Utilization of industrial and agricultural by-products in blended cement mortars – creating an effort of circular economy in Indian cement industry

India stands in second place as a manufacturer of cement in the world, accounting for over 8 % of the worldwide mounted capacity until the end of the year 2018. It is estimated that the production of the cement will touch 550 Mt by the year 2020 and will reach more than 600 Mt by 2025. Up to the year 2015, the total emissions of CO2 from cement sector in India have touched the level of around 150 Mt in comparison to an amount of 52 Mt emitted in the year 2013. This amount of generation has been projected to increase by 9 %–10 % annually up to the year 2025. The boosting demand for construction activities results in incessant growth of the sector along with alarming environmental consequences and non-sustainability in the cement industry. Utilization of the various industrial and agricultural by-products as an alternative form of binder in the cement can reduce the perilous environmental impacts and their practice will further offer an auxiliary solution in fetching the concept of circular economy in the surging cement industry. Blended types of cement made up of industrial and agricultural by-products can successfully replace the limestone-based clinkers. The adoption of such practice could offer a significant reduction in CO2 emissions approximately by 20 %. On the other hand, the abundant generation and the efficient utilization of industrial and agricultural wastes primarily having binder qualities similar to that of cement has set up a new challenge in the construction industry. Next to a review of industrial and agricultural clinker substitutes, this contribution estimates the impact of these clinker substitutes on CO2 reduction in the Indian cement industry up to 2050