Concrete

Making self consolidating concrete using building demolished waste

Published

13 years ago

November 30, 2012

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Preservation of the environment and conservation of the rapidly diminishing natural resources is the essence of sustainable development. Recycling of concrete from the Building Demolished Waste(BDW) to produce aggregates suitable for structural and non-structural applications is fast emerging as a commercially viable and technically feasible operation.Self-Compacting Concrete (SCC) is considered as a concrete which can be placed and compacted under its self-weight with little or no vibration effort, and which is at the same time, cohesive enough to be handled without segregation or bleeding. It is used to facilitate and ensure proper filling and good structural performance of restricted areas and heavily reinforced structural members.The use of Recycled Concrete Aggregate (RCA) in construction works is a subject of high priority in building industry throughout the world and it is a good solution to the problem of an excess of waste material, provided that the desired final product quality is reached. This reduces the consumption of the natural resources as well as the consumption of the landfills required for waste concrete. The technology today has advanced so far that it is forcing us to think in terms of ‘sustainability’. Ductility of concrete is provided with fiber reinforced cementitious composites, because fibers bridge crack surfaces and delay the onset of the extension of localised crack.Research significanceAn attempt has been made in the present investigation to develop a standard grade Self Compacting Concrete without and with polypropylene and glass fibers and without and with recycled aggregate. The present work provides very useful information for the practical use of fibrous self compacting concretes in the field, employing recycled aggregate form Building Demolished Waste (BDW).Properties of SCC in fresh stateA concrete mix is called Self Compacting Concrete if it fulfills the requirement of filling ability, passing ability and resistance to segregation. The filling ability is the ability of the SCC to flow into all spaces within the formwork under its own weight.Passing ability is required to guarantee a homogenous distribution of the components of SCC in the vicinity of obstacles. The resistance to segregation is the resistance of the com-ponents of SCC to migration or separation and remains uniform throughout the process of transport and placing. To satisfy these conditions EFNARC has formulated certain test procedures.IngredientsOrdinary Portland cement of 53 grade (compressive strength not less than 53 Mpa) was used in the study. The cement was selected as per IS-12269. Fine aggregate was standard river sand procured locally and was confirming to zone-II as per IS-2386. Crushed granite was used as coarse aggregate. The aggregate was passed through standard sieves of 16mm and retained on 4.75mm sieve. Recycled aggregate from building demolished waste was crushed and classified before use. For qualifying the utility of recycled aggregate in concrete, the important parameters like bulk density, voids ratio, specific gravity, water absorption, crushing and impact value, angularity and IAPST were determined based on IS Codal provisions. There properties were determined for different replacement of Recycled Concrete Aggregate (RCA) in Natural Aggregate (NA). The properties are shown in Table 1.Tests on FRSCRACThe slump flow equipment is currently used widely in concrete practice, and the method is very simple and straight forward. Thus the H-flow combined with T50 was selected as the first priority test method for estimating the filling ability of FRSCRAC. The V-funnel or Orimet tests are recommended as second priority alternatives to the T50 measurement. The passing ability of fresh SCC can be tested by U-box or J-ring. The basic properties of SCC without and with fiber and/or recycled aggregate are shown in Table 2. The fresh properties of SCC and FRSCC are suggestive of confirmation with the EFNARC Specifications.The source of fly ash used in the experiments was from a local coal fired thermal power station, where flyash is evolving out as a bye-product. The specific gravity was 2.05 with silicon dioxide content above 92 per cent. The fly ash was used as a partial replacement for cement. Conplast SP 337 superplasticizer and Viscosity Modifying Agent (VMA) were added in optimum dosages for improving the strength and workability properties of SCC. The Nansu mix design procedure is adopted to develop M40 Grade Concrete for different replacements of recycled aggregate in natural agg-regate and without or with fiber additions. The ingredients are shown in Table 3. The Glass Fiber (GF) is Cem-Fil Anti Crack and its specific gravity is 2.6 and the specific surface area is 105 m2 /kg. Poly Propylene Fiber (PF) with a diameter of 20-200 ?m, modulus of elasti-city 5-10 Gpa and tensile strength of over 500-750 mpa was used.Experimental programAn experimental program was designed to compare the strength properties of self- compacting concrete using recycled aggregate and without or with fiber addition. Cubes, cylinders and prisms of standard dimensions were cast and tested to determine the compressive strength, split tensile strength, flexural strength and modulus of elasticity of Fiber Reinforced Self- Compacting Concrete (FRSCC) using Recycled Aggregate (RA) from Building Demolished Waste (BDW).Casting and Testing of specimensThe influence of recycled aggregate and fiber on the behavior in compression, split tension and flexure is being investigated. 150×150 mm cubes for compressive strength, 150 mm diameter and 300 mm height cylinders for split tensile strength and 100x100x400 mm prism specimens for studying the modulus of rupture were employed. The program consisted of casting and testing a total number of 54 cubes, 54 cylinders and 54 prisms cast in 9 batches. Of these 54 cubes, 18 cubes corresponding to each Natural Aggregate (NA), 50 per cent Natural & Recycled (NARA) and 100per cent Recycled Aggregate (RA). Of these 18 cubes, six cubes correspond to each no fiber (WF), with PF and with GF additions. Similarly additional 54 cylinders (18 with NA, 18 with NARA, and 18 with RA) were cast for examining the stress-strain behavior of M40 grade for different fibers. The mix was designed as per modified Nansu method of mix design. All the specimens were demoulded after 24 hrs and kept in water for curing for 28days.The specimens were capped using plaster of paris to ensure plane-testing surface. Tinius Olsen Testing Machine (TOTM) of capacity 2000 KN was used for testing the specimens under standard load rate control. While testing, precautions were taken to ensure axial loading. For flexural strength standard three point loading was adopted. The modulus of elasticity of concrete was determined using compressometer setup and tested under TOTM.Discussion of test resultsThe results obtained from the detailed experimental program conducted on SCC without and with fiber are discussed. Table 4 shows the details of various mechanical properties viz., compressive strength, split strength and flexural strength for self-compacting concretes. The optimum fiber content was utilized through out the experimentation and this was based on initial strength and flow studies.Compressive strength of FRSCRAC

