Economy & Market

Safety is at the centre of everything that we do

Published

4 years ago

February 1, 2022

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Perumal Jagatheesan, Safety Head, HeidelbergCement India and Zuari Cement, discusses the safety norms and standards at a cement plant, while underscoring the importance of training, safety protocols and practices and the use of technology at a cement plant.

How would you define a safe cement plant? What are the major areas of concern for safety in the cement work environment?
Safety in cement plant starts from its design itself, carrying out proper layout and machinery safety protection. It is designed to limit the risk to personnel for accident or injury. Different hazards involved in the process starts from extracting limestone from mines to dispatching the cement. Robust safety management system implementation is vital for safe cement plant to mitigate the hazards involved in blasting activity in mines, heavy mobile equipment, heavy crushing machineries, material transporting systems and clicker production.
Various hazards includes: blasting and mining of limestone, high temperatures in pre-heater tower (as high as 900 degrees centigrade), storage of coal in sheds, cement grinding, heavy inbound and outbound truck movements carrying all raw materials and the product from the plant etc.
Safety management system includes risk assessment and control measures for all the processing activities, well designed permit system, safeguarded machineries, firefighting systems, clean workplace, safety audit, trained and competent manpower are important elements to have safe cement plant. Major areas of concerns are the maintenance work in confined space, pre-heater cyclones and silos, work at height jobs, materials transportation systems, heavy mobile equipment and truck movement are major risks in a cement plant operation.

What are the key challenges in ensuring safety at a cement plant?
People in any industry do not appreciate to work in a hazardous work environment. Hence, our slogan “Someone in waiting for you at home” explains well about itself.
The manufacturing and distribution of cement is a high-risk enterprise but creating safe work environment in the cement industry is achievable. There are many causes of accidents in cement industry, however there are three major areas that can lead to serious incidents.

Traffic and mobile equipment: Traffic is caused from inbound and outbound trucks. Mobile equipment are dumpers that bring limestone from mines to crushers. Rigorous intra and inter plant movement of traffic is an area of major risk.
Fall from height and falling objects
Moving/Starting Equipment

Some of other more serious hazards include working in confined spaces and working with hot materials in the pre-heater.
There are several key-factors to achieving sustainable safety in the cement industry we have implemented the following health and safety initiatives at all our HeidelbergCement India plants to keep the safety momentum and safety awareness throughout out the year. We have monthly safety gate meeting, monthly safety theme and communication, plant safety star award program which is once in four months, strict compliance of our safety cardinal rules, safety zone system, hazard identification and risk assessment control measures, work permits and procedures, safety inspections and audits, fire prevention and protection, accident and near miss incident reporting, and investigation to identify the root cause along with implementation of corrective actions with training on lessons learned across the HeidelbergCement India plants.
For example, of a near miss incident or any incident happened at any plant, incident learnings will be communicated across all HC India Plants to take appropriate corrective actions if similar unsafe situation exists in their plant.
Mock drill and emergency handling, safety induction and behavior safety training for workers at all our plants, award and penalty system, review of safety system for continual improvement, safety conversation with workmen by line managers, and monitoring implementation by inspecting and auditing controls to ensure they are working as expected by the company. Ensuring operating process and training materials are updated regularly and incase of any new process/system added in the plant. These are the various safety management systems to ensure safety in operation and maintenance of the plants.

What is your first response in case of hazard in the plant?
Our first response would be to immediately isolate the hazard, to prevent personal interference or people going in the proximity of the hazard.
Hazards can be classified into three categories that is low, medium and major.
When a major hazard occurs, we immediately stop the work and take the corrective action immediately. During such circumstances, the area is isolated, and the operational team is called to discuss and make corrective and preventive actions in the stipulated target time.

