Concrete

Concrete Temperature

Published

9 years ago

July 31, 2017

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RUPESH KUMAR explains why it is important to control concrete temperature and how it can be done.
With mega structures coming up every?where using high-grade concrete, the control of concrete temperature is become a matter of frequent discu?ssion among civil engineers.

The concern
Green concrete, the nascent stage of concrete hardening, requires a lot of care to mature as good concrete. Concrete is weak in tension bearing; more so, in the initial stage of hardening. Its vulnerability becomes more critical when there are tensile forces induced owing to the hardening process. Being an exothermic reaction, heat is generated during the process; this causes thermal differential and stress that act as a tensile force and cause cracks.

In many cases, cracks developed at the initial stages do not heal and remain or widen further as the concrete shrinks during further hardening. This leads to a situation where structural stability, integrity and durability begin to get compromised. The following observations can be made in the early days of concrete, primarily in the first week:

Concrete matures with time and temperature.
Strength comes with maturity.
In seven days, almost 2/3 of 28 days strength gain for OPC cement-based concrete is expected, though this can vary according to the design mix.
The exothermic chemical reaction is most active during this period.
Thermal gain is achieved to its maximum during this period; concrete core temperature starts declining after reaching its peak in most cases.
Core temperature rise causes thermal differential and stress in concrete.
The higher the temperature, faster the maturity. But early higher temperature leads to a greater tendency to crack internally, owing to higher thermal stress. Increasing temperature in the early days has shown more strength on the seventh day and less on day 28 compared to standard maturity of concrete on day seven and 28 respectively, owing to thermal micro-cracking.
Concrete plastic shrinkage and initial shrinkage are more dominant during this period and slow down with time. Late shrinkage can continue for many months but the effect is not so significant as the concrete strength is able to counteract the stress of late shrinkage in most cases.
Cracks developed during the initial stage owing to plastic shrinkage may not heal automatically in further maturity. On the contrary, at times the crack increases in width, depth or both with time, owing to shrinkage stress acting as a localised tensile force.
Cracks develop when the tensile stress increases more than the tensile bearing capacity of the concrete.
If the concrete does not gain sufficient strength during the peak concrete temperature, and specifically during higher thermal differential, there is higher likelihood of cracking.
The peak temperature of concrete and the thermal differential depends on the green concrete temperature as well as the ambient temperature along with shuttering (temporary formwork) condition.
The heat gain in the concrete for a given design mix is the same; thus, the green concrete has a direct effect on the heat gain and rise in concrete core temperature. The higher the green concrete temperature, higher the core peak temperature, and vice versa.
The thermal differential causes the stress in the concrete and core to the surface temperature of the concrete must be kept in controlled condition to control the differential. However, the peak temperature of the core beyond a limit may cause other long-term effects like DEF (delayed ettringite formation; a matter yet to be ascertained codally) and needs to be addressed. In Indian tropical conditions, DEF is not expected to be of serious concern if the temperature is taken care of to limit peak temperature below 70?and pozzolanic material is used in the mix. However, thermal differential of concrete must be an area of focus for durable concrete.

Green concrete temperature
The temperature control limits of green concrete are specified in various codes and they all vary. There are references for RCC green concrete temperature for below 40?, up to 38? up to 32?, up to 30? and up to 25? in various codes, including BIS, BS and ASTM.

With higher grades of concrete, the maximum allowable core temperature restrictions are of higher consideration, which restrict the green concrete temperature less than what is allowed in the codes.

To restrict the peak temperature, the green concrete temperature is asked to be reduced. In such a specific scenario, a holistic approach should be taken to define the green concrete temperature as lowering the temperature is a costly affair – although it is not intended to compromise the strength and durability of the concrete. Care should be taken as green concrete temperature control requires a broader approach than simply lowering the temperature during production; it should first be ascertained whether it is really required. It is more prudent to have higher temperature rather than more thermal differential. Also, the lower temperature should be sustained – not less at any one stage of the concrete production, transportation, placement and construction. Further, thermal consideration of concrete is more important for mass concrete than smaller sections.

