Mohak Gupta, Assistant Program Director – Resource Efficiency and Circular Economy, Development Alternatives
In light of growing pressures from indiscriminate resource extraction and consumption, mounting heaps of various kinds of wastes, and the looming challenge of climate change, circular economy approaches now offer sustainable alternatives for the construction industry. While on the surface, the circular economy model seems to solve waste management issues, at its core, it promulgates a systemic shift in how we produce and consume by decoupling economic growth from resource extraction.
Transitions in fundamental materialsIn the construction sector of India, with building materials accounting for almost 40 per cent of the carbon footprint of a building in the form of embodied energy, technology transitions in the fundamental materials such as cement, steel, sand, and coarse aggregates can go a long way in enhancing circularity and decarbonisation benefits. For instance, the adoption of national standards by the BIS for Limestone Clay Calcined Cement (LC3), a new type of cement with a 30 per cent carbon reduction in the production process and the potential to use secondary resources, is a welcome step.
There is a significant push to transition to innovative building materials in India, but it is far from the needed scale. For instance, while there is a shift from polluting burnt clay bricks to alternatives such as fly ash bricks, AAC blocks, and other precast products, their uptake remains mostly restricted to larger urban agglomerations and varies significantly across states based on the respective regulatory and business landscapes.
Other industrial wastes, such as red mud and blast furnace slag, are finding use in geopolymers and aggregates. City governments riddled with huge quantities of construction and demolition (C&D) debris are looking for solutions; however, the implementation remains painfully slow, with only a handful of cities that can boast of functional C&D waste processing facilities. Experiments on utilising different wastes in construction are widespread, with waste thermocol used as insulation, plastic waste used to make bricks and roads, or as refuse-derived fuel (RDF) in cement-making, and textile waste finding utility in acoustic panels and insulation boards.