Tell us more about the personal safety equipment used in the plant by working professionals.
In safety management system, personal protective equipment (PPE) is the last line of defense to prevent injuries, but it is very essential and mandatory. In the hierarchy of most effective controls to least effective controls are, the first one is elimination, which means physically remove the hazard. Second one is substitution, which means replace the hazard. Third one is engineering controls, which means isolate people from hazard by providing guarding. Fourth one is administrative controls, that includes change the way people work. Last control is the personal protective equipment (PPE) which protect the worker. PPE will not prevent the accidents from happening, but certainly it will reduce the severity of injury.
We have mandatory PPE and job specific PPE. Mandatory PPEs are required for people entering the plant including the visitors. Mandatory PPEs are safety shoes, safety helmet with chinstrap, safety goggles and high visibility waist jacket. Then comes PPE for specific jobs, like for a worker working at more than 1.8 meters height should have a full body harness with shock absorber with a double lanyard. For gas cutting, safety goggles, apron, hand gloves. For welding work, welders face shield, apron, leg guard, hand gloves. Similarly, we have implemented specific PPEs for every work that is being done at our factory.

Do hazards often happen in a cement plant or are they a rarity?
In all our plants we have a plant safety advisor. When the plant is in operation, a process related hazard can happen in rare occasions, however, any individual can unknowingly initiate the unsafe act giving rise to an incident.
To perform any maintenance work, ‘Permit to Work’ needs to be obtained from the authorized personnel. Before closing the permit, it must be ensured that all equipment guards and Protections are in place. If that is missed, it can give rise to a hazard. If any safety cardinal rules violation observed in the plant, a warning letter is issued to the concerned engineer/manager to correct his behavior and to prevent repeat occurrence of similar major hazards in future.

What are major health concerns cement plant employees face as an occupational hazard?
Cement industry plays a vital role in development of the country and create employment opportunities. Adding to it, safe workplace in cement industry is also one of the important factors to prevent occupational health diseases.
Cement plant workers are exposed to different types of hazards such as fume, gas, and dust which are risk factors to developing occupational diseases. The manufacturing units of a cement factory such as raw mill, preheater, kiln, coal mill, cement mill, cement storage silos, cement packaging section are point sources of pollution or dust emission. Exposure to cement dust leads to respiratory issues, also affecting skin and eyes. It also depends on the duration of a person exposed in the dust.
However, we as a responsible corporate ensure utmost care for our employees by ensuring proper use of PPEs along with installation of proper dust / fume / gas controlling equipment’s. We believe that all employees should come smiling to our establishment should go back home smiling.

Tell us about the key precautions one must take while working in the cement plants to avoid the occupational hazards.
We should have efficient dust control system at source to collect the dust (an engineering control method) i.e. baghouse dust collector, electrostatic precipitator (ESP) and a belt conveyer hood suppression system, water sprinkling on roads and ensuring good housekeeping on regular basis to control dust and to prevent occupational health diseases. These are some of the systems that all cement plants will have to prevent dust emission.
These must be maintained on regular basis to keep them in good working order and conduct air monitoring to measure worker exposures and ensure that controls are providing adequate protection to workers. Not only maintaining the system but we also have to measure the level of dust in the plant ensuring it is with in the statutory limit. If it exceeds the limit, actions must be taken to reduce the emission in the factory. As the last defense, we must provide and ensure the usage of suitable dust masks for all the workers for preventing the dust inhalation.

Can you tell us about a safety issue that occurred in any of your plants and how was it managed?
A workman used to stand on the top of the truck for doing tarpaulin to cover them post loading and removing the tarpaulin for unloading which bring raw materials to the factory. This involves risk of the workman slipping and falling from height. To eliminate this risk, we have provided safe access platforms with fall protection arrangement at all our plants. There would be a platform with a staircase, from where access is provided to the truck top, and from the center point we have given a lifeline across the truck with a full body harness to the workers.

What are the safety trainings provided to your employees? Could take us through
the process?
For all new employees and workmen joining the organization, we have a safety induction training module that covers all the safety rules and regulations of the plant. We also have a safety movie, shot in our own plant, that we show to our workers during safety induction training before issuing them a plant entry gate pass.
For work at height jobs, we conduct height phobia test to ensure that the worker doesn’t have a fear during working at heights. We have a mock structure where a workman is sent to a height and his blood pressure is checked before going up and after coming down. The doctor tells us with his blood pressure if they have passed the test. Those who pass are given the height work pass.
Training on safety behavior and training on lockout, tagout, tryout which is an electrical isolation work permit system, training on confined space, safety toolbox before starting the job, job specific training, firefighting training, training on safety standards etc. We have group safety standards for work at height, confined space work, electrical isolation (LOTOTO) and machine guarding.