Way to set concrete temperature limit
To understand the thermal consideration for a given concrete in a project, a preliminary test should be done to arrive at the initial data. Except generally established limits, at present, the codes have not established the procedure for review and analysis of concrete temperature acceptance for a given scenario. A procedure with the action points mentioned below can be used to logically arrive at a calculation analysis and mock-up review to arrive at the concrete temperature acceptance for the given scenario. Some important questions to ask during calculation analysis and mock-up testing are:

How does the concrete temperature rise with time and when the peak temperature is reached for a given mix? For this, a thermal probe can be inserted before placing the concrete and recoding can be done using a thermal data logger. Alternatively, manual set-up and reading can be done, but manual recoding is tedious. The data can be recorded or plotted and analysed.

What is the design calculation with consideration of thermal stress and the crack width allowed as per the design? The data can be obtained from the design calculation sheet or designer.

How is the reinforcement as per the design of the structure and is it able to take the stress developed in the concrete owing to thermal stress? The designer can confirm this and reinforcement adequacy for taking additional thermal stress can be checked considering the crack width limitation as per the design calculation.

How is the maturity of concrete and subsequently the strength of concrete with respect to time? The data can be obtained by taking additional sufficient concrete samples and keeping them under standard testing condition. Curing tank temperature can be taken if the temperature is not being maintained in the curing tank. Testing of concrete sampling shall be done as per testing the procedure at various durations.

Is there any crack observed in the mock up and is there is any crack owing to thermal stress and not plastic shrinkage? To avoid plastic shrinkage, the mock shall preferably be for an adiabatic condition for unreinforced, 1 cu m of mass or miniature replica of the actual structure.

Close observation is required to check crack development; if required, a core can be taken to check the inside of the concrete mass. Normally, thermal stress if developed and causing a crack inside, will reflect up to the surface as the surface to core thermal differential is expected to be more than the thermal differential of the core to the other inner part of concrete. Based on a visual examination, the cracks can be checked.

Now, based on the data mentioned above, one can calculate the estimated concrete temperature and acceptable thermal differential. It can also be analysed whether the concrete is expected to crack beyond the design calculation for the given reinforcement design and estimated concrete peak temperature in the project ambient temperature, and more so for the thermal differential. Then, verification can be done by examining the mock-up concrete.

Thus, one can ascertain whether concrete can sustain the expected peak temperature and thermal differential for a given design mix with reinforcement as per design and ambient condition during construction. In case of non-reinforced concrete (PCC-based structure), reinforcement stress bearing will not be present and the concrete would be able to sustain only as much stress as the maturity of concrete will allow.

About the author
Rupesh Kumar is a Quality Manager and Concrete Technologist with 18 years of experience working in mega projects in India and abroad. He has dealt with more than 2.5 million cu m of concrete in projects of RMC, hospital, factories, stadium, metros, airports and statue.

This artical was first published in Construction World magazine

Concrete

JSW Cement Begins Production At Nagaur Rajasthan Plant

Greenfield integrated cement plant begins operations in Rajasthan

Published

57 minutes ago

March 23, 2026

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JSW Cement has started production at a new greenfield integrated cement plant in Nagaur, Rajasthan, marking its first integrated facility in north India. The commissioning advances its national expansion and raises cement grinding capacity to 24.1 million tonnes per annum (MTPA) and clinker manufacturing capacity to nine point seven four MTPA including joint venture capacity. The plant is strategically located to serve high growth markets in Rajasthan, Haryana, Punjab and the National Capital Region.

The Nagaur plant comprises a three point three MTPA clinkerisation unit and a two point five MTPA cement grinding unit, with an additional one MTPA grinding unit under construction. The facility’s capacity additions enable it to meet regional demand and support infrastructure development. The project was funded by equity and long term debt and the company allocated Rs 8 bn from IPO proceeds to part finance the unit.

