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Today’s blended cements have its origin in the old Roman construction. Due to technological advancements [now] the similar cements are available in the new forms.

The Romans started making concrete more than 2,000 years ago, but it wasn’t quite like today’s concrete. They had a different formula, which resulted in a substance that was not as strong as the modern product. ‘Roman concrete is . . . considerably weaker than modern concretes. It’s approximately ten times weaker,’ says Renato Perucchio, a mechanical engineer at the University of Rochester in New York. ‘What this material is assumed to have is phenomenal resistance over time.’ That resistance, or durability against the elements, may be due to one of the concrete’s key ingredients: volcanic ash. Modern concrete is a mix of a lime-based cement, water, sand and so-called aggregates such as fine gravel.

Indian scenario
Surkhi, was the commonest pozzolanic materials used in India resembles volcanic ash. It has been used along with lime in many of our old structures, before modern Portland cement has taken its roots in India. Even after Portland cement made its appearance in the field of construction, Surkhi was used as an admixture to remedy some of the shortcomings of cement concrete. Surkhi was one of the main constituents in waterproofing treatments in conjunction with lime and sometimes even with cement for extending valuable pozzolanic action to make the treatment impervious. Surkhi is an artificial pozzolana made by powdering bricks or burnt clay balls. In some major works, for large scale production of Surkhi, clay balls are specially burnt for this purpose and then powdered. By its nature, it is a very complex material differing widely in its qualities and performances. Bhakra Nangal Dam is a standing ovation to the use of Surkhi in the construction.

Policy hurdles
The Indian cement sector had been under strict government control for almost the whole of the period 1969 to 1982. Government intervention took place both directly and indirectly. Direct intervention happened in the form of government control over production, capacity and distribution of cement, while indirect intervention took the form of price control. During this period, many companies and their plants started off but still growth was not seen at the desired rate. In 1977, higher prices were allowed for cement produced by new plants or major expansions of existing plants. Due to slow development, the uniform price imposed by the government, was substituted by a three-tier price system in 1979. Different prices were assigned to cement produced in low, medium and high cost plants.

Later on during the shortage of cement the producers were allowed to use Surkhi, burnt clay as a pozzolanic material to produce more quantity of cement and then the problem of quality started. Indiscriminate use of any sort of burnt clay material, without ensuring proper quality control norms created many issues with Pozzolana cement and gave it a bad name in late seventies and early eighties. Therefore initially when blended cements were reintroduced based on fly ash as a performance enhancer had to face users resistance. Now the blended cement available based with fly ash as a pozzolana is much different than the Surkhi-based Pozzolana cement.

Present scene
As per the papers published by NCCBM, the production of ordinary Portland Cement in India has currently remained to about 25 per cent and that of Portland Pozzolana cement has steadily increased to about 67 per cent. The production of Portland slag cement is limited to 8 per cent. The production trend of different types of cement such as OPC, PPC, PSC and others in the last decade indicates that the trend is more towards blended cements. This is a favourable change in the product mix of Indian cement industry as PPC and PSC are more specialised types of cement with advantages in terms of better durability characteristics.

Many developed countries started using such blended cements in large quantities in construction of critical structures such as rocket launch pads, sea water jetties, huge dams, etc. Production of blended cements directly increases the plant capacity without any need for creating additional clinker making capacity. In an environment of growing competition, another development has been the introduction of higher grades of cement particularly for OPC. However, realisation is growing fast amongst the consumers at large, that the properties of durability are of greater importance than strength.

Improvement in construction technologies and the need for durable construction in different aggressive environments have enhanced the use of blended cements. Under such prevailing trend the need of stringent control on quality parameters related to raw materials and cement becomes essential. In the present paper, efforts have been made to present quality trends of OPC and PPC as their production is around 92 per cent of total. In order to conserve high grade limestone and fuels, thrust is given for the production of variety of cements using inferior grade and/or alternative raw materials by adopting state-of-art manufacturing technology. To maintain the quality of cements and to promote the use of different types of wastes/by-products or inferior grade raw materials in the cement manufacture, BIS (Bureau of Indian Standards) has incorporated amendments in the standard specifications and also revised some of the specifications. The salient features of the modifications in standards are:

  • Increase in limit of pozzolana in PPC
  • Increase in limit of granulated blast furnace slag in PSC
  • Increase in limit of MgO in PSC
  • Specifying the upper limit of compressive strength at 672 ? 4 hrs for OPC-33 & 43 grades
  • Addition of performance improver up to 5 per cent in OPC
  • Enhancing the limits of insoluble residue
  • Increasing the limits of SO3 to 3.5 per cent Specifying requirements of cement for pre-cast concrete

Most of the cement plants in India have the state-of-the-art technology and are able to achieve their capacity utilisation as per the market demand. Cement industry is going ahead with a modification and upgradation of technology particularly in energy conservation. Cement industry’s average energy consumption is about 725 kcal/kg clinker thermal energy and 80 kWh/t cement electrical energy.

Efforts are on relating to utilisation of alternate energy sources/fuels either partially or fully substitute coal in cement manufacture in the coming years, namely, pet coke, lignite, natural gas, and biomass wastes including fruit of Jatropha Carcus, Pongamia and Algae. Although the modern cement plants have incorporated the latest technology, yet there is scope for further improvement in the areas of coprocessing of waste derived/hazardous combustible wastes as fuel, cogeneration of power, bulk transport of cement, palletising and shrink wrapping for packing and dispatch.

Future trends
The R&D activities and thrust to reduce CO2 emission associated with properties has resulted a trend towards the increased use of blended cement with the share of blended cements increasing to 75 per cent followed by Ordinary Portland Cement (OPC) (? 25 per cent). Fly ash based Portland Pozzolana Cement (PPC) contributes the major share (67 per cent) of the total production with 8 per cent of Portland Slag Cement (PSC). In addition to conservation of natural resources, fuel and reduction of green house gases, there are other advantages of using blended cements.

The cement industry in India has also shown potential to utilise hazardous waste. The awareness on utilisation of wastes and environmental pollutants in the manufacture of cement have increased many folds in the last decade. The production of PPC and PSC of uniform quality by utilising more proportion of fly ash and/or slag could be possible by their assured consumer acceptance and research activities.

By and large (BIS) Indian specifications have kept pace with the specifications from developed countries and have been quite dynamic with times and technology. The amendments in the specification are expected to come in the shortest possible of times, which is rather difficult for such a large country. Recently BIS has come out with codes for composite cement which allows the use of two different SCMs like fly ash and slag together. It is one step forward. There is a need for standard specifications for composite cements, using variety of wastes and keeping in view the pragmatic approach of utilisation of cement in different types of construction activities has also been realised.

Various wastes like lead-zinc slag, copper slag, steel slag, marble dust, which were not allowed for utilisation earlier, have now been identified as suitable material for the use in cement and other building products. As availability of coal and limestone are limited and soon these will be finished and on the other hand the requirement for cement is ever increasing. Hence adopting modern technologies and alternate materials is very essential for cement industry to meet this gap.

Cenospheres are one of the most desired by products of fly ash. They are small hollow spheres with roughly 10-1,000 ?m in diameter and constitute about 1-2 per cent of the fly ash obtained from the coal combustion processes. Because of their specific properties, namely their low density and high mechanical strength, cenospheres are an important subject of coal fired power plants. Research results indicate that cenospheres from coal combustion are constituted by aluminosilicate glasses with some crystalline phases like quartz, mullite and calcite. The high alumina content – roughly 25-27 wt per cent is responsible for the high mechanical strength, while density of most cenospheres is lower than 1 g/cm3. Regarding the formation process, there are correlations between the amount of cenospheres and the sodium and calcium content, in the different fly ash samples.

The economics of blended cements will largely depend on the landed cost of fly ash or slag. The common belief that it is a waste material and can be given away at throw away price has already vanished. Cement companies are prepared to pay better rates for consistent quality of fly ash.

Reference: Quality Trend In Indian Cements – A Decade Appraisal

AUTHORS: US Sinha, K Bhatnagar, R Gupta and MM Ali of National Council for Cement and Building Materials, India (NCCBM)

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Concrete

PROMECON introduces infrared-based tertiary air measurement system for cement kilns

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The new solution promisescontinuous, real-time tertiary air flow measurement in cement plant operations.