Tell us about some of the good safety practices implemented in your HC India plants?
Occupational health and safety are the core value of our company and safety is at the center of everything that we do-from the daily routines in our plants. We are desired to conduct our business with “Zero Harm” to the people we work with and we strive to create a healthy and safe work environment for all our employees, contractors, and stakeholders. We believe that we are good in safety and we are good in
achieving new milestones in business. Safety is a critical success factor for all operational performance and is integrated in all business decisions including greenfield and brownfield projects and employee performance evaluation.

Safety cardinal rules

There are “Safety Cardinal Rules” that all employees and contractors working with us must comply and follow:
All personal protective equipment (PPE) required for a given task must be properly used.
Equipment must be properly isolated from all inherent energy sources and must be tested to ensure it cannot start or move prior to conducting any task.
Safeguards must be in place before the equipment is started or restarted.
Entry into confined spaces is only allowed for competent persons and with a permit to work signed by the responsible superior.
All occupational incidents are reported and investigated to identify the root causes and to set up corrective actions and lessons learned.
Driving for the company is done in strict accordance with the local laws and company requirements.

Monthly safety theme
We have a monthly safety theme launching system. Across all plants, on the first day of each month, respective plant manager launches the theme for the month between a gathering of workers. The catalogue gives details of the risk, it causes, and mitigation measures is printed in a regional language and distributed to all workers. The aim is to see that every relevant worker gets covered and made aware of the risks and mitigating measures. Benefits noticed from the monthly safety theme program from all plants is rise in safety awareness among the workers on the potential risk and mitigation measures.

Plant Safety Star Award Programme:
Plant Safety Star Award programme is unique to HC India initiated by the people and for the people. It identifies people having high regard for safety and are role models for others. Plant safety stars are selected from the workman level through the process of nomination followed by written examination covering topics related to health and safety rules and regulations. The nominations are done by fellow workman, and the one who secures maximum score is declared the Safety Star of the plant in the given trimester. Attractive gifts and award are presented to the winner by Managing Director and Director Technical in presence of all the workforce in the plant and address the gathering to motivate and enhancing the safety culture.

Safety zone system:
HC India encourages employee engagement where they achieve the sense of pride for having shouldered the responsibility of ensuring that everyone returns home safely to be with their loved ones. The entire plant is divided into zones depending on site conditions considering its layout, activities performed, ease of accessibility and monitoring. For each zone a head is chosen who selects representatives from all departments located in the safety zone headed by him. The area under each zone is further divided and allotted to each member responsible for specified section. By such divisions, communication will be more effective with a sense to communicate the hazards and risks to all the people in the zone. Increase the level of safety awareness and identify unsafe behavior to ensure compliance to best safety practices, highlight the near misses, incidents and share the learning, improve and sustain good housekeeping practices. So, the safety zone system is very effective in case of maintaining good housekeeping in the plant. Our tagline is, ‘Someone is waiting for you at home’.

What is the role of technology and automation in safeguarding the cement making process?
Considering the safety aspect, safety interlock switches are used to prevent machine operation or start up in an unsafe situation. Like, the guard is provided with interlock switch, equipment will stops working if the rotating part guard is open.

How frequently does you plant have safety audits and who does them?
All our manufacturing plants are certified under ISO 45001-2018 Occupational health and safety management system certified by TUV SUD South Asia Private limited. The safety audits are conducted by TUV external auditors once in a year and by an internal auditor once in 6 months. Also, in all the plants safety inspections are conducted by Head Safety once in three months. Daily, plant safety advisors carry out plant safety inspections in order to observe the physical conditions of work and the work practices / procedures followed by the workers. The safety advisors also render advice on measures to be adopted for removing unsafe physical conditions while at the same time preventing unsafe actions by workers and apprise the same to the factory manager on regular basis.

