Abdul Wahab Khan
Panaji : In what could be a promising solution to managing Goa’s environmental pollution, researchers from the department of civil engineering at the Goa College of Engineering have developed high performance, eco-friendly building blocks made entirely from iron ore mining waste.
These building blocks can be used in the construction sector. The study, published in ‘Nature Environment and Pollution Technology,’ offers an answer to Goa’s challenge of managing over 7.7 million tonnes of iron ore tailings (IOTs) generated in the past two decades.
The study states that while some tailings are presently used for backfilling, the majority are stored in tailings storage facilities (TSFs), posing a long-term risk to the surrounding water resources, ecosystems and land use.
To address this, the lead researchers, S A Kakodkar and Ulhas G Sawaiker, investigated the feasibility of using IOTs in concrete block production with a two-fold goal of reducing the environmental footprint of mining and creating a cost-effective, durable building material.
The report states, “The optimal mix design, achieving the highest compressive strength, utilises 15% cement, 65% ground granulated blast-furnace slag (GGBS), 10% fly ash and lime and 100% IOTs as fine aggregate with 100% basaltic aggregates.”
These composite blocks have demonstrated good structural integrity, reaching compressive strength of 10.91 N/mm² (Newton per square millimetre) after seven days and 15.92 N/mm² after 28 days – well above the requirements of Indian standards for masonry units.
The report states that the cement content was slashed by 85% and replaced with industrial byproducts like GGBS, fly ash and lime – materials often considered waste themselves. The IOTs fully replaced conventional sand, reducing reliance on riverbed sand mining.
The blocks achieved a density of 2.20 g/cm³ (grams per cubic centimetre) and demonstrated good water resistance with an average absorption rate of just 4.64%, well within the regulatory limits. Additionally, the blocks showed no signs of efflorescence – the unwanted deposition of soluble salts on surfaces that can compromise structural integrity and aesthetics. The research team subjected the blocks to rigorous testing protocols outlined in Indian standards.
The project was supported by the Department of Science and Technology and Waste Management, Government of Goa.
