Concrete

Economic Implications of Using SCMs

Published

3 years ago

November 20, 2023

admin

ICR analyses how the integration of supplementary cementitious materials (SCM) and the strategies thereof has catalysed the cement industry’s economic landscape, fostering streamlined processes and enhanced resource utilisation, ultimately shaping a more resilient and profitable sector within India’s economy.

The way to look at any cementitious material in modern times would be to look at the carbon intensity inherent in it in terms of CO2 emissions, such as clinker, which forms the basis for making cement. After grinding the clinker (95 per cent) with gypsum and some correctives (together at 5 per cent), its emission intensity is 849-868 kg per tonne of output. Thus, when you produce ordinary Portland cement (OPC), which contains only clinker as the base cementitious material, the emission intensity is the highest at 750-860 kg of cement output. The lower end of the band is reserved for those who use the best technology that improves thermal efficiency and electrical efficiency.
Now, OPC could be the best suited for giving the early strength of cement measured by the compressive strength in MPa. Whether you take a 3-day or 7-day or 28-day strength, OPC would remain at the highest when you compare with any other form of cement that supplements clinker in the OPC with other cementitious materials like fly ash, slag, silica fume, natural pozzolans – such as calcined clays, shale and metakaolin, sugarcane bagass ash (SCBA) or rice husk ash (RHA).
The purpose of using supplementary cementitious material is two-fold:

Economic
Environmental
The way to deal with this subject would be to look at the life cycle assessment of each of these and compute the impact. To make matters simple one may first look at the carbon intensity in each in terms of emissions and attach an appropriate environmental cost to it. Let us look at some of these numbers:
Portland Pozzolana Cement (PPC) uses a mix of 60-65 per cent clinker, 5 per cent gypsum and 25-30 per cent fly ash thus taking the overall emission to an average 700 kg per tonne of cement. Efforts have been always to look at ways of maximising fly ash and PPC specifications allow for even 35 per cent fly ash to meet the compressive strength guidelines. However, we must note that compressive strength will be lower for 3 days, 7 days and 28 days for PPC when compared with OPC by at least 8-10 per cent. If one considers the cost of fly ash that is replacing clinker, the economic impact is huge as the cost of the former is a fraction of the latter.

Economic Implications
To compute the economic benefits of fly ash in PPC there are two important factors to be considered. The grinding units that are the final delivery points of cement units must be logistically located such that the cost of fly ash could be minimised. But this is a network optimisation question and the optimisation would entail outbound logistics cost of cement as well. Most advanced economies, India included, have looked at fly ash as an economic agent that not only turns waste into wealth but also reduces environmental impact of cement emissions (850 kg to 700 kg per tonne). The reduction in the landed cost of fly ash would further improve the economics through better logistics cost optimisation and mode-mix improvements. In recent times freight charges on rail in India for fly ash have been reduced to move fly ash over longer distances.
The environmental impact over long distance haulage of fly ash thus could be brought down
using rail as the mode, a crucial factor for the life cycle assessment.
The wider economic implication could be seen in the alternative deployment of a waste that was put to landfill is now an economic alternative to clinker. Some fly ash producers like NTPC or TATA Power or Adani Power, who together produce more than 100 million tonnes of fly ash per year, could be powerful actors to sway economic balance. Fly ash brick manufacturers who operate in the smaller concentrated networks, mostly SMEs, could be the next contenders in the value balance.
Slag based cement, uses 50 per cent clinker and 45 per cent slag and 5 per cent gypsum on an average. It is the next best example of SCM making a huge difference to the economic as well as environmental impact. By replacing a large amount of clinker, slag-based cement thus makes the emission intensity of cement come down to less than 500 kg per tonne of cement. This when looked at the back of the cost of slag vis-à-vis clinker, which it replaces in the cement, the economic implication is huge. The total production of blast furnace slag is growing, despite its environmental impact and it makes an economic case for GGBS.
However, blast furnace slag or the copper smelter slag, as inputs mixed together, is not free and must compete as commodities with clinker. But game theoretic approaches to price negotiations have fructified into either contracts that are short or medium term tenured (a sharp departure from the past) or pure spot contracts through auctions, that could be well mired in quasi-collusion dynamics of all kinds (in the past). Slag producers seeing an economic opportunity (as opposed to the environmental impact they face otherwise) have mostly experimented with a mix of spot and contracting strategy. The slag benefit in cement over clinker could be in the range of 30-40 per cent looking at the range of cost dynamics that would also include transportation cost by rail.
When one adds the CO2 emission impact benefit, fly ash and slag make a stunning case.