-Kanika Mathur

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Concrete

Refractory demands in our kiln have changed

Published

3 days ago

February 20, 2026

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Radha Singh, Senior Manager (P&Q), Shree Digvijay Cement, points out why performance, predictability and life-cycle value now matter more than routine replacement in cement kilns.

As Indian cement plants push for higher throughput, increased alternative fuel usage and tighter shutdown cycles, refractory performance in kilns and pyro-processing systems is under growing pressure. In this interview, Radha Singh, Senior Manager (P&Q), Shree Digvijay Cement, shares how refractory demands have evolved on the ground and how smarter digital monitoring is improving kiln stability, uptime and clinker quality.

How have refractory demands changed in your kiln and pyro-processing line over the last five years?
Over the last five years, refractory demands in our kiln and pyro line have changed. Earlier, the focus was mostly on standard grades and routine shutdown-based replacement. But now, because of higher production loads, more alternative fuels and raw materials (AFR) usage and greater temperature variation, the expectation from refractory has increased.
In our own case, the current kiln refractory has already completed around 1.5 years, which itself shows how much more we now rely on materials that can handle thermal shock, alkali attack and coating fluctuations. We have moved towards more stable, high-performance linings so that we don’t have to enter the kiln frequently for repairs.
Overall, the shift has been from just ‘installation and run’ to selecting refractories that give longer life, better coating behaviour and more predictable performance under tougher operating conditions.

What are the biggest refractory challenges in the preheater, calciner and cooler zones?
• Preheater: Coating instability, chloride/sulphur cycles and brick erosion.
• Calciner: AFR firing, thermal shock and alkali infiltration.
• Cooler: Severe abrasion, red-river formation and mechanical stress on linings.
Overall, the biggest challenge is maintaining lining stability under highly variable operating conditions.

How do you evaluate and select refractory partners for long-term performance?
In real plant conditions, we don’t select a refractory partner just by looking at price. First, we see their past performance in similar kilns and whether their material has actually survived our operating conditions. We also check how strong their technical support is during shutdowns, because installation quality matters as much as the material itself.
Another key point is how quickly they respond during breakdowns or hot spots. A good partner should be available on short notice. We also look at their failure analysis capability, whether they can explain why a lining failed and suggest improvements.
On top of this, we review the life they delivered in the last few campaigns, their supply reliability and their willingness to offer plant-specific custom solutions instead of generic grades. Only a partner who supports us throughout the life cycle, which includes selection, installation, monitoring and post-failure analysis, fits our long-term requirement.

Can you share a recent example where better refractory selection improved uptime or clinker quality?
Recently, we upgraded to a high-abrasion basic brick at the kiln outlet. Earlier we had frequent chipping and coating loss. With the new lining, thermal stability improved and the coating became much more stable. As a result, our shutdown interval increased and clinker quality remained more consistent. It had a direct impact on our uptime.

How is increased AFR use affecting refractory behaviour?
Increased AFR use is definitely putting more stress on the refractory. The biggest issue we see daily is the rise in chlorine, alkalis and volatiles, which directly attack the lining, especially in the calciner and kiln inlet. AFR firing is also not as stable as conventional fuel, so we face frequent temperature fluctuations, which cause more thermal shock and small cracks in the lining.
Another real problem is coating instability. Some days the coating builds too fast, other days it suddenly drops, and both conditions impact refractory life. We also notice more dust circulation and buildup inside the calciner whenever the AFR mix changes, which again increases erosion.
Because of these practical issues, we have started relying more on alkali-resistant, low-porosity and better thermal shock–resistant materials to handle the additional stress coming from AFR.

What role does digital monitoring or thermal profiling play in your refractory strategy?
Digital tools like kiln shell scanners, IR imaging and thermal profiling help us detect weakening areas much earlier. This reduces unplanned shutdowns, helps identify hotspots accurately and allows us to replace only the critical sections. Overall, our maintenance has shifted from reactive to predictive, improving lining life significantly.

How do you balance cost, durability and installation speed during refractory shutdowns?
We focus on three points:
• Material quality that suits our thermal profile and chemistry.
• Installation speed, in fast turnarounds, we prefer monolithic.
• Life-cycle cost—the cheapest material is not the most economical. We look at durability, future downtime and total cost of ownership.
This balance ensures reliable performance without unnecessary expenditure.