Company leadership said commissioning was completed within 21 months and that the expansion advances its aim to become a pan India player, with a mid term target of 41.85 MTPA and a long term vision of 60 MTPA. The plant includes sustainability features such as co processing of alternative fuels and a seven kilometre overland belt conveyor to transport limestone from the mines, reducing road transport impacts. The operation is expected to support economic growth and provide supplies for construction projects across the north.

The site will incorporate a 16 megawatt (MW) Waste Heat Recovery System to capture and reuse process heat, reducing the carbon footprint. JSW Cement’s operations include eight plants in India and a clinker unit in the UAE through a joint venture, providing a presence across the building materials value chain. The company emphasised use of industrial by products in manufacture and focus on producing eco friendly building materials.

Concrete

MAPEI India Celebrates 15 Years of Building Excellence

MAPEI India celebrates 15 years with growth, expansion and CSR impact

Published

57 minutes ago

March 23, 2026

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MAPEI India marks its 15th anniversary, celebrating a journey defined by innovation, trust, and continuous growth. Beginning in 2011 with just four employees and a single manufacturing facility in Bengaluru, the company has evolved into a key player in India’s construction chemicals industry, now employing over 380 professionals across the country. Over the past 15 years, MAPEI India has delivered strong performance with a sales CAGR of 31 per cent. From zero production in its early years, the company shipped 1,71,000 metric tonnes of materials in 2025, demonstrating robust operational capabilities and rising market acceptance.

To support expanding demand, MAPEI India has steadily scaled its manufacturing footprint. Following the Bengaluru plant in 2011, new facilities were launched in Vadodara in 2016 and Kosi (Mathura) in 2022. A fourth facility in Kharagpur is set to go live in 2026, strengthening the company’s nationwide supply network.

As part of its commitment to global standards, MAPEI India operates under an Integrated Management System (IMS) certified for ISO 9001 (Quality), ISO 14001 (Environment) and ISO 45001 (Health & Safety). These certifications reinforce its dedication to delivering safe, sustainable, and high quality solutions.

With a diverse portfolio of over 20 product lines, MAPEI India has supported iconic projects such as the Atal Tunnel, the Statue of Unity, and major airport and metro developments. The company has also invested Rs 3.2 crore in CSR initiatives focused on education, women’s empowerment, and rehabilitation. As it steps into the future, MAPEI India remains committed to excellence, sustainability, and customer trust.

Mapei hai to bharosa hai.

Concrete

Material Flow Efficiency

Published

5 days ago

March 18, 2026

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We explore how material handling systems are becoming strategic assets in cement plants, enabling efficient movement of raw materials, clinker and finished cement. Advanced conveying, automation and digital technologies are improving plant productivity while supporting energy efficiency and sustainability goals.

Material handling systems form the operational backbone of cement plants, enabling the efficient movement of raw materials, clinker and finished cement across complex production networks. With India’s cement industry producing over 391 million tonnes of cement in FY2024 and possessing an installed capacity of around 668 mtpa, according to the CRISIL Research Industry Report, 2025, efficient material logistics have become critical to maintaining plant productivity and cost competitiveness. At the same time, cement production is highly energy intensive and contributes around 7 per cent to
8 per cent of global CO2 emissions, making efficient material flow and logistics optimisation essential for reducing operational inefficiencies and emissions states the International Energy Agency Cement Technology Roadmap, 2023. As plants scale capacity and integrate digital technologies, modern material handling systems, ranging from automated conveyors to intelligent stockyards, are increasingly recognised as strategic assets that influence plant stability, energy efficiency and environmental performance.

