Knowing from the past – Ingredients and technology of ancient mortar used in Vadakumnathan temple, Tirussur, Kerala, India

In the present study, lime mortar samples from the restoration site of Vadakumnathan temple, Kerala, India have been analyzed. Samples from three different locations of the temple such as ancient wall, gopuram and arch have been taken. Traditional methods such as chemical analysis, acid loss analysis and organic test were conducted on mortar samples. Modern instrumental techniques such as electronic particle size distribution, X-ray Diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX), Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and Infrared Spectroscopy (FT-IR) were employed in the study. The binder used in the mortar is calcium high with 30% of clay mineral. A binder to aggregate ratio in the range of 1:1.5–2.5 has been established from acid loss analysis. Particle of the aggregate are mostly silt in nature, hence nominal sand would have been grinded to reduce the particle size and to induce pozzolanic reaction. The presence of carbohydrate, protein and fats are identified by organic test that are in agreement with FT-IR analysis and TGA.