What refractory or pyro-processing innovations could transform Indian cement operations?
Some promising developments include:
• High-performance, low-porosity and nano-bonded refractories
• Precast modular linings to drastically reduce shutdown time
• AI-driven kiln thermal analytics
• Advanced coating management solutions
• More AFR-compatible refractory mixes

These innovations can significantly improve kiln stability, efficiency and maintenance planning across the industry.

Concrete

Digital supply chain visibility is critical

Published

3 days ago

February 20, 2026

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MSR Kali Prasad, Chief Digital and Information Officer, Shree Cement, discusses how data, discipline and scale are turning Industry 4.0 into everyday business reality.

Over the past five years, digitalisation in Indian cement manufacturing has moved decisively beyond experimentation. Today, it is a strategic lever for cost control, operational resilience and sustainability. In this interview, MSR Kali Prasad, Chief Digital and Information Officer, Shree Cement, explains how integrated digital foundations, advanced analytics and real-time visibility are helping deliver measurable business outcomes.

How has digitalisation moved from pilot projects to core strategy in Indian cement manufacturing over the past five years?
Digitalisation in Indian cement has evolved from isolated pilot initiatives into a core business strategy because outcomes are now measurable, repeatable and scalable. The key shift has been the move away from standalone solutions toward an integrated digital foundation built on standardised processes, governed data and enterprise platforms that can be deployed consistently across plants and functions.
At Shree Cement, this transition has been very pragmatic. The early phase focused on visibility through dashboards, reporting, and digitisation of critical workflows. Over time, this has progressed into enterprise-level analytics and decision support across manufacturing and the supply chain,
with clear outcomes in cost optimisation, margin protection and revenue improvement through enhanced customer experience.
Equally important, digital is no longer the responsibility of a single function. It is embedded into day-to-day operations across planning, production, maintenance, despatch and customer servicing, supported by enterprise systems, Industrial Internet of Things (IIoT) data platforms, and a structured approach to change management.

Which digital interventions are delivering the highest ROI across mining, production and logistics today?
In a capital- and cost-intensive sector like cement, the highest returns come from digital interventions that directly reduce unit costs or unlock latent capacity without significant capex.
Supply chain and planning (advanced analytics): Tools for demand forecasting, S&OP, network optimisation and scheduling deliver strong returns by lowering logistics costs, improving service levels, and aligning production with demand in a fragmented and regionally diverse market.
Mining (fleet and productivity analytics): Data-led mine planning, fleet analytics, despatch discipline, and idle-time reduction improve fuel efficiency and equipment utilisation, generating meaningful savings in a cost-heavy operation.
Manufacturing (APC and process analytics): Advanced Process Control, mill optimisation, and variability reduction improve thermal and electrical efficiency, stabilise quality and reduce rework and unplanned stoppages.
Customer experience and revenue enablement (digital platforms): Dealer and retailer apps, order visibility and digitally enabled technical services improve ease of doing business and responsiveness. We are also empowering channel partners with transparent, real-time information on schemes, including eligibility, utilisation status and actionable recommendations, which improves channel satisfaction and market execution while supporting revenue growth.
Overall, while Artificial Intelligence (AI) and IIoT are powerful enablers, it is advanced analytics anchored in strong processes that typically delivers the fastest and most reliable ROI.

How is real-time data helping plants shift from reactive maintenance to predictive and prescriptive operations?
Real-time and near real-time data is driving a more proactive and disciplined maintenance culture, beginning with visibility and progressively moving toward prediction and prescription.
At Shree Cement, we have implemented a robust SAP Plant Maintenance framework to standardise maintenance workflows. This is complemented by IIoT-driven condition monitoring, ensuring consistent capture of equipment health indicators such as vibration, temperature, load, operating patterns and alarms.
Real-time visibility enables early detection of abnormal conditions, allowing teams to intervene before failures occur. As data quality improves and failure histories become structured, predictive models can anticipate likely failure modes and recommend timely interventions, improving MTBF and reducing downtime. Over time, these insights will evolve into prescriptive actions, including spares readiness, maintenance scheduling, and operating parameter adjustments, enabling reliability optimisation with minimal disruption.
A critical success factor is adoption. Predictive insights deliver value only when they are embedded into daily workflows, roles and accountability structures. Without this, they remain insights without action.