Strategic role of material handling
Material handling is no longer viewed as a secondary utility within cement plants; it is now recognised as a strategic system that directly influences production efficiency and process stability.
Cement manufacturing involves the continuous movement of large volumes of limestone, clay, additives, clinker and finished cement across multiple production stages. Even minor disruptions in conveying systems or storage infrastructure can lead to kiln feed fluctuations, production delays and significant financial losses. According to Indian Cement Industry Operational Benchmarking Study, 2024, unplanned downtime in large integrated cement plants can cost between Rs.15–20 lakh per hour, highlighting the economic importance of reliable material handling systems.
Modern cement plants are therefore investing in advanced mechanical handling systems designed for high throughput and operational reliability. Large integrated plants can process over 10,000 tonnes per day of clinker, requiring highly efficient conveying systems and automated stockyards to maintain continuous material flow, suggests the International Cement Review Industry Analysis, 2024. Efficient material handling also reduces spillage, minimises dust emissions and improves workplace safety. As cement plants become larger and more technologically advanced, the role of material handling is evolving from simple transport infrastructure to a critical operational system that supports both productivity and sustainability.

From quarry to plant
The transport of raw materials from quarry to processing plant represents one of the most energy-intensive stages of cement production. Traditionally, limestone and other raw materials were transported using diesel-powered trucks, which resulted in high fuel consumption, dust generation and increased operational costs. However, modern plants are increasingly adopting long-distance belt conveyors and pipe conveyors as a more efficient alternative. These systems allow continuous material transport over distances of 10–15 kilometres, significantly reducing fuel consumption and operating costs while improving environmental performance, states the FLSmidth Cement Industry Technology Report, 2024.
Milind Khangan, Marketing Manager, Vertex Market Research & Consulting, says, “Efficient and enclosed handling of fine materials such as cement, fly ash and slag requires modern pneumatic conveying systems. By optimising the air-to-material ratio, these systems can reduce energy consumption by 10 per cent to 15 per cent while ensuring smooth material flow. Closed-loop conveying further minimises dust loading and improves the performance of bag filters, supporting cleaner plant operations. In addition, flow-regulated conveying lines help prevent clogging and maintain reliable dispatch performance. Overall, automation in pneumatic conveying delivers immediate operational benefits, including improved equipment uptime, lower energy use, reduced material spillage and more stable kiln and mill performance.”
Pipe conveyor systems are particularly gaining traction because they provide a completely enclosed transport system that prevents material spillage and dust emissions. According to global cement engineering studies, conveyor-based transport can reduce energy consumption by up to 30 per cent compared to truck haulage, while also improving operational reliability. Several cement plants in India have already implemented such systems to stabilise quarry-to-plant logistics while reducing carbon emissions associated with diesel transport.

Stockyard management and homogenisation
Stockyards play a critical role in maintaining raw material consistency and stabilising kiln feed quality. Modern cement plants use advanced stacker and reclaimer systems to ensure efficient storage and blending of raw materials before they enter the grinding and pyroprocessing stages. Automated stacking methods such as chevron or windrow stacking enable uniform distribution of materials, while bridge-type or portal reclaimers ensure consistent extraction during kiln feed preparation. These systems are essential for maintaining stable chemical composition of raw meal, which directly influences kiln efficiency and clinker quality. The Cement Plant Operations Handbook, 2024 indicates that advanced homogenisation systems can reduce raw mix variability by up to 50 per cent, significantly improving kiln stability and energy efficiency. Integrated stockyard management systems also incorporate sensors for monitoring bulk density, moisture levels and stockpile volumes, enabling real-time control over material blending processes.

Clinker and cement conveying technologies
Once clinker is produced in the kiln, it must be efficiently transported to storage silos and subsequently to grinding and packing units. Modern cement plants rely on high-capacity belt conveyors, bucket elevators and pneumatic conveying systems to manage this stage of material flow. Steel-cord belt bucket elevators are now capable of lifting materials to heights exceeding 120 metres with capacities reaching 1,500 tonnes per hour, making them suitable for large-scale clinker production lines, states the European Cement Engineering Association Technical Paper, 2023.
For fine materials such as cement, fly ash and slag, pneumatic conveying systems provide a reliable and dust-free solution. These systems transport powdered materials using controlled airflow, ensuring enclosed and contamination-free movement between grinding units, silos and packing stations. Optimised pneumatic systems can reduce energy consumption by 10 per cent to 15 per cent compared to older conveying technologies, while also improving plant cleanliness and environmental compliance, according to the Global Cement Technology Review, 2024.