PROMECON GmbH has launched the McON IR Compact, an infrared-based measuring system designed to deliver continuous, real-time tertiary air flow measurement in cement plant operations. The system addresses the longstanding process control challenge of accurate tertiary air monitoring under extreme kiln conditions. It uses patented infrared time-of-flight measurement technology that operates without calibration or maintenance intervention.

Precise tertiary air measurement is a critical requirement for stable rotary kiln operation. The McON IR Compact is engineered to function reliably at temperatures up to 1,200°C and in the presence of abrasive clinker dust. Its vector-based digital measurement architecture ensures that readings remain unaffected by swirl, dust deposits or drift. Due to these conditions conventional measurement systems in pyroprocess environments are often compromised.

The system is fully non-intrusive and requires no K-factors, recalibration or periodic readjustment, enabling years of uninterrupted operation. This design directly supports plant availability and reduces the maintenance overhead typically associated with process instrumentation in high-temperature zones.

PROMECON has deployed the McON IR Compact at multiple cement facilities, including Warta Cement in Poland. Plant operators report that the system has aided in identifying blockages, optimising purging cycles for gas burners, and supplying accurate flow data for AI-based process optimisation programmes. The practical outcomes include more stable kiln operation, improved process control, and earlier detection of process disturbances.

On the energy side, real-time tertiary air data enables reduction in induced draft fan load and helps flatten process oscillations across the pyroprocess. This translates to lower fuel and energy consumption, fewer unplanned shutdowns, and a measurable reduction in NOx peaks. This directly reflects on the downstream cost implications for plants operating SCR or SNCR systems for emissions compliance.

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Concrete

Filtration Technology is Critical for Efficient Logistics

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Niranjan Kirloskar, MD, Fleetguard Filters, makes the case that filtration technology, which has been long treated as a routine consumable, is in fact a strategic performance enabler across every stage of cement production and logistics.

India’s cement industry forms the core for infrastructure growth of the country. With an expected compound annual growth rate of six to eight per cent, India has secured its position as the second-largest cement producer globally. This growth is a result of the increasing demand across, resulting in capacity expansion. Consequently, cement manufacturers are now also focusing on running the factories as efficiently as possible to stay competitive and profitable.
While a large portion of focus still remains on production technologies and capacity utilisation, the hidden factor in profitability is the efficiency of cement logistics. The logistics alone account for nearly 30 per cent to 40 per cent of the total cost of cement, making efficiency in this segment a key lever for profitability and reliability.
In the midst of this complex and high-intensity ecosystem, filtration often remains one of the most underappreciated yet essential enablers of performance.

A demanding operational landscape
Cement production and logistics inherently operate in some of the harshest industrial environments. With processes such as quarrying, crushing, grinding, clinker production, and bulk material handling expose the machinery to constant high temperatures, heavy loads, and dust, often the silent destructive force for engines.
The ecosystem is abrasive, and often one with a high contamination index. These challenging conditions demand equipment such as the excavators, crushers, compressors, and transport vehicles to perform and perform efficiently. The continuous exposure to contamination across every aspect like air, fuel, lubrication, and even hydraulic systems causes long-term damage. Studies have also shown that 70 to 80 per cent of hydraulic system failures are directly linked to contamination, while primary cause of engine wear is inadequate air filtration.
For engines as heavy as these, even a minor contaminant has a cascading effect; reducing efficiency, performance and culminating to unplanned downtime. Particles as small as 5 to 10 microns, far smaller than a human hair (~70 microns), can cause significant damage to critical engine components. In an industry where margins are closely linked to operational efficiency, such disruptions can significantly affect both cost structures and delivery timelines.