Exploring Other Options
The next most talked about SCMs are silica fumes and natural pozzolans, but their use has been limited in most parts of the world due to economic evaluations, including logistics cost. However, this economics could be lopsided in Europe where fly ash is hardly available and slag could be following suit. Natural pozzolans like calcined clay and metakaolin are therefore in news today, especially in Europe. In India, for example, they could be traded at cement cost, whereas in Europe they could well be lower than the clinker cost.
Utilisation of fly ash in cement has been improving in India but it is still far from the developed world numbers. The old wet fly ash lying in ponds and the dry lying in ash mounds could together be in excess of 100 million tonnes. While the vertical roller mills (VRM) technologies offer great benefits overall ball mills in grinding for absorption of wet fly ash, some innovative methods to use wet fly ash without adding to cost have been developed by some. Similarly, those having a logistics advantage towards a mix of fly ash and slag have settled for composite cement that could use a blend of fly ash and slag in their grinding mix. These could offer negotiating leverage while settling contracts in fly ash and slag.
At the end, to weigh the environmental impact in concrete, which uses a mix of sand, gravel, cement and water, one must see the equation differently: in a one cubic metre of concrete, using 14 per cent cement in the mix, the CO2 emission would be of the order of 410 kg/cubic metre compared to 290 kg per cubic using 30 per cent fly ash in PPC.

–Procyon Mukherjee

Up Next

Use of SCMs in Green Buildings

Don't Miss

Future Potential Materials

Concrete

Cement Makers Reaffirm Commitment to Sustainable Growth

Published

2 days ago

June 5, 2026

admin

World Environment Day spotlight on innovation and circularity

On World Environment Day, the Indian cement industry reiterated its commitment to supporting India’s climate ambitions through sustainable manufacturing, resource efficiency and the adoption of cleaner technologies.

The Cement Manufacturers’ Association (CMA) said the sector remains aligned with the Government of India’s Net Zero commitments and is accelerating efforts to reduce its environmental footprint while supporting the country’s infrastructure and development agenda.

Parth Jindal, President, CMA and Managing Director, JSW Cement, said the industry is increasingly adopting cleaner technologies, improving energy efficiency and expanding the use of alternative fuels and raw materials. He also highlighted the growing importance of circular economy practices, where industrial by-products and waste streams from one sector are utilised as resources in another.

“The Indian Cement Industry is aligned to the Government’s commitments on carbon mitigation and is accelerating the adoption of cleaner technologies, resource efficiency and circular economy practices while actively exploring the potential of Carbon Capture, Utilisation and Storage (CCUS) as a critical pathway for deep decarbonisation,” said Jindal.

He added that coprocessing industrial waste and by-products helps conserve natural resources, reduce disposal requirements and lower the environmental footprint across multiple sectors.

According to Jindal, sustainability is no longer limited to manufacturing processes but is increasingly influencing investment decisions, innovation strategies and long-term growth plans within the industry.

Echoing similar views, Dr Raghavpat Singhania, Vice President, CMA and Managing Director, JK Cement, said sustainable development extends beyond emissions reduction and must also focus on responsible resource utilisation and waste minimisation.

“Sustainability in the built environment cannot be measured by emissions alone. It is equally about how efficiently we use resources, how effectively we minimise waste and how responsibly we create the infrastructure that will serve future generations,” said Singhania.

He noted that the cement industry is advancing its sustainability agenda through greater resource efficiency, increased circularity, technological innovation and continuous improvements in manufacturing practices. As a key contributor to India’s infrastructure development, the sector has a critical role to play in balancing economic growth with environmental responsibility.

On the occasion of World Environment Day, industry leaders reaffirmed their commitment to supporting India’s climate goals while delivering the materials required for resilient, durable and sustainable infrastructure.

Concrete

Building a Greener Future Together

Published

3 days ago

June 4, 2026

admin

Environmental sustainability requires immediate action, not just long-term commitments and discussions. Recycling, circular economy practices, and technology-driven waste management can help industries reduce environmental impact while supporting sustainable growth.

