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Revival of small scale cement manufacturing

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The availability of most of the AFR is limited or scattered which may not be economically viable for use in most of the large cement plants because of logistics, quantity, preparation and technical issues, says Dr KN Bhattacharjee.

The availability of most of the AFR is limited or scattered, which may not be economically viable for use in most of the large cement plants because of logistics, quantity, preparation and technical issues. This is a great roadblock for the effective use of AFR. However if an industry can find means to utilise its own by-product or waste in its own premises or nearby then it will be a win- win situation for all. Cement manufacturing process is a very appropriate process to recycle many industrial and agricultural wastes. The black meal process of vertical shaft kiln technology is a proven technology in China and India and can serve as a very good outlet for consuming AFR in the vicinity of industries generating the waste in small quantities.

This will also help in reducing environmental pollution. The author has carried out numerous plant scale trials with various industrial and agricultural wastes in VSK plants in India with reasonable success and feels that it may be worthwhile to go backward technology-wise to improve India’s usage of AFR. With the recognition of performance-based cements in most of the standards of world, composite cements are to gain ground and many alternate materials mainly industrial wastes can find profitable use again in small-sized cement plants.

The vertical shaft kiln (VSK) technology is an old technology of Portland Cement manufacture and even the modern versions have almost phased out from India mainly because of economics of scale and taxation issues. In China, still 30 per cent of its cement production comes from shaft kiln plants. The VSK process technology is still a workable proposition for use of wastes available in limited quantities. Also by virtue of the simple process a plethora of process issues associated with modern pre-heater, pre-calciner rotary kiln system are eradicated while using AFR. Plant scale trials with many wastes have shown improvement in VSK clinker quality and better productivity from the kilns. Also it is possible to add many wastes in small quantities directly to VSK clinker to produce high performing composite cements. Although the plan sounds to be reverse engineering but sometimes an old concept can regain its past glory due to changing national needs and environmental issues.

The modern vertical shaft kiln technology is technically sound and institutes like National Council of Cement and Building Materials (NCCBM) and the then Regional Research Laboratory (RRL), Jorhat had done a commendable work in modernising the technology in India. Also the village-based Saboo technology created a stir in India in the 80s when they brought cement manufacturing under the umbrella of small scale industry. During that period, the objective was to increase production as India was cement deficit and VSK technology was a partial answer to quickly bridge the gap between demand and supply. In the hilly terrain of North East, it is still a viable proposition to use scattered small limestone deposits in the midst of logistical challenges.

The advantages and disadvantages of black meal process of vertical shaft kiln technology:

Advantages:

  • Small scale cement production and still suitable in hilly terrains having limestone deposits for local distribution of cement.
  • Energy efficient process: Specific heat consumption is in the range 600 to 650 Kcal/kg of clinker. Specific power consumption is in the range 0f 60 to 70 Kwh/tonne OPC although authentic figures are not available. Since drying, pre-heating, calcining, burning and cooling are integrated in the same vessel, heat losses due to convection and radiation is much reduced.
  • Porous VSK clinker is much easier to grind thus cement grinding power requirement is less.
  • Very low refractory consumption as kiln is stationery and low abrasion as material flow is vertically downward with slow speed.
  • Vast scope of using AFR available in smaller quantities is the major advantage. Some alternate waste materials can act as flux or mineraliser. Mineralising ions can increase the rate of reaction in burning zone leading to complete burning in burning zone.
  • Thus the technology offers avenue not only in the use of wastes but also utilise the waste in improving burnability by stabilising phases at lower temperatures.
  • recirculation of obnoxious gases and materials which ensures smooth operation and higher productivity.
  • Due a constant bed of wet green nodules above the calcining zone the green nodules bed acts as an effective filter to arrest all dust particles. No additional gas cleaning device is required.
  • Since fuel is inter-ground with raw materials elaborate arrangement of fuel preparation and firing is eliminated
  • Very effective and controlled flow of material through flat grate using variable frequency drive (VFD). This helps to position the burning zone constantly at the same level.
  • Relatively simple machines to operate and maintain.
  • Gestation period of starting a new plant is very low.
  • No highly skilled manpower is required and local folk/plant staff can be easily trained for operations.
  • Possible to manufacture a variety of clinkers and thereafter produce various kinds of low cost Portland cements.
  • Very little chance of cold air in-leakages. Diversion of combustion air during clinker discharge has been ably dealt by either triple air locking arrangement or material block tube in the modern VSKs.
  • Since each nodule has its independent fuel system significantly higher temperatures are not achieved leading to no issues of NOx.

