HYDERABAD: Through the centuries, the composition of lime plaster, a type of plaster widely used for construction or restoration of archaeological structures, has undergone a change. This is because it is hard to figure out the materials that went into the creation of this mortar, apart from there being a difference in quality of raw materials over time.
As a result, archaeologists and conservation architects often find compatibility issues between the original lime plaster used in the construction of a structure and the new lime plaster while carrying out restoration works, leading to formation of cracks in the structure.
To mitigate this problem, researchers from National Institute of Technology (NIT), Warangal, have embarked on a long-term study of the microstructure of lime plaster used in the masonry of heritage monuments such as the Ramappa Temple in Warangal, so that they can figure out what kind of raw materials were used to make the plaster. They aim to figure out the recipe and create a new mortar using those materials.
The research, underway for the past one-and-a-half years, is being undertaken by research student Nikhil Kumar Degloorkar and professor Rathish Kumar Pancharathi, both from National Institute of Technology Warangal.
Speaking to Express, Pancharathi said, “For restoration purposes, we have to understand what kind of mortar was used for construction. In order to understand that, we have to do a complete microstructure characterisation. Through our research on Ramappa Temple, we have identified several materials that were used to make that mortar. We are trying to create a new mortar from those materials.”
Kumar and Pancharathi’s research includes the study of various types of mortar from structures such as Warangal Fort and Ramappa Temple. Recently, they published the findings from their study on the above-mentioned structures in a report titled ‘Investigation of microstructure characterisation of mortars from 800-year-old heritage structures in southern part of India.”
The study, accessed by Express, shows that Kumar and Pancharathi found the presence of calcite (a common rock-forming mineral) and quartz (a hard, crystalline mineral composed of silicon and oxygen atoms) through various techniques such as X-ray diffraction analysis. Through X-ray fluorescence spectroscopy, they also found that the mortar did not contain magnesium oxide, a compound that is found in modern day mortars.