Dust management: A persistent challenge
Dust is a natural by-product in cement operations. From drilling and blasting in the quarries to packing in plants, this fine particulate matter does occupy a large space in operations. Dust concentration levels in quarry and crushing zones often create extremely high particulate exposure for equipment. These fine particles, when enter the engines and critical systems, accelerates the wear and tear of the component, affecting directly the operational efficiency. Over time every block fall; engine performance declines, fuel consumption rises, and maintenance cycles shorten. In this case, effective air filtration is the natural first line of defence. Advanced filtration systems are designed to capture high volumes of particulate matter while maintaining consistent airflow, ensuring that engines and equipment operate under optimal conditions.
In high-dust applications, as in cement production, even the filtration systems are expected to sustain performance over extended periods without the need of frequent replacement. This becomes crucial in remote quarry locations where access to frequent maintenance may be limited.

Fluid cleanliness and system integrity
Beyond air filtration, fluid systems also play a crucial role for equipment reliability in cement operations. Fuel systems are required to remain free from contaminants for efficient working of combustion and injection protection. Additionally, lubrication systems also need to maintain the oil purity to reduce friction and prevent any premature wear of moving parts. The hydraulic systems, which are key to several heavy equipment operations, are especially sensitive to contamination.
If fine particles or water enters these systems, it can lead to reduced efficiency, erratic performance, and eventual failure of the system. Modern filtration systems are designed with high-efficiency media capable of removing extremely fine contaminants, with advanced fuel and oil filtration solutions filtering particles as small as two to five microns. Multi-stage filtration systems further ensure that fluid performance is maintained even under challenging operating conditions.
Another critical aspect of fuel systems is water separation. Removing moisture helps prevent corrosion, improves combustion efficiency and enhances overall engine reliability. Modern water separation technologies can achieve over 95 per cent efficiency in removing water from fuel systems.

Ensuring reliability across the value chain
Filtration plays a critical role across every stage of cement logistics:
• Quarry operations: Equipment operates in highly abrasive environments, requiring strong protection against dust ingress and hydraulic contamination.
• Processing units: Crushers, kilns, and grinding mills depend on clean lubrication and cooling systems to sustain continuous operations.
• Material handling systems: Pneumatic and mechanical systems rely on clean air and fluid systems for efficiency and reliability.
• Transportation networks: Bulk carriers and trucks must maintain engine health and fuel efficiency to ensure timely deliveries.
Across these operations, filtration plays a vital role; as it supports consistent equipment performance while reducing the risk of unexpected failures.
Effective filtration solutions can reduce unscheduled equipment failures by 30 to 50 per cent across heavy-duty operations.

Uptime as a strategic imperative
In cement manufacturing, uptime is currency. Downtime not only delays the production, but it also greatly impacts the supply commitments and logistics planning. With the right filtration systems, contaminants are kept at bay from entering the
critical systems, and they also significantly extend the service intervals.
Optimised filtration can extend service intervals by 20 to 40 per cent, reducing maintenance frequency while maintaining consistent performance across demanding operating conditions. Filtration systems designed for heavy-duty applications sustain efficiency throughout their lifecycle, ensuring reliable protection with minimal interruptions. This leads to improved equipment availability, lower maintenance costs, and more predictable operations, with well-maintained systems capable of achieving uptime levels of over 90 to 95 per cent in challenging cement environments.

Supporting emission and sustainability goals
With the rising environmental awareness, the cement industry too is aligning with the stricter norms and sustainability targets. In this scenario, the operational efficiency is directly linked to emission control.

Air and fuel systems that are clean enable
much more efficient combustion. They also reduce emissions from both the stationary equipment and transport fleets. Similarly, with a well-maintained fluid cleanliness, emission systems function better. Poor combustion due to contamination can increase emissions by 5 to 10 per cent, making clean systems critical for compliance.
Additionally, efficient and longer lasting filtration systems significantly reduce any waste generation and contribute to increased sustainable maintenance practices. Extended-life filtration solutions can reduce filter disposal and maintenance waste by 15 to 20 per cent. Smart and efficient filtration in this case plays an important role in meeting the both regulatory and environmental objectives within the industry.

Advancements in filtration technology
Over the years, there has been a significant evolution in the filtration technology to meet the modern industrial applications.
Key developments include:
• High-efficiency filtration media capable of capturing very fine particles without restricting flow
• Compact and integrated designs that combine multiple filtration functions
• Extended service life solutions that reduce replacement frequency and maintenance downtime
• Application-specific engineering tailored to different stages of cement operations
Modern multi-layer filtration media can improve dust-holding capacity by up to two to three times compared to conventional systems, while maintaining consistent performance. These advancements have transformed filtration from a basic maintenance component into a critical performance system.