Disadvantages:

  • Viability can be at stake due to taxation policies and lower scale of operation. However if Government gives tax rebates on use of AFR the plants can be viable. Also it is possible to reduce cost of production by using low cost or free of cost non- conventional materials and waste fuels available locally. Maybe the savings can be shared with customers.
  • Quality issues: Many believe that VSK clinker cannot be at par with modern rotary plant clinker. In this respect a few conflicting issues are prevalent. It is true that using the same raw materials and fuel the modern rotary clinker will be better performing especially the later age compressive strengths and soundness of cements produced. However the soft burnt nature of the VSK clinker opens up possibilities of addressing customer requirements of good early age compressive strength and early setting in the case of PPC and PSC. The author has found that early age compressive strengths and setting can be matched with modern plants while making PPC with a maximum of 30 per cent fly ash absorption. The Black meal process is capable of producing sound clinkers with less than 1.5 per cent free lime and 45 per cent C3S component. The author’s experience in few VSK plants in Jodhpur-Rajasthan region supports this viewpoint. Experiences with various limestone in Northern India and Bhutan reveals that the technology cannot tolerate high magnesia limestone primarily due to the absence of rapid cooling arrangement but adding certain industrial wastes with mineralising minor constituents gives amazing results in reducing or mitigating this deleterious effect.
  • Consistency of clinker: Consistency does get affected if the raw mix is not well homogenised and nodulisation is not controlled. However these can be easily solved by using good homogenisation and blending techniques. Nodulisation can be automated to yield nodules of good strength. In some cases nodule strength can be improved by double nodulisation. Various industrial wastes like bagasse from sugar industry have been found to improve nodule strength together with bonus addition of heat value. Waste oils can be added at this stage to give very good results.
  • Heat difference between the central and peripheral charge especially in the large dia kilns of 100 TPD per day can be a matter of concern in some cases depending of raw materials and fuels used. The 50 tonne/day Saboo shaft kiln design was found to very efficient in this respect. Crust formations were found to be minimal. Dustry clinker due to beta to gamma conversion of C2S is prevalent in few cases but can be eliminated by stabilisation of phases even with the inherent disadvantage of rapid or quench cooling.

Plant scale trials using various alternate materials and fuels:

