ABSTRACT
Mortar samples from three historical monuments in the southern Indian state of Tamil Nadu were evaluated using X-ray diffraction, Scanning electron microscopy, and Fourier transform infrared spectroscopy for their mineralogical and morphological characteristics. The results show that the lime used is of a non-hydraulic type. Additionally, several studies were performed on lab based mortars to access the parameters of compatibility to check the suitability of different renders. From the testing of lab based samples, it was observed that, for studying the compatibility of repair mortar, parameters like modulus of elasticity and capillarity coefficient play a significant role as they help to judge the rigidity and porosity of the mortar. While cement mortar proves to be very rigid for old masonry substrate, plain lime mortar is very porous. For all properties studied, the lime mortar mix with organic additives gave optimum results.