In a cost-sensitive market like India, how do cement companies balance digital investment with price competitiveness?
In India’s intensely competitive cement market, digital investments must be tightly linked to tangible business outcomes, particularly cost reduction, service improvement, and faster decision-making.
This balance is achieved by prioritising high-impact use cases such as planning efficiency, logistics optimisation, asset reliability, and process stability, all of which typically deliver quick payback. Equally important is building scalable and governed digital foundations that reduce the marginal cost of rolling out new use cases across plants.
Digitally enabled order management, live despatch visibility, and channel partner platforms also improve customer centricity while controlling cost-to-serve, allowing service levels to improve without proportionate increases in headcount or overheads.
In essence, the most effective digital investments do not add cost. They protect margins by reducing variability, improving planning accuracy, and strengthening execution discipline.

How is digitalisation enabling measurable reductions in energy consumption, emissions, and overall carbon footprint?
Digitalisation plays a pivotal role in improving energy efficiency, reducing emissions and lowering overall carbon intensity.
Real-time monitoring and analytics enable near real-time tracking of energy consumption and critical operating parameters, allowing inefficiencies to be identified quickly and corrective actions to be implemented. Centralised data consolidation across plants enables benchmarking, accelerates best-practice adoption, and drives consistent improvements in energy performance.
Improved asset reliability through predictive maintenance reduces unplanned downtime and process instability, directly lowering energy losses. Digital platforms also support more effective planning and control of renewable energy sources and waste heat recovery systems, reducing dependence on fossil fuels.
Most importantly, digitalisation enables sustainability progress to be tracked with greater accuracy and consistency, supporting long-term ESG commitments.

What role does digital supply chain visibility play in managing demand volatility and regional market dynamics in India?
Digital supply chain visibility is critical in India, where demand is highly regional, seasonality is pronounced, and logistics constraints can shift rapidly.
At Shree Cement, planning operates across multiple horizons. Annual planning focuses on capacity, network footprint and medium-term demand. Monthly S&OP aligns demand, production and logistics, while daily scheduling drives execution-level decisions on despatch, sourcing and prioritisation.
As digital maturity increases, this structure is being augmented by central command-and-control capabilities that manage exceptions such as plant constraints, demand spikes, route disruptions and order prioritisation. Planning is also shifting from aggregated averages to granular, cost-to-serve and exception-based decision-making, improving responsiveness, lowering logistics costs and strengthening service reliability.

How prepared is the current workforce for Industry 4.0, and what reskilling strategies are proving most effective?
Workforce preparedness for Industry 4.0 is improving, though the primary challenge lies in scaling capabilities consistently across diverse roles.
The most effective approach is to define capability requirements by role and tailor enablement accordingly. Senior leadership focuses on digital literacy for governance, investment prioritisation, and value tracking. Middle management is enabled to use analytics for execution discipline and adoption. Frontline sales and service teams benefit from
mobile-first tools and KPI-driven workflows, while shop-floor and plant teams focus on data-driven operations, APC usage, maintenance discipline, safety and quality routines.
Personalised, role-based learning paths, supported by on-ground champions and a clear articulation of practical benefits, drive adoption far more effectively than generic training programmes.

Which emerging digital technologies will fundamentally reshape cement manufacturing in the next decade?
AI and GenAI are expected to have the most significant impact, particularly when combined with connected operations and disciplined processes.
Key technologies likely to reshape the sector include GenAI and agentic AI for faster root-cause analysis, knowledge access, and standardisation of best practices; industrial foundation models that learn patterns across large sensor datasets; digital twins that allow simulation of process changes before implementation; and increasingly autonomous control systems that integrate sensors, AI, and APC to maintain stability with minimal manual intervention.
Over time, this will enable more centralised monitoring and management of plant operations, supported by strong processes, training and capability-building.

