Interface Between Grey Brick and Lime Mortar: Chemical Reactions and Resulting Microstructure

Abstract

In recent years, the use of lime mortar has garnered a lot of attention due to its sustainability and its ability to renew old architecture. However, there has been a lack of research on the adhesion between lime mortar and grey brick. To clarify the adhesion of lime mortar and grey brick, we comprehensively investigated a representative sample, which was constructed between 1366 and 1386 CE, using various techniques. The results of our analysis indicated that the calcium from the lime mortar diffused from the surface of the lime mortar through the grey brick matrix in an approximately 1.5 mm-thick layer. This physical process led to a decrease in the porosity of the grey brick’s appearance, providing a historical explanation for the long-term durability of the partial structure of the adhesive as a load-bearing element.