Use of pond ash, bottom ash and boiler fired rice husk ash in a 50 TPD VSK plant in Kanpur Dehat, Uttar Pradesh: Both bottom and pond ash were procured from Panki Thermal power plant and were used as components of raw mix separately as a source of Silica and Alumina by partial replacement of plastic clay by 15 to 20 per cent. There was drop in free lime from 2.2 per cent to 1.8 per cent and the dust content in clinker reduced drastically. There was increase of 1.5 to 2.0 MPa in 3 days and 3 MPa in 28days compressive strength of 43 grade OPC. The pond and bottom ash had substantial carbon particles (LOI- 15 to 20 per cent) which added some heat value and perhaps the reactivity of the raw mix increased by the presence of some amount of reactive alumino-silicates. Indirect effects noticed was smooth kiln operations with a slight increase of production from the 50 TPD VSK. Pond ash which is generally wet can be added directly during nodulisation if a dosing arrangement is designed to avoid the drying operation. Boiler fired Rice Husk was tried in the same plant which gave very good results in improving clinker quality. The material was black in colour with LOI around 10 per cent indicating unburnt carbon which must have supplemented the heat input. It was possible to add rice husk as it is but plant scale trial was not attempted with the apprehension that the husk fibres may not give a homozenised mix in the existing raw grinding arrangement.
Use of Phosphorus furnace slag, alkali bypass dust and bag house dust from a Calcium Carbide plant: All these materials were tried with a contention to capitalise mineralising effect from the wastes due to some minor constituents or the presence of reactive silica or Alumina. Even granulated blast furnace slag (GBFS) was also tried. Improvements in kiln productivity and quality was noticed of clinker in most of the cases. In VSK operation any measure which goes to ensure completion of the reactions in the short burning zone will definitely go in improving clinker quality and smooth kiln operations. Appropriate raw mix fineness with correct proportioning of waste materials and fuels, homogenisation hold the key to success.
Additions of alternate waste materials with VSK clinker to make composite cements The future of cement making is composite cements. This not will helps to use some industrial or agricultural wastes in the final product but also help to improve performance of cements and reduce the carbon footprint. In many cases it can lead to low cost cements together with better performance.

Significant improvement was observed when 5 per cent bag house dust from a calcium carbide plant was added in a quaternary mix of 60 per cent Granulated Blast Furnace slag (GBFS) and 3 per cent gypsum using VSK clinker. Initial setting time was reduced from 180 minutes to 40 minutes when compared with plain control sample of PSC. There was an improvement of 2 MPa at 3 days and 28 days compressive strength was more or less the same. Quaternary blends using Alkali bypass dust and 60 to 70 per cent GBFS , gypsum and VSK clinker also performed well in terms of faster setting and improvement of early age compressive strength. Similar results were obtained while using brick kiln ash and calcined clay Pozzolana in dosages of 15 to 20 per cent while making PPC mixes using VSK clinker.

Thus VSK clinker can act as a performance enhancer for early setting and early age compressive strength in presence of high dosage GBFS containing PSC cements and fly ash/CCP based Pozzolanic cements. Hydration studies have revealed that the soft burnt VSK clinker releases soft burnt lime at a faster rate in the early ages leading to higher quantity hydration products both with GBFS and Pozzolana.

Conclusion
The author was associated with VSK plants for six years while doing his Ph.D. His doctoral work is mainly associated with hydration studies of composite cements and VSK clinker doped with ions coming from various industrial and agricultural wastes. He feels that the black meal process using modern vertical shaft kiln technology can be a viable proposition to use localised waste materials available in limited quantities. The process simplicity of the Black Meal process opens up immense potential for use of wastes (both agricultural and Industrial) with improved cement performance in many cases. Waste generating plants can have captive VSK plants or sub let this activity to local entrepreneurs. All performance enhancements have been validated by actual hydration studies which is available with the author for anyone who is interested. This has been a part of the author’s doctoral work. The author feels that for India till we incorporate large scale AFR facilities catering to large cement plants the VSK plants can be revived mainly for use of localised AFR as the project cost and gestation period from concept to commissioning is very low.

Acknowledgement
The author is grateful to AKS University administration for allowing to publish this paper.

About the author
Prof (Dr) KN Bhattacharjee
has 37 years experience in the global cement industry. He has worked with all process technologies of cement manufacture and has done considerable work on use of AFR in mini-cement plants. His Ph.D thesis is in applied cement chemistry and his findings helped many mini-cement plants in India to improve their profitability during the late 80s. He has publications in reputed international and national journals like Cement and Concrete Research, ZKG International, Silicate Industrials, Transactions of Indian Ceramic Society, etc. After his retirement in 2016 from Dangote-Africa, he is teaching cement technology to B.Tech students in AKS University, Satna. Dr KNB has worked with ACC in India, two plants in Oman, Lafarge Canada and Dangote, Africa.

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Nuvoco Vistas launches Limla cement plant, expands Gujarat footprint

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Nuvoco Vistas opens a 2 MMTPA grinding unit at Limla, entering Gujarat and advancing its target of 35 MMTPA capacity by FY 2028.