The mechanical properties of NA, NARA, and RA concrete cast without and with fiber additions are shown in Table 4.Addition of fibers has definitely increased the com-pressive strength, though marginally. The percentage increase in strength with fiber addition is plotted in Fig 5. It can be noted that the percentage increase is marginal. It is 1.90 per cent, 2.01 per cent in case of NA, 1.03 per cent, 1.62 per cent in 50 per cent Natural-Recycled Aggregate(NARA) and 0.94 per cent, 1.22 per cent in Recycled Aggregate(RA) with Polypropylene Fiber Reinforced Self-Compacting Concrete and Glass Fiber Reinforced Self-Compacting Concrete respectively. It can hence be concluded at this stage that fiber additions do not increase the compressive strength much.
Influence of fibers on split tensile strengthThe tensile strength of SCC is relatively much lower than its compressive strength because, it can be developed more quickly with crack propagation. Hence, it is important to improve the tensile strength of such a concrete. The variation of split tensile strength with fiber addi-tions is shown in Table 4. The increase is 14.19 per cent, 17.74 per cent in Natural Aggregate (NA), 9.97 per cent, 14.09 per cent in 50 per cent Natural-Recycled Aggregate (NARA) and 6.25 per cent, 11.72 per cent in Recycled Aggregate (RA) with GFRSCC and PFRSCC respectively (Fig 6). It can hence be inferred from the above that the fiber additions has a pronounced increase in the split tensile strength of self compacting concrete.Influence of fibers on flexural strength

Table 4 & Fig 7 show the details of the percentage increase in flexural strength for fiber additions. There is an increase in flexural strength of fibrous concretes as compared to no fiber concretes. The values are close to 0.7 as given by IS code for the relationship between flexural strength sqrt (fck) for normal concrete. The value of flexural strength to is more with polypropylene and glass fibrous concretes compared to no fiber concretes. From Fig 7, it is clear that there is an increase of 3.15 per cent, 13.32 per cent in Natural Aggregate(NA), 2.93 per cent, 9.57 per cent in 50 per cent Natural-Recycled (NARA) and 2.31 per cent, 8.96 per cent in Recycled Aggregate(RA) with GFRSCC and PFRSCC respectively. At this stage it may be concluded that the bending behaviour is greatly improved with glass fiber additions in self com-pacting concrete.Influence of fibers on modulus of elasticityThe brittle behavior of SCC is known. The fiber addition in such concretes modified the stress-strain behaviour of plain concrete. Using a compressometer setup and under compression the stress-strain values are evaluated and curves were drawn for the initial elastic portions. The Modulus of Elasticity (E) was calculated, following the specifications as laid by IS Code 516-1999. Table 4 shows the details of the values of modulus of elasticity for self-compacting concrete for Natural(NA), 50per cent Natural-Recycled (NARA) and Recycled Aggregate(RA) and without & with fiber respectively. It may be concluded that the addition of fiber in general increased the value of Modulus of Elasticity (E) of self-compacting recycled aggregate concrete. These values were close to 5000*vfck in case of no fiber concrete and higher in case of fibrous concretes.ConclusionsBased on experimental study on Fiber Reinforced Self Compacting Concrete (FRSCC) using recycled aggregate the following conclusions can be drawn.??From the properties of RCA it can be concluded that the coarse aggregate obtained from crushing BDW can be used for structural concrete works. This confirms the fact that RCA is in no way inferior to NA.??Self Compacting Concretes could be developed with recycled aggregate using high powder content, lesser quantity of coarse aggregate, high range super plasticizer and VMA to provide stability and fluidity to the concrete mixes.??There is a marginal increase in compressive strength, very good increase in the split tensile strength and a good increase in the flexural strength of FRSCRAC. The increase in split tensile and flexural strength is more in the case of glass fiber as compared to polypropylene fiber.??The relationship between compressive and split tensile strength and flexural and characteristic compressive strength for without and with fiber is suggested.??The fibrous specimens failed only by splitting of the fiber and there was no deboning of fibers noticed in any of the specimens.

Concrete

JSW Cement Begins Production At Nagaur Rajasthan Plant

Greenfield integrated cement plant begins operations in Rajasthan

Published

2 hours 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

2 hours 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.