Ancient Indian techniques for sustainable and environmentally friendly decorative earthen plasters of Karla and Bhaja Caves, India

• Published in: Materials today : proceedings Vol. 32; pp. 536 - 543
• Main Authors: Dighe, B., Singh, M.R., Pokharia, Anil K.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2020
• Subjects: Antioxidant; Careya arborea; Earthen plaster; Eco-friendly; Sustainable; Traditional material; Earthen plaster; Traditional material; Antioxidant; Sustainable; Careya arborea; Eco-friendly
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2020.02.040

Analytical identification using phytochemical test, light and scanning electron microscopy revealed the presence of Careya arborea stem fibres and rice husk mixed as an organic additive in the historic plaster. In the coastal regions of Western Ghats, India, C. arborea stem fibre having antioxidant, antimicrobial and termite resistance properties helped the survival of earthen plasters even in unfavourable climatic condition (immense rainfall region). Moreover, the utilization of agro-waste material such as rice husk played a role in decreasing density, imparting plasticity, durability and reducing cracks in the plaster. On comparison of earthen plaster composition of Karla caves to that of Buddhist caves of Bhaja situated just about 10 km away and belong to the same period, it is noticed that the Karla caves plaster has shown higher survival rate. This may be due to the inclusion of C. arborea plant stem fibres in earthen plaster of Karla caves. Bhaja caves plaster contains rice husk and Paspalum grains (a weed growing along rice plant) as organic additive, which together played a role in imparting properties as discussed above but have not provided antifungal and insecticidal properties to the plaster leading to its deterioration. This study helps in understanding that the ancient technicians implemented cost effective, environmentally convenient, and upgraded traditional technologies with locally available material in the construction of Karla caves earthen plaster by utilizing an appropriate mixing of vegetable fibres, clay, sand and agricultural waste.