Concrete

Cement Additives for Improved Grinding Efficiency

Published

3 days ago

February 20, 2026

admin

Shreesh A Khadilkar discusses how advanced additive formulations allow customised, high-performance and niche cements—offering benefits while supporting blended cements and long-term cost and carbon reduction.

Cement additives are chemicals (inorganic and organic) added in small amounts (0.01 per cent to 0.2 per cent by weight) during cement grinding. Their main job? Reduce agglomeration, prevent pack-set, and keep the mill running smoother. Thus, these additions primarily improve, mill thru-puts, achieve lower clinker factor in blended cements PPC/PSC/PCC. Additionally, these additives improve concrete performance of cements or even for specific special premium cements with special USPs like lower setting times or for reduced water permeability in the resultant cement mortars and concrete (water repellent /permeation resistant cements), corrosion resistance etc.
The cement additives are materials which could be further differentiated as:

Grinding aids:
• Bottlenecks in cement grinding capacity, such materials can enhance throughputs
• Low specific electrical energy consumption during cement grinding
• Reduce “Pack set” problem and improve powder flowability

Quality improvers:
• Opportunity for further clinker factor reduction
• Solution for delayed cement setting or strength development issues at early or later ages.

Others: materials which are used for specific special cements with niche properties as discussed in the subsequent pages.
When cement additives are used as grinding aids or quality improvers, in general the additives reduce the inter-particle forces; reduce coating over grinding media and mill internals. Due to creation of like charges on cement particles, there is decreased agglomeration, much improved flowability, higher generation of fines better dispersion of particles in separator feed and reduction of mill filling level (decrease of residence time). However, in VRM grinding; actions need to be taken to have stable bed formation on the table.
It has been reported in literature and also substantiated by a number of detailed evaluations of different cement additive formulations in market, that the cement additive formulations are a combination of different chemical compounds, typically composed of:

Accelerator/s for the hydration reaction of cements which are dependent on the acceleration effect desired in mortar compressive strengths at early or later ages, the choice of the materials is also dependent on clinker quality and blending components (flyash / slag) or a mix of both.
Water reducer / workability / wet-ability enhancer, which would show impact on the resultant cement mortars and concrete. Some of the compounds (retarders) like polysaccharide derivatives, gluconates etc., show an initial retarding action towards hydration which result in reducing the water requirements for the cements thus act as water reducers, or it could be some appropriate polymeric molecules which show improved wet-ability and reduce water demand. These are selected based on the mineral component and type of cements (PPC/PSC /PCC).
Grinding aids: Compounds that work as Grinding Aid i.e. which would enhance Mill thru-put on one hand as well as would increase the early strengths due to the higher fines generation/ or activation of cement components. These compounds could be like alkanol-amines such as TIPA, DEIPA, TEA etc. or could be compounds like glycols and other poly-ols, depending on whether it is OPC or PPC or PSC or PCC manufacture.

Mechanism of action — Step By Step—

Reduce Agglomeration, Cement particles get electrostatically charged during grinding, stick together, form “flocs”, block mill efficiency, waste energy. Grinding aid molecules adsorb onto particle surfaces, neutralise charge, prevent re-agglomeration.
Improve Powder Flowability, Adsorbed molecules create a lubricating layer, particles slide past each other easier, better mill throughput, less “dead zone” buildup.
Also reduces caking on mill liners, diaphragms, and separator screens, less downtime for cleaning.
Enhance Grinding Efficiency (Finer Product Faster), By preventing agglomeration, particles stay dispersed more surface area exposed to grinding media, finer grind achieved with same energy input, Or: same fineness achieved with less energy, huge savings.
Example:
• Without aid ? 3500 cm²/g Blaine needs 40 kWh/ton
• With use of optimum grinding aid same fineness at 32 kWh/ton 20 per cent energy savings
Reduce Pack Set and Silo Caking Grinding aids (GA) inhibit hydration of free lime (CaO) during storage prevents premature hardening or “pack set” in silos. especially critical in humid climates or with high free lime clinker.
It may be stated here that Overdosing of GA can cause: – Foaming in mill (especially with glycols) reduces grinding efficiency, retardation of cement setting (especially with amines/acids), odor issues (in indoor mills) – Corrosion of mill components (if acidic aids used improperly)
The best practice to optimise use of GA is Start with 0.02 per cent to 0.05 per cent dosage test fineness, flow, and set time adjust up/down. Due to static charge of particles, the sample may stick to the sides of sampler pipe and so sampling need to be properly done.
Depending on type of cements i.e. OPC, PPC, PSC, PCC, the grinding aids combinations need to be optimised, a typical Poly carboxylate ether also could be a part of the combo grinding aids

