Arun Shukla, President and Director, JK Lakshmi Cement, elucidates how supplementary cementitious materials (SCMs) are evolving as an indispensable route toward a sustainable future.
Construction activities and large-scale infrastructure development form the bedrock of economic progress. At present, growing population, rapid urbanisation, commercialisation and increasing residential needs are catapulting demand for commercial, residential and industrial buildings. However, the alarming rise in environmental concerns including climate change and pollution have made it critical for the construction sector to prioritise sustainability for a greener and better future. As per reports, the construction sector accounts for 23 per cent of air pollution, 40 per cent of drinking water pollutants, and 50 per cent of landfill wastes. At this juncture, it thus becomes crucial to find the right balance between development and sustainability, and innovative concepts like green buildings have emerged as a practical solution for it.
While green buildings carry tremendous potential to reduce environmental impact, they further bring additional advantages such as improving energy efficiency, promoting better air quality and healthier ecosystems, efficient resource utilisation and minimising wastage. According to data, green buildings can reduce energy consumption by 20-30 per cent, water usage by 30-50 per cent, and significantly reduce waste generation through extensive recycling. Considering the rise in construction activities to meet the current and future demands, development of green building is both beneficial and a necessity.
Since utilising sustainable materials is key to promote green construction practices, the use of supplementary cementitious materials (SCMs) can take the benefits of green buildings to another level. SCMs are not only environmentally friendly, but are a potent solution to inch closer to sustainable development and decarbonisation goals as well.
Understanding SCMs
Simply put, SCMs are materials or substances which are added to concrete to make it more environmentally friendly, durable and enhance its performance. They not only improve the strength of concrete but bring huge sustainability-related benefits as they require lower energy for production and support in reducing greenhouse gas emissions. As per estimates, for every tonne of clinker replaced by SCMs, the carbon dioxide emissions are reduced by around 0.8 tonnes.
It is noteworthy that SCMs are mostly by-products coming out from various industries, which makes them highly beneficial in terms of utilising waste materials and promoting efficient resource utilisation for both environmental and economic gains. The various types of SCMs that are used to enhance concrete’s performance and properties include fly ash which is a by-product of coal combustion in power plants. Fly ash contains silica and alumina and improves concrete workability, reducing heat generation and increasing long-term strength.
Another SCM is silica fume, which is a fine material produced during silicon metal and alloy production. It effectively strengthens concrete and reduces permeability. Moreover, natural pozzolans like volcanic ash, calcined clay are great options to enhance concrete workability, durability, and strength. Metakaolin, a calcined clay, is also beneficial in improving concrete’s properties and durability, particularly reducing permeability and increasing chemical resistance. Similarly, natural zeolites, minerals with a porous structure, enhance concrete workability and durability. These various kinds of SCMs in addition to offering diverse benefits, allow the construction industry to utilise by-products and waste materials and reduce the need for high energy-intensive cement manufacturing, promoting sustainability.
Sustainability advantages
The demand for buildings is increasing rapidly and thus constructing green buildings is a solution to ensure this demand is met in an environmentally friendly manner. While green buildings definitely make it possible to create spaces which promote cleaner and healthier environments, the use of SCMs ensure their sustainability related advantages are multiplied, environmental impacts are reduced, resources are efficiently utilised, energy demand is lowered, and overall well-being is achieved.
For instance, use of SCMs in construction supports greenhouse gases reduction. The production of SCMs require less energy as compared to traditional cement and support in reducing carbon emission and use of fossil fuels to combat environmental challenges like depleting natural resources, climate change and air pollution.
The other advantage of using SCM is enhancing the durability of concrete. Mixing SCMs can make concrete long-lasting and efficient, promoting conservation of resources. By using durable concrete with SCMs during construction of green buildings, it becomes possible to reduce the need for frequent repairs, replacements, and extend the lifespan of buildings. For instance, materials such as fly ash and slag carry the potential to mitigate alkali-silica reactions which often lead to formation of cracks in buildings and impact concrete’s durability. By incorporating SCMs, it becomes possible to avoid the damaging effects and achieve stronger and structurally sound buildings with longer lifespans.
Most importantly, use of SCMs helps the construction industry to adopt responsible sourcing of materials, efficient utilisation of by-products and promote waste minimisation for sustainable development. Since most of these materials are by-products of various industries, integrating them
in construction not only supports efficient use of resources but further prevents them from ending up in landfills as waste, minimising their harmful environmental impact and potential health hazards to achieve healthier ecosystems for current and
coming generations.
In the current period where construction activities are growing constantly to satiate residential and commercial demands, green buildings developed using SCMs are a great way to promote sustainability. SCMs in green buildings are not only environmentally friendly but bring a host of advantages, which are essential to build a greener, healthier and better future for all.