in surface hardness and color difference. The data indicate a size effect on the weathering between brick carvings and brick cubes, with the former displaying a faster rate of weathering under identical conditions. The experiment successfully simulates some of the phenomena observed in the field and provides an idea for studying the weathering of brick artifacts.