Concrete

Concrete repair and corrosion control

Published

14 years ago

April 30, 2012

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Corrosion of concrete happens due to various factors but it is necessary to repair the damage caused by such corrosion. In Part-1 of the two-part series, Upen Patel, Business Director, BASF India, dwells at length on the causes of deterioration and the remedy thereofOnce concrete repairs and strengthening was considered as an activity of rejuvenating the old structures and making them capable of loadings and environmental stresses in the future life. Today we are constructing more advanced and ever more-demanding structures with complex detailing and concrete repairs and strengthening starts during the construction stage itself. The complex and fast pace construction methods with reduced emphasis on adequate quality assurance results in to construction errors and creates needs for repairs and strengthening during construction. With the complex performance demands of the new structures and ever longer life expectancies makes concrete repairs, strengthening and protection procedures more and more demanding. This article is an attempt to present the fundamentals of concrete repairs and strengthening in a step-by-step process and focuses on the advantages and disadvantages of current practices and provides an insight in the futuristic but more simple to adopt techniques.Basic DefinitionsRepairs: To replace or correct deteriorated, damaged or faulty materials, components or elements of a concrete structure.Strengthening: The process of restoring the capacity of weakened components or elements to their original design capacity or increasing the strength of components or elements of a concrete structure.Protection: Making the structure capable to resist the likely deterioration due to the surrounding/ environment.Why concrete needs repairs?There are many factors which lead to the need of repairs such as:??Corrosion of reinforcement due to carbonation, chlorides??Sulphates??Alkali silica reaction??Environmental pollution??Deicing salts??Acid rains??Marine environment??Oils??Freeze thaw cycles??Abrasion or erosion from wind or water borne agents??Plants or microorganisms??Overloading??Physical settlement??Impact??Earthquake??Fire??Chemical attack by aggressive chemicals, sewerage or even soft waterAlso the deterioration gets aggravated due to errors/mistakes/poor workmanship during construction such as:??Higher w/c ratio??Honeycombs and compaction voids??Bleeding and segregation??Plastic shrinkages and hardening stage shrinkage cracks??Inadequate or no curing??In sufficient concrete cover??Cast-in chlorides from contaminated water/aggregates??Inadequate or excessive vibration during the concerting??Shutterwork or reinforcement movement during placement of concreteGenerally concrete structure requires repairs in the two events- New construction and during the service life. Repairs in the new construction require different approach then the repairs during service life and we shall deal one by one to better understand. The repairs during service life have more steps and we shall deal with it first. The repairs during service life arise due to certain deterioration taken place and understanding of the same is very vital in the design of the repair solution.Why concrete deteriorates?The reinforced concrete was designed with a basic understanding that its a marriage of two carrying spouses – concrete and steel. Concrete protects steel from getting corroded and steel protects concrete from getting cracked due to bending. The marriage was designed to last forever but the environment facilitates entry of many agents who leads the marriage to divorce…Major agents and their activities are described as under:-Carbonation: The high pH of concrete passivates steel reinforcement from getting corroded. The carbon dioxide / sulphur dioxide present in the atmosphere gets dissolved in the water and forms weak carbonic /sulphuric acid and enters the concrete reducing the pH, resulting in the loss of passivation layer around reinforcement. The reinforcement states getting corroded resulting in to the rust. The rust formed has 4- times the original volume of the metal creating bursting pressure in the concrete mass. The build up of the pressure eventually cracks the concrete and makes the access for ingress of corrosive water and other water dissolved agents easily. The quicker access aggravates the corrosion and structure starts deteriorating rapidly. Spalling of the concrete cover and formation of brown colored rust is a visual indication of the carbonation attack. The carbonation attack can be checked by phenolphthalein liquid. The reaction is at its best at 50-75 % relative humidity.Chloride attack: The main source of chlorides is the contaminated water or aggregates during construction and marine environment – direct contact with sea water or through wind borne chlorides in the splash zone. Chlorides ions are the passivating ferrous oxide layer on the steel reinforcement. Once reinforcement loses its passivation layer, it is highly susceptible to electro-chemical corrosion further induced by chlorides ions. The water dissolved chlorides ions form electro-chemical corrosion cell and establishes anodic and cathodic sites on the re-bar.The electro-chemical corrosion results in to pitting corrosion-reduction in the cross section of the re-bar at specific sites without noticeable deterioration of the concrete cover. The hidden reduction in the cross-section of the reinforcement can results in to sudden failure of the structure member-making this as one of the most dangerous deterioration in the concrete structure. There is no ‘net use’ of chloride ions during the corrosion process. Therefore, once enough chloride ions reach the steel to break the passivation layer only water, oxygen and a conductive medium is needed to maintain the corrosion reaction. Also note that since corrosion is a chemical reaction, temperature plays a role in the process. The higher the temperature the faster the corrosion reaction occurs. The general rule for the rate of chemical reactions is that for every 25 degree F increases, the reaction rate doubles.Sulphate attack: The main source of sulphates is the ground water. The sulphates attack on concrete, by reacting with the C3A in the concrete. The reactive product is larger in the volume resulting in to the expansive cracking in the concrete mass. The spalling and cracking of concrete takes place without any deterioration of the reinforcement to start with. With the time other forms of corrosion such as carbonation, chlorides becomes aggravated due to quicker access to the reinforcement. The sulphate attack can be reduced by using sulphate resistant cement which has low C3A content; but this reduces the resistance of chloride attack and hence no more a preferred option in the marine situation.Alkali-silica reaction (ASR): In the case of ASR the alkali-reactive aggregates forms expansive gels in the concrete structure resulting in to cracking and spalling.Step-by-step process to successful repairs:-Following steps are essential for successful repairs:-??Evaluation??Relating observations to causes??Selecting methods and material for repairs??Preparation of drawings and specifications??Selection of contractor??Execution of the work??Quality control??Preserve records for futureEvaluationEvaluate the current condition of the concrete structure. Structural analysis of the structure in its deteriorated condition, review of records of any previous repair work accomplished, review of maintenance records, visual examination, destructive and noon-destructive testing and lab analysis of concrete samples. Some of the popular tests used during the evaluation are summarised as under:-??Visual inspection and recording??Hammer sounding / Rebound hammer test??Phenolphthalein test for carbonation??Silver-nitrate test for chloride attack??Half-cell potential measurement??Core-cutting??Chemical analysis of concrete at different depthsRepair philosophyIt is most important to consider the full load envelope, which has been acting on the structure during the complete service life and in the future. The repair materials must have compatibility with the existing structure. The compatibility may be defined as a balance (equilibrium) of physical, chemical, electrochemical and dimensional properties between the repair material and the existing substrate in structural exposure conditions for a determined period of time.1st Compatibility: Physical/Permeability??Allow substrate to breath??Prevent entry of water and waterborne salts – Sulphate, Chlorides, SO2, CO2 2nd Compatibility: Chemical??No negative chemical interaction with the substrate??Absence of potentially dangerous substances such as chlorides, alkalies??No expansive ettringite formation of sulphate3rd Compatibility: Electro-chemical??Higher resistance to corrosion current??Must have conductivity and should not isolate substrate??Effective passivation of re-bars4th Compatibility: Dimensional stabilityCoefficient of Thermal Expansion: Different Coefficients of Thermal Expansion causes differential movement and hence shall be avoided.Modules of Elasticity: Under compression materials of different module will cause stress at the interface and hence shall be avoided.Drying shrinkage: Drying shrinkage of fresh mortar causes stresses at interface; hence needs to be controlled to minimum.(Extract from the paper presented by the author at the Construction Chemicals International Conference 2012 held in Mumbai)(Extract from the paper presented by the author at the Construction Chemicals International Conference 2012 held in Mumbai)