Adapting to diverse operating conditions
The cement industry of India operates across diverse geographies. Spanning across regions with arid regions with higher dust levels, to the coastal areas with higher humidity, challenges of each region pose different threats to the engines. Modern filtration systems are thus tailored to address these unique challenges of each region.
Indian operating environments often range from 0°C to over 50°C, with some of the highest dust loads globally in mining zones.
Additionally, filtration technology can also be customised to variations which then align the system design with factors like dust load, temperature, and equipment usage patterns. Equipment utilisation levels in India are typically higher than global averages, making robust filtration even more critical. This approach ensures optimal performance and durability across different operational contexts.

Impact on total cost of ownership
Filtration has a direct and measurable impact on the total cost of ownership of equipment.
Effective filtration leads to:
• Lower wear and tear on critical components
• Reduced maintenance and repair costs
• Improved fuel efficiency
• Extended equipment life
• Higher operational uptime
Effective filtration can extend engine life by 20 to 30 per cent and reduce overall maintenance costs by 15 to 25 per cent over the equipment lifecycle. These benefits collectively enhance productivity and reduce lifecycle costs. Conversely, inadequate filtration can result in frequent breakdowns, increased maintenance expenditure, and reduced asset utilisation.

Building a more efficient cement ecosystem
With the rising demand across various sectors, the cement industry is expected to expand at an unprecedented rate. This growth is forcing the production to move towards a more efficient and resilient system of operations. This requires attention not only to production technologies but also to the supporting systems that enable consistent performance. Filtration must be viewed as a strategic investment rather than a routine consumable. By ensuring the cleanliness of air and fluids across systems, it supports reliability, efficiency, and sustainability.

The road ahead
The future of cement logistics will be shaped by increasing mechanisation, digital monitoring, and stricter environmental standards. The industry is also witnessing a shift towards predictive maintenance and condition monitoring, where filtration performance is increasingly integrated with real-time equipment diagnostics.
In this evolving landscape, the role of filtration will become even more critical. As equipment becomes more advanced and operating conditions more demanding, the need for precise contamination control will continue to grow. From quarry to construction site, filtration technology underpins the performance of every critical system. It enables equipment to operate efficiently, reduces operational risks, and supports the industry’s broader goals of growth and sustainability. In many ways, it is the unseen force that keeps the cement ecosystem moving, quietly ensuring that every link in the value chain performs as expected.

About the author
Niranjan Kirloskar, Managing Director, Fleetguard Filters, is focused on driving innovation, operational excellence, and long-term business growth through strategic and people-centric leadership. With a strong foundation in ethics and forward-thinking decision-making, he champions a culture of collaboration, accountability, and technological advancement.

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Concrete

Cement’s Next Fuel Shift

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Jignesh Kindaria highlights how Thermal Substitution Rate (TSR) is emerging as a critical lever for cost savings, decarbonisation and competitive advantage in the cement industry.

India is simultaneously grappling with two crises: a mounting waste emergency and an urgent need to decarbonise its most carbon-intensive industries. The cement sector, the second-largest in the world and the backbone of the nation’s infrastructure ambitions, sits at the centre of both. It consumes enormous quantities of fossil fuel, and it has the technical capacity to consume something else entirely: the waste our cities cannot get rid of.
According to CPCB and NITI Aayog projections, India generates approximately 62.4 million tonnes of municipal solid waste annually, with that figure expected to reach 165 million tonnes by 2030. Much of this waste is energy-rich and non-recyclable. At the same time, cement kilns operate at material temperatures of approximately 1,450 degrees Celsius, with gas temperatures reaching 2,000 degrees. This high-temperature environment is ideal for co-processing, ensuring the complete thermal destruction of organic compounds without generating toxic residues. The physics are in our favour. The infrastructure is not.
Pre-processing is not the support act for co-processing. It is the main event. Get the particle size wrong, get the moisture wrong, get the calorific value wrong and your kiln thermal stability will suffer the consequences.