Surat (Gujarat)

Nuvoco Vistas Corporation Ltd, a part of Nirma Group and one of India’s leading building materials company, has inaugurated the Limla Cement Plant in Surat (Gujarat), one of Vadraj Cement Limited’s (VCL) principal manufacturing facilities. The commissioning represents a key milestone in Nuvoco’s acquisition and restoration of VCL, while supporting the company’s expansion across the Western Indian cement market.

Vadraj Cement Limited is a subsidiary of Nuvoco Vistas Corporation Limited and has installed cement capacity of 6 MMTPA across its assets. The Limla inauguration therefore represents the first operational step in the acquired platform’s wider revival, while the Kutch facilities provide clinker supply, mineral security and coastal logistics support for the western business.

Nuvoco completed its acquisition of Vadraj Cement Limited, then under the Corporate Insolvency Resolution Process, after paying a consideration of Rs 1,800 crore in June 2025. VCL’s asset portfolio comprises a clinker unit at Kutch and a grinding unit at Limla in Surat. It also includes high-quality captive limestone reserves and a captive jetty at Kutch, supporting more efficient logistics. Following the takeover, Nuvoco began an extensive programme of restoration, refurbishment and expansion at both locations, leading to the commissioning of the Limla plant.

The Limla Cement Plant is expected to support a phased increase in sales volumes across Gujarat. It will also help Nuvoco supply neighbouring markets in Western Maharashtra and release cement capacity from its northern plants, which can consequently be redirected towards markets in North India. The plant will manufacture a full portfolio comprising Ordinary Portland Cement, Portland Slag Cement, Portland Pozzolana Cement and Portland Composite Cement. It will additionally produce the complete Nuvoco Duraguard range, including the premium Nuvoco Duraguard Microfibre product. The acquisition is also expected to generate operational synergies with Nuvoco’s existing plants at Nimbol and Chittorgarh in Rajasthan, improving logistics optimisation and market reach across important regional markets.

The grinding unit at the Limla Cement Plant was completed ahead of schedule, with 2 MMTPA of capacity now inaugurated to expand Nuvoco’s operating scale and customer reach. After Vadraj Cement’s assets become fully operational, plants in North and West India are expected to account for nearly 40 per cent of Nuvoco’s total cement capacity. This will broaden the company’s manufacturing network, strengthen access to high-growth markets and support its plan to increase consolidated cement capacity to 35 MMTPA by FY 2028, reinforcing its longer-term growth strategy.

Commenting on the development, Jayakumar Krishnaswamy, Managing Director, Nuvoco Vistas Corp Ltd, said: “The inauguration of the Limla Grinding Unit in Surat is an important milestone in Nuvoco’s growth journey and demonstrates our commitment to disciplined, value-accretive expansion. Gujarat is strategically significant for Nuvoco, with substantial opportunities arising from infrastructure investment, industrial growth, rapid urbanisation and continuing demand from the housing and construction sectors. The facility strengthens our regional footprint, improves operational flexibility and increases our ability to serve customers across northern and western markets with greater reliability and efficiency.”

He added: “Through the Vadraj acquisition, we have refurbished and restarted a strategically important asset, returning it to operations in record time through strong execution and collaboration between teams. The achievement demonstrates our ability to create value from acquired assets, fulfil our commitments and retain the confidence of stakeholders. It also highlights the strength of our project delivery capabilities and our continued focus on building sustainable, profitable growth over the long term.”

Nuvoco Vistas Corporation Limited is a building materials company whose vision is to build a safer, smarter and more sustainable world. It is among the leading players in East India and has a significant presence across North and West India. Nuvoco began operations in 2014 with a greenfield cement plant at Nimbol, Rajasthan. It later acquired Lafarge India Limited, which had entered India in 1999, followed by Emami Cement Limited in 2020 and Vadraj Cement Limited in April 2025. The company has also announced an expansion in eastern India through a new grinding mill at the Arasmeta Cement Plant, supported by several debottlenecking programmes involving equipment upgrades, process improvements and internal capacity initiatives. These developments place Nuvoco on track to achieve total cement capacity of approximately 35 MMTPA. The company reported total income of Rs 11,362 crore in FY 2025-26, reflecting its continuing growth trajectory.

