Harnessing the past: Vibration analysis of organic additives in ancient plasters for sustainable building solutions

Abstract

This study investigates plant-based organic additives and grains used in ancient earthen plasters from the caves of Karla, Bhaja, Pitalkhora, Ellora, and Aurangabad in Maharashtra, India, highlighting their relevance for sustainable modern construction. Stereo microscopy, FTIR spectrophotometry, and phytochemical analysis identified rice husk, millet, wheat, Chenopodium album, Paspalum, barnyard millet, foxtail millet, and Fumaria seeds as key organic components. Starch grain analysis confirmed the presence of wheat, millet, and mung bean starches, while polarized light microscopy revealed distinctive birefringence patterns, such as the Maltese cross. FTIR analysis of solvent extractions identified natural compounds, including starches, gums, proteins, oils, waxes, and tree resins. These organic additives, especially rice husk, prevalent in Karla, Bhaja, and Pitalkhora samples, and the balanced composition of hemp fibers, seeds, and gums in Ellora samples, contributed significantly to the strength and durability of the plasters. The use of beeswax and tree resins as natural binders further underscores the ingenuity of these ancient techniques. This research not only highlights the botanical diversity in ancient construction but also draws critical connections to modern sustainable practices. The carbon-negative potential of these materials, combined with their renewability and resilience, aligns closely with contemporary green building strategies, offering inspiration for eco-friendly construction rooted in traditional Indian architecture.