Abstract:

Field survey, systematic sampling and laboratory tests were conducted to study the weathering mechanism of earthen architecture taking the Jiaohe Relics site, Xinjiang, China for example. Particle size analysis, X-ray diffraction and chemical analysis of soluble salts illustrate that surface crusts are characterized by finer particles and lower soluble salts contents compared with the host soil. Temperature monitoring by IR thermography camera and thermal sensors shows that thin crusted layers response greatly and quickly to the environmental temperature change. It is concluded that the local saturation and slurry film generation due to rainfall are mainly responsible for the formation of surface crusts; and the crust will be subsequently detached by wind erosion and expansion-contraction induced by the change of temperature. Surface crusted layer prevents the wall from weathering to some degree at its earlier formation stage but tend to accelerate the deterioration of the earthen architectures in the long term considering that Jiaohe site suffer from strong sandstorm and strict weather condition.

Key words: earthen architecture, weathering, crust, detachment