Nuvoco operates a diversified portfolio across three segments: Cement, Ready-Mix Concrete and Modern Building Materials. Its cement portfolio includes Concreto, Duraguard, Double Bull, PSC, Nirmax and Infracem, covering Ordinary Portland Cement, Portland Slag Cement, Portland Pozzolana Cement and Portland Composite Cement. Its pan-India RMX business provides value-added products under Concreto for performance concrete, Artiste for decorative concrete, InstaMix for ready-to-use bagged concrete, X-Con covering M20 to M60 grades, and Ecodure for specialised green concrete. Nuvoco has supplied materials to projects including the Mumbai-Ahmedabad Bullet Train, Birsa Munda Hockey Stadium in Rourkela, Aquatic Gallery at Science City in Ahmedabad, and metro railway projects in Delhi, Jaipur, Noida and Mumbai.

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Green Construction Through Cement Innovation

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Indian Cement Review (ICR) and Fuller Technologies brought industry, policy and technology leaders together to discuss how cement innovation can drive green construction at scale, writes Rakesh Rao.

India is building at a pace few countries can match. Highways, airports, housing, logistics parks, industrial corridors and urban infrastructure are reshaping the country’s economic geography. But beneath this growth story lies a difficult question: can India continue to build at scale without locking itself into a high-carbon future?

That question formed the core of an online panel discussion titled “Driving Green Construction Through Cement Innovation”, organised by Indian Cement Review (ICR) in association with Fuller Technologies as the Presenting Partner on June 25, 2026. The webinar brought together experts from cement technology, R&D, global industry platforms, building performance policy and international development cooperation to examine how low-carbon cement and material innovation can accelerate India’s green construction transition.

The discussion came at a crucial time. India has committed to achieving net-zero emissions by 2070 and reducing the carbon intensity of its economy by 45 per cent by 2030. At the same time, the country’s construction sector is expanding rapidly, driven by urbanisation, infrastructure development, housing demand and industrial growth. Cement, as one of the most widely used construction materials, sits at the heart of this transition. It is indispensable to development, but also central to the challenge of reducing embodied carbon in buildings and infrastructure.

Moderated by Nitika Krishan, Senior Urban Infrastructure and Sustainable Policy Consultant, the panel featured:

  • Kiranmai Sanagavarapu, Director, Low Carbon Solutions, Fuller Technologies;
  • Dr Hemantkumar Aiyer, VP and Head R&D, Nuvoco Vistas Corp Ltd;
  • Devika Wattal, Innovation Lead, Global Cement and Concrete Association (GCCA);
  • Dr Sunita Purushottam, MD, GBPN India (Global Buildings Performance Network); and
  • Vaibhav Rathi, Senior Technical Advisor, GIZ (the German Agency for International Cooperation)

Setting the tone for the discussion, Nitika Krishan underlined the scale of the challenge before the sector. “The question before us is no longer whether we build, but how we build sustainably,” she said. She pointed out that construction accounts for nearly 40 per cent of global energy-related carbon emissions when both operational and embodied carbon are considered. Cement production, she added, remains one of the hardest industrial processes to decarbonise.

For India, this is not merely an environmental issue. It is a development issue, a competitiveness issue and increasingly, a market issue. As one of the world’s largest cement producers and among the fastest-growing construction markets, India’s material choices will influence the carbon trajectory of its built environment for decades. As Krishan observed, sustainability solutions in economies such as India must not remain limited to laboratory success. They must be scalable, commercially viable and practical at national level.