The regulatory push is real
The Solid Waste Management (SWM) Rules 2026 mandate that cement plants progressively replace solid fossil fuels with Refuse-Derived Fuel (RDF), starting at a 5 per cent baseline and scaling to 15 per cent within six years. NITI Aayog’s 2026 Roadmap for Cement Sector Decarbonisation targets 20 to 25 per cent Thermal Substitution Rate (TSR) by 2030. Beyond compliance, every tonne of coal replaced by RDF generates measurable carbon reductions which is monetisable under India’s emerging Carbon Credit Trading Scheme (CCTS). TSR is no longer a sustainability metric. It is a financial lever.
Yet our own field assessments across multiple Indian cement plants reveal a sobering reality: the primary barrier to scaling AFR adoption is not waste availability. It is the fragmented and under-engineered pre-processing ecosystem that sits between the waste and the kiln.

Why Indian waste is a different engineering problem
Indian municipal solid waste is not the material that imported shredding equipment was designed for. Our waste streams frequently exceed 40 per cent to 50 per cent moisture content, particularly during monsoon cycles, saturated with abrasive inerts including sand, glass, and stone. Plants relying on imported OEM equipment face months of downtime awaiting proprietary spare parts. Machines built for segregated, low-moisture waste fail quickly and disrupt the entire pre-processing operation in Indian conditions.
The two most common failures we observe are what I call the biting teeth problem and the chewing teeth problem. Plants relying solely on a primary shredder reduce bulk waste to large fractions, but the output remains too coarse for stable kiln combustion. Others attempt to use a secondary shredder as a standalone unit without a primary stage to pre-size the feed, leading to catastrophic mechanical failure. When both stages are present but mismatched in throughput capacity, the system becomes a bottleneck. Achieving the 40 to 70 tonnes per hour required for meaningful coal displacement demands a precisely coordinated two-stage process.

Engineering a made-in-India answer
At Fornnax, our response to these challenges is grounded in one principle: Indian waste demands Indian engineering. Our systems are built around feedstock homogeneity, the holy grail of kiln stability. Consistent particle size and predictable calorific value are the foundation of stable kiln combustion. Without them, no TSR target is achievable at scale.
Our SR-MAX2500 Dual Shaft Primary Shredder (Hydraulic Drive) processes raw, baled, or loosely mixed MSW, C&I waste, bulky waste, and plastics, reducing them to approximately 150 mm fractions at throughputs of up to 40 tonnes per hour. The R-MAX 3300 Single Shaft Secondary Shredder (Hydraulic Drive), introduced in 2025, takes that primary output and produces RDF fractions in the 30 to 80 mm range at up to 30 tonnes per hour, specifically optimised for consistent kiln feeding. We have also introduced electric drive configurations under the SR-100 HD series, with capacities between 5 and 40 tonnes per hour, already operational at a leading Indian waste-processing facility.
Looking ahead, Fornnax is expanding its portfolio with the upcoming SR-MAX3600 Hydraulic Drive primary shredder at up to 70 tonnes per hour and the R-MAX2100 Hydraulic drive secondary shredder at up to 20 tonnes per hour, designed specifically for the large-scale throughput that higher TSR ambitions require.

The investment case is now
The 2070 Net-Zero target is not a distant goal for India’s cement sector. It starts today, with decisions being made on the plant floor.
The SWM Rules 2026 are already in effect, requiring cement plants to replace coal with RDF. Carbon credit markets are opening up, and coal prices are not going to get cheaper. Every tonne of coal a cement plant replaces with waste-derived fuel saves money on one side and generates carbon credit revenue on the other. Pre-processing infrastructure is no longer just a compliance requirement. It is a business investment with a measurable return.
The good news is that nothing is missing. The technology works. The waste is available in every Indian city. The government has provided the policy direction. The only thing standing between where the industry is today and where it needs to be is the commitment to build the right infrastructure.
The cement companies that move now will not just meet the regulations. They will be ahead of every competitor that waits.

About the author
Jignesh Kundaria is the Director and CEO of Fornnax Technology. Over an experience spanning more than two decades in the recycling industry, he has established himself as one of India’s foremost voices on waste-to-fuel technology and alternative fuel infrastructure.

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