The company says the product can replace natural aggregates and reduce the environmental impact from quarrying natural stone.
NTPC says its research project on the production of the geo-polymer coarse aggregate has met the Indian Standards statutory requirements and has been confirmed by the National Council for Cement and Building Materials (NCCBM).
India’s demand for aggregates is nearly 2,000 million tonnes per year and NPTC says its new fly ash-based product will help in meeting the requirement.
Around 258 million tonnes of ash is produced in India by coal-fired thermal power plants each year. Of this around 78% of the ash is utilised, with the remainder ending in ash dykes. NTPC says its new coarse aggregates can enable more than 90% of ash to be utilised.
NTPC says geo-polymer aggregates are suitable for extensive use in the construction industry. It adds: "These aggregates are extremely environmentally-friendly and do not require any cement for application in concrete where the fly ash-based geo-polymer mortar acts as the binding agent. The geo-polymer aggregates will help in reducing carbon emissions and have great potential for reduction of water consumption."