Concrete

Dalmia Bharat launches Weather 365 in East India

New water-repellent cement targets weather-resilient housing demand

Published

3 hours ago

May 15, 2026

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Dalmia Bharat Cement has launched Weather 365, a super-premium water-repellent cement brand for retail markets in West Bengal and Bihar. The product is designed to address rising demand for durable and weather-resistant construction materials in Eastern India.

Weather 365 offers protection against seepage, dampness and moisture damage, especially in regions exposed to heavy rainfall, humidity and changing weather cycles. The cement is suited for roofs, columns and foundations, and uses uniform water-repellent technology to reduce water penetration, steel corrosion, efflorescence and damp patches.

The company said the product will be available in water-resistant and tamper-proof BOPP packaging. It will also provide on-site technical support through engineering and technical services teams to guide customers on construction practices and long-term building performance.

Positioned in Dalmia Bharat Cement’s premium portfolio, Weather 365 targets homeowners, contractors and builders seeking stronger concrete, improved paint life and better structural durability. The launch supports the company’s strategy to expand premium construction solutions in key Eastern India markets.

Concrete

Filtration Technology is Critical for Efficient Logistics

Published

6 hours ago

May 15, 2026

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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.

Concrete

Cement’s Next Fuel Shift

Published

8 hours ago

May 15, 2026

admin

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.