Automation and digitalisation
Digitalisation is transforming material handling systems by introducing real-time monitoring, predictive maintenance and automated control. Advanced sensors and Industrial Internet of Things (IIoT) platforms enable plant operators to track conveyor health, stockpile levels and equipment performance in real time. Predictive maintenance systems analyse vibration patterns, temperature fluctuations and equipment load data to detect potential failures before they occur. According to McKinsey’s Industry 4.0 Manufacturing Report, 2023, for heavy industries, digital monitoring and predictive maintenance technologies can reduce equipment downtime by up to 30 per cent and increase productivity by 10 per cent to 15 per cent. Digital control centres also integrate data from conveyors, stacker reclaimers and dispatch systems, enabling centralised management of material flows from quarry to dispatch.

Handling of AFR
The growing adoption of Alternative Fuels and Raw Materials (AFR) has introduced new challenges and opportunities for material handling systems in cement plants. AFR materials such as refuse-derived fuel (RDF), biomass and industrial waste often have irregular particle sizes, variable moisture content and lower bulk density compared to conventional fuels. As a result, specialised storage, dosing and feeding systems are required to ensure consistent kiln combustion. According to the Cement Sector Decarbonisation Roadmap published by NITI Aayog in 2026, increasing the use of AFR could enable India’s cement sector to achieve thermal substitution rates of around 20 per cent in the coming decades. To support this transition, plants are investing in automated receiving stations, shredding units, drying systems and precision dosing equipment to stabilise AFR supply and combustion performance.

Energy efficiency and dust control
Material handling systems also play a crucial role in improving plant energy efficiency and environmental performance. Modern conveyor systems equipped with variable speed drives and energy-efficient motors can significantly reduce electricity consumption. Permanent magnet motors used in conveyor drives can deliver 8 per cent to 12 per cent energy savings compared to conventional induction motors, improving overall plant energy efficiency according to the IEA Industrial Energy Efficiency Study, 2023. Dust control is another major concern in cement plants, particularly during material transfer and storage operations. Enclosed conveyors, dust extraction systems and advanced bag filters are widely used to minimise particulate emissions and improve workplace safety.

Future trends in material handling
The future of material handling in cement plants will be shaped by automation, digitalisation and sustainability considerations. Emerging technologies such as AI-driven logistics optimisation, autonomous mobile equipment and digital twins are expected to further improve plant efficiency and operational visibility. Digital twin models allow engineers to simulate material flow patterns, optimise stockyard operations and predict equipment performance under different operating conditions. According to the International Energy Agency Digitalisation and Energy Report, 2024, the adoption of advanced digital technologies could improve industrial energy efficiency by up to 20 per cent in heavy industries such as cement manufacturing. As cement plants expand capacity and adopt low-carbon technologies, intelligent material handling systems will play a critical role in maintaining productivity and reducing environmental impact.

Conclusion
Material handling systems have evolved from basic transport infrastructure into strategic operational systems that directly influence plant efficiency, reliability and sustainability. From quarry transport and automated stockyards to digital dispatch platforms and advanced conveying technologies, modern material handling solutions enable cement plants to manage large production volumes while maintaining process stability.
As India’s cement industry continues to expand to meet infrastructure and urban development demands, investments in advanced material handling technologies will become increasingly important. By integrating automation, digital monitoring and energy-efficient systems, cement manufacturers can improve operational performance while supporting the industry’s long-term sustainability and decarbonisation goals.