Concrete

Concrete Making Materials

Published

8 years ago

April 30, 2018

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Cement is never used as cement alone but is always converted to a value-added product in practice. Therefore application of cement becomes extremely important. The cement producers have a dedicated department that looks into the applications of product. Now onwards, we shall try and cover it through a series of articles in a structured way.
Construction aggregate, or "aggregate", is a broad category of coarse to medium grained particulate material used in construction that includes sand, gravel, crushed stone, slag, and recycled concrete and geosynthetic aggregates. Aggregates are the most mined materials in the world.
Cement concrete is a cement and water paste in which aggregate particles are embedded. Aggregate usually occupies approximately 60 to 75 per cent of the volume of concrete. Besides reducing volume changes due to drying shrinkage of the cement-water paste, aggregate is inexpensive filler that reduces the cost of the concrete. Aggregate properties significantly affect the workability of plastic (concrete in the wet stage) concrete and the durability, strength, thermal properties, and density of hardened concrete. Types of rocks
Aggregates are generally sourced from natural materials or from industrial by products. Natural aggregates come from rock, of which there are three broad geological classifications. Igneous rock: These rocks are primarily crystalline and are formed by the cooling of molten rock material beneath the earth’s crust (magma).Sedimentary rocks: These rocks are formed from deposited insoluble material (e.g., the remains of existing rock deposited on the bottom of an ocean or lake). This material is transformed to rock by heat and pressure. Sedimentary rocks are layered in appearance and are further classified based on their predominant mineral as calcareous (limestone, chalk, etc.), siliceous (chert, sandstone, etc.) or argillaceous (shale, etc.).Metamorphic rock: These are igneous or sedimentary rocks that have been subjected to heat and/or pressure great enough to change their mineral structure so as to be different from the original rock.
Natural sands and gravels are the product of weathering and the action of wind or water, while stone sands and crushed stone are produced by crushing natural stone. Screening and washing may be used to process aggregates from either of these categories. Aggregates may be produced from igneous, sedimentary, or metamorphic rocks, but the presence or absence of any geological type does not, by itself, make an aggregate suitable or unsuitable for use in concrete. The acceptance of an aggregate for use in concrete on a particular job should be based upon specific information obtained from tests used to measure the aggregate quality, or upon its service record, or both. Synthetic aggregates may be either by products of an industrial process, such as blast-furnace slag, or products of processes developed to manufacture aggregates with special properties, such as expanded clay, shale or slate that are used for lightweight aggregates. Some lightweight aggregates such as pumice or scoria also occur naturally. Other classifications of aggregates may be based upon bulk density and particle shape, but these, as well as the ones previously discussed, serve mainly as aids in describing an aggregate. To understand the role played by aggregate in the performance of concrete, it is necessary to define specific aggregate properties and show their effect on concrete properties.Aggregates generally divided into two groups: Fine and Coarse aggregates.
Fine aggregates or natural or manufactured of particle size ranging from 10 mm to 0.075 mm. Coarse aggregates size ranging from 10 mm to 80 mm. The most commonly used maximum size of aggregate is 20 or 25 mm.Fine & Coarse aggregates
– IS-383 – 2016 Specification for concrete
– IS-2386 Part – I to VIII – Method of testWhy use aggregates?
We use aggregates mainly to reduce the cost of the concrete. Roughly aggregates would cost between 12 to 25 per cent of the cement price. Use of aggregate reduces thermal cracking. About 100 kg of OPC produces about 12o C temperature rise. Aggregates can reduce shrinkage, 10 percent of reduction in aggregate volume can double the shrinkage of concrete. High aggregate to cement ratio is desirable as it mainly influences cement content in concrete. Effect of aggregate size: Larger the (maximum) size; increases strength, decrease total surface area of aggregate that decreases required cement content. Improves rut resistance but increases problem with segregation of particles. Smaller maximum size can reduce segregation, reduces road noise, decreases tyre wear specially while transporting of ready mixed concrete. Why to specify sizes?
The foremost reason for specifying the size of aggregates is to control the cost of concrete, have a homogenous mix