The innovation gap: From technology to market

Experts believe that there is a need to bridge the innovation gaps for making decarbonisation in cement and concrete scalable. Devika Wattal of GCCA, explained, “The starting point must be the core cement manufacturing process itself. The first and foremost is the heart of our process, the heart of cement manufacturing. How do we reduce clinker? That is always a topic where industry is working very intrinsically.”

Clinker reduction remains one of the most important pathways for lowering emissions in cement. Since clinker production is energy-intensive and chemically emits carbon dioxide, reducing the clinker factor through supplementary cementitious materials (SCMs), blended cements and new chemistries can have a significant impact. Wattal also noted that carbon capture, utilisation and storage (CCUS) will have a role, though it may not be the first lever for all markets.

However, she stressed that innovation cannot stop at technology development. A solution that works in the lab must also be adaptable to industry, scalable in production and acceptable in construction practice. “It is important for that innovation to be adaptable, to be scalable, and so that it can be executed in real time,” she said.

Wattal also called for stronger enabling systems around innovation. These include performance-based standards, product-level embodied carbon databases and clearer frameworks for evaluating green materials. Without these, low-carbon cement products may struggle to compete with conventional materials in procurement and design.

R&D must balance carbon, cost and performance

Bringing in the R&D perspective into the discussion, Dr Hemantkumar Aiyer of Nuvoco Vistas emphasised that low-carbon cement development cannot be treated as a single-variable exercise. Cement must perform in real construction conditions. It must deliver strength, durability, consistency and cost competitiveness, while also reducing carbon.

“The root of understanding and balancing all these aspects lies in materials, and knowing the materials,” he said.

According to Dr Aiyer, R&D teams must understand the variability of raw materials such as fly ash, slag and clinker. Different sources produce different material behaviours. This makes mix optimisation, material characterisation and processing-property relationships critical. When performance is affected, cement manufacturers must understand how strength enhancers, admixtures and other performance chemicals interact with the material system.

He also linked material science with process efficiency. Clinkerisation takes place at extremely high temperatures, around 1,400 to 1,450 degrees Celsius. Any improvement in raw mix design, process control or energy optimisation can, therefore, help reduce emissions and cost. Dr Aiyer pointed to artificial intelligence-based optimisation, Cement 4.0 tools and advanced software as important enablers for real-time process and material control.

“The more you understand the materials, the more you can control it,” he said.

LC3: The promise is proven, the sequencing is not

Limestone calcined clay cement, commonly referred to as LC3, has attracted global attention because it can reduce clinker content significantly by using calcined clay and limestone while maintaining performance in many applications. Kiranmai Sanagavarapu of Fuller Technologies said the technology itself has already moved beyond proof of concept. Fuller Technologies has worked with calcined clay technology for nearly two decades and has seen plants running in France and Ghana. These plants, she said, are meeting local and national specifications, while the economics are beginning to make sense.

“The calciner is performing, the economics is stacking up, it is making business sense to produce,” she said.

But if the technology is viable, why has adoption not scaled faster? For Sanagavarapu, the answer lies in project sequencing. Too often, clay characterisation happens after equipment is specified. This, she warned, is a backward approach because calciner design depends on clay mineralogy, kaolinite content, iron levels, reactivity, moisture and other variables.

“If you don’t know what your deposit looks like before you commit for the equipment, you are, in a way, going blind into designing,” she said.

She also identified permitting and plant integration as major bottlenecks. Environmental clearances, mining permissions and local regulatory approvals must begin early. Similarly, calcined clay must be integrated into existing grinding, blending and logistics systems from the design stage, not treated as an afterthought during commissioning.

India already has IS 18189:2023 standard for LC3, but Sanagavarapu pointed out that the standard is not yet visible enough in procurement documents. “The gap between what is technically being permitted and what the procurement is asking is the single biggest bottleneck,” she said.

In her view, successful scale-up depends on getting the sequence right: clay characterisation first, permitting in parallel, standards aligned with construction, and integration built into plant design.