Cement additives for niche properties of the cement in concrete.
The cement additives can also be tailor made to create specific niche properties in cements, OPC, PPC, PSC and PCC to create premium or special brands. The special niche properties of the cement being its additional USP of such cement products, and are useful for customers to build a durable concrete structure with increased service life.

Such properties could be:
• Additives for improved concrete performance of cements, high early strength in PPC/PSC/PCC, much reduced water demand in cement, cements with improved slump retentivity in concrete, self-compacting, self levelling in concrete, cements with improved adhesion property of the cement mortar
• Water repellence / water proofing, permeability resistance in mortars and concrete.
• Biocidal cement
• Photo catalytic cements
• Cements with negligible ASR reactions etc.

Additives for cements for improved concrete performance
High early strengths: Use of accelerators. These are chemical compounds which enhance the degree of hydration of cement. These can include setting or hardening accelerators depending on whether their action occurs in the plastic or hardened state respectively. Thus, the setting accelerators reduce the setting time, whereas the hardening accelerators increase the early age strengths. The setting accelerators act during the initial minutes of the cement hydration, whereas the hardening accelerators act mainly during the initial days of hydration.
Chloride salts are the best in class. However, use of chloride salts as hardening accelerators are strongly discouraged for their action in promoting the corrosion of rebar, thus, chloride-free accelerators are preferred. The hardening accelerators could be combinations of compounds like nitrate, nitrite and thiocyanate salts of alkali or alkaline earth metals or thiosulphate, formate, and alkanol amines depending on the cement types.
However, especially in blended cements (PPC/PSC/PCC the increased early strengths invariably decrease the 28 day strengths. These aspects lead to creating combo additives along with organic polymers to achieve improved early strengths as well as either same or marginally improved 28 days strengths with reduced clinker factor in the blended cement, special OPC with reduced admixture requirements. With use of appropriate combination of inorganic and organic additives we could create an OPC with substantially reduced water demand or improved slump retentivity. Use of such an OPC would show exceptional concrete performance in high grade concretes as it would exhibit lower admixture requirements in High Grade Concretes.
PPC with OPC like properties: With the above concept we could have a PPC, having higher percentage flyash, with a combo cement additive which would have with concrete performance similar to OPC in say M40/M50 concrete. Such a PPC would produce a high-strength PPC concrete (= 60 MPa @ 28d) + improved workability, durability and sustainability.
Another interesting aspect could also be of using ultrafine fine flyash /ultrafine slags as additions in OPC/PPC/PSC for achieving lower clinker factor as well as to achieve improved later age strengths with or without a combo cement additive.
The initial adhesion property at sites of especially PPC/PSC/PCC based mortars can be improved through use of appropriate organic polymers addition during the manufacture of these cements. Such cements would have a better adhesion property for plastering/brick bonding etc., as it has much lower rebound loss of their mortars in such applications.
It is needless to mention here that with use of additives, we could also have cement with viscosity modifying cement additives, for self-compaction and self-leveling concrete performance.
Use of Phosphogypsum retards the setting time of cements, we can use additive different additive combos to overcome retardation and improve the 1 day strengths of the cements and concretes.

About the author:
Shreesh Khadilkar, Consultant & Advisor, Former Director Quality & Product Development, ACC, a seasoned consultant and advisor, brings over 37 years of experience in cement manufacturing, having held leadership roles in R&D and product development at ACC Ltd. With deep expertise in innovative cement concepts, he is dedicated to sharing his knowledge and improving the performance of cement plants globally.