Author: Jignesh Kundaria, Director and CEO, Fornnax Technology

World Environment Day serves as an important reminder that environmental sustainability can no longer remain confined to discussions, reports, or long-term commitments. The environmental challenges facing the world today demand immediate, measurable, and collective action. Across industries and communities, waste generation continues to outpace our ability to process it responsibly, placing increasing pressure on ecosystems, natural resources, public health, and the well-being of future generations.

One of the most significant shifts required today is a change in how society perceives waste. Rather than being viewed as a material to be discarded, waste must be recognised as a valuable resource that can contribute to both economic growth and environmental protection when managed through the right technologies and systems. This mindset forms the foundation of the circular economy model that countries across the world are increasingly adopting to reduce landfill dependence, recover valuable materials, and create more sustainable industrial ecosystems.

India has made meaningful progress in strengthening awareness around sustainability, recycling, and environmental responsibility over the past decade. Significant efforts are being made to formalise the recycling sector through improved infrastructure, technology adoption, policy implementation, and broader stakeholder participation. These developments are creating a stronger foundation for responsible waste management and resource recovery across the country.

However, achieving long-term environmental impact requires collaboration from all stakeholders. Industries, policymakers, technology providers, and communities must work together with greater accountability to strengthen recycling ecosystems, encourage responsible waste management practices, and create sustainable outcomes through consistent execution rather than temporary interventions.

As someone closely associated with the recycling industry, I firmly believe that technology will play a decisive role in addressing future environmental challenges. Advanced recycling systems have the potential to recover valuable resources, reduce pollution, minimise landfill burdens, and conserve energy, creating a more sustainable future for generations to come. This belief is deeply reflected in Fornnax’s motto, “Committed to Create a Green Future,” which embodies our commitment to building long-term environmental value through innovation and responsible action.

At the same time, technology alone cannot deliver meaningful change. Real progress requires intent, awareness, participation, and a shared sense of responsibility. Sustainable development can only be achieved when innovation is supported by collective action and a genuine commitment to environmental stewardship.

On this World Environment Day, let us move beyond conversations and take meaningful steps towards creating a cleaner, greener, and more sustainable planet. By embracing innovation, strengthening recycling ecosystems, and acting responsibly today, we can create lasting environmental impact and secure a better future for generations to come.

Concrete

JK Lakshmi Advances LC3 Cement Expansion

Company highlights commercial production and research partnerships

Published

6 days ago

June 1, 2026

admin

The meeting reviewed progress in limestone calcined clay cement (LC3) technology and its commercial adoption in India’s cement sector, focusing on low-carbon alternatives to conventional binders. JK Lakshmi Cement noted that limestone calcined clay cement can reduce carbon dioxide emissions by up to 40 per cent compared with conventional cement and said this reduction supports industry decarbonisation. The company highlighted that it was among the first two cement manufacturers in India to move LC3 into commercial production after the Bureau of Indian Standards approved the technology as a cement standard.

Vinita Singhania said the transition of LC3 from research to commercial production reflected collaboration between industry, academia and international institutions. Maya Tissafi acknowledged JK Lakshmi Cement’s role in advancing LC3 adoption in India and its contribution in taking the technology from laboratory trials to commercial implementation. Both representatives underlined the growing relevance of sustainable construction materials as India expands infrastructure and urban development.

The meeting explored continued collaboration with Swiss research institutions such as EPFL, EMPA and ETH Zurich alongside Indian academic partners and development organisations. JK Lakshmi Cement has been associated with the LC3 initiative since 2014 and worked with EPFL, IIT Delhi, IIT Madras, Development Alternatives and Technology and Action for Rural Advancement. The company conducted one of the earliest industrial trials of LC3 and recently announced commercial production of Green Pro LC3 cement from its Jaykaypuram plant in Rajasthan.

India remains the world’s second-largest cement producer and expansion of infrastructure, urbanisation and housing demand continue to support long-term sector growth, increasing interest in low-carbon technologies. The company reported an annual turnover of more than Rupees (Rs) 60 bn and current cement capacity of about 18 million (mn) tonnes (t) per annum, with a target of reaching 30 million (mn) tonnes (t) by 2030. Apart from grey cement, the company also makes ready-mix concrete, gypsum plaster, wall putty, primers, adhesives and fly ash blocks, and both sides concluded on the need for continued collaboration to develop sustainable construction solutions.