India’s LC3 journey: Progress, but demand remains thin

Providing details of India’s LC3 commercialisation experience, Vaibhav Rathi of GIZ noted that JK Cement carried out the first commercial production of LC3 at its Rajasthan plant, followed by JK Lakshmi Cement three months later. These initiatives were supported by the International Climate Initiative of the Government of Germany, with IIT Delhi contributing deep institutional knowledge on LC3 research and BIS certification.

Rathi said India’s early experience has produced clear lessons. One of the biggest was the need to build capacity among regulators. While BIS certification existed, State Pollution Control Boards were unfamiliar with the technology and unsure about the approval pathway.

“The capacity building is not just needed amongst the producer and the users of the cement, but also the regulators who are working with this technology for the first time,” he said.

He also highlighted the need for better information on China clay deposits. Since China clay is currently classified as a minor mineral, centralised data on availability, quality and location is limited. If cement manufacturers are to adopt LC3 at scale, stronger mineral intelligence will be important.

The third issue is demand. LC3 has already been used in projects such as Palava City in Mumbai and Noida International Airport, but these remain limited examples. “It is in a chicken and egg situation,” Rathi said. “Cement companies are saying we need more demand, and users are saying there is not enough cement available.”

Public procurement, he suggested, could help break this cycle. If agencies such as CPWD and other public bodies begin testing, accepting and specifying LC3, it could create the market confidence needed for cement companies to invest in production and storage.

Building codes must catch up with innovation

Dr Sunita Purushottam of GBPN India argued that material choices will determine built environment emissions over the long term, but India’s current policy signals remain fragmented. Although LC3 has received BIS recognition, she pointed out that building codes, municipal bylaws, schedules of rates and sustainability codes do not yet provide uniform guidance on low-carbon cement.

“The current cement regulations are largely prescriptive and favouring traditional materials,” she said. This limits the ability of alternative materials to compete on performance, durability and emissions.

Dr Purushottam also raised the issue of taxation. Cement, including LC3, currently falls under the same GST bracket as conventional cement. A differentiated tax structure, she argued, could help accelerate market adoption. “In order for the market to demand LC3, that differentiation in the GST could go a long way,” she said.

She noted that green building certifications such as IGBC and GRIHA are already creating demand for low-carbon materials by assigning points for embodied carbon and sustainable material use. However, she said large-scale adoption will require regulatory mandates, particularly through building codes and state-level notifications.

She also cautioned that low-carbon cement alone does not solve the entire building performance problem. A material may reduce embodied carbon, but the operational carbon of a building depends on thermal performance, design, insulation and energy use. “The energy part has two elements,” she said. “One is the embodied carbon of the material itself, and the other is the operational carbon.”

Collaboration is the bridge between invention and impact

Wattal said GCCA sees innovation as a strategic priority and works through platforms that connect industry with academia and start-ups. “There is no way we will decarbonise our sector without innovation,” she said.

However, she stressed that research must be connected to actual industry challenges. Innovations developed in isolation may fail when they encounter real-world barriers such as raw material variability, plant integration, cost, standards and finance. Start-ups, too, need industry mentorship and scale-up pathways.

Wattal also flagged the importance of finance. Even strong technologies may struggle to attract investment if there is no common understanding of bankability. “We have always put projects into, is this a bankable project? But the definition of a bankable project has never been defined,” she said.

For India, she saw strong potential in its academic and start-up ecosystem, but said the challenge lies in alignment and prioritisation. The country has the research base, industrial capacity and market size. What it now needs is a coordinated route from innovation to deployment.

There is a practical concern for cement manufacturers: how can existing plants be adapted for lower emissions without compromising reliability or commercial viability?

Kiranmai Sanagavarapu addressed, “The reliability risk in calcined clay retrofit is definitely real, but it is almost always self-inflicted. The risk arises when a new process is added to an existing circuit without properly redesigning grinding and blending configurations.”

Existing cement plants, she explained, can take two broad routes. The first is external sourcing of calcined clay combined with mill optimisation. This requires lower capital investment and can potentially move in 12 to 18 months if other conditions are in place. It may reduce emissions by around 20 to 30 per cent. The second route is integrated calcination on site, which requires higher capital expenditure and longer lead times, but provides greater control over quality, supply and emissions reduction potential.

For Sanagavarapu, the principle is simple: low-carbon retrofits must be designed with intent. “Design it with an intent properly from the start. Start in the market conditions where the economics are already working,” she said.

Circularity: The overlooked advantage

According to Vaibhav Rathi, fly ash and slag are already well established in cement and construction (C&D), but construction and demolition waste remains underutilised. “C&D waste is a growing business opportunity which not many have taken up,” he said. India’s continuous construction and demolition activity creates huge volumes of waste, much of which contributes to air pollution, land degradation and material inefficiency. With the right processing and standards, this waste can be converted into useful construction products.

Rathi also pointed out that LC3 has a circular economy dimension that is often overlooked. It can use low-grade kaolin-rich clay left behind after high-grade clay is extracted for other applications. “LC3 is not only a low-carbon solution, but also a circular economy solution,” he said.

At the same time, he cautioned that LC3 in India is not yet cheap because it has not reached scale. Site-specific techno-commercial feasibility studies, supported jointly by development agencies and industry, could help companies assess whether LC3 production makes technical and financial sense at a given location.

Dr Purushottam added that India must address both low-carbon cement and construction waste together. “Both low-carbon cement and C&D waste go hand in hand. India does not have an option but to work on both,” she said.

Dr Aiyer called for policy shifts from both government and industry, including preferential purchasing of sustainable materials, minimum supplementary cementitious material requirements in public and public-private projects, and faster regulatory implementation. “If we can fast-track the regulatory standards and their implementation on the ground, that is the way to go,” he said.

From green ambition to green construction

Cement innovation is no longer only about chemistry. It is about systems. Low-carbon cement will scale only when technology, standards, procurement, finance, regulation, education and construction practice move together.

LC3 and other low-carbon technologies have shown promise. India has early commercial examples, strong research capability and growing market interest. But mainstream adoption will depend on whether demand can be created, regulators can be capacitated, standards can be embedded in procurement, and manufacturers can see a clear business case.

For a country building at India’s scale, the opportunity is enormous. Cement will continue to be central to infrastructure and urban development. The challenge now is to ensure that the cement used in India’s growth story carries a lower carbon burden.

  • Rakesh Rao

Participate in Cement Expo 2026 and discover how next-gen infrastructure can be built with innovations in cement.

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Indian Railways Plans Green Fly Ash Transport Network

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Specialised rail logistics will move fly ash from power plants to infrastructure industries.

New Delhi

Indian Railways is planning a large-scale green logistics initiative to transport fly ash from thermal power plants to industries where it can be reused in infrastructure and construction activities.

The initiative was discussed during a review meeting chaired by Union Minister for Railways Ashwini Vaishnaw. Union Ministers of State for Railways V Somanna and Ravneet Singh Bittu were also present.

India generates nearly 340 million tonnes of fly ash every year from thermal power plants. The proposed initiative aims to create an efficient rail-based transport system using specialised containers and dedicated logistics arrangements to move fly ash safely from power plants to end-use industries.

Fly ash is widely used in road construction, cement manufacturing, brick production, concrete, blocks and boards. By improving its movement through the railway network, the initiative is expected to support better utilisation of this industrial by-product while reducing environmental concerns linked to storage and disposal.

The move also aligns with India’s circular economy goals by converting waste from thermal power generation into a useful raw material for the construction and infrastructure sectors. Wider availability of fly ash can help reduce material costs in areas such as bricks and cement, supporting more affordable infrastructure and housing development.

Through this initiative, Indian Railways aims to provide a cleaner, safer and more organised transport solution for fly ash, turning an environmental challenge into an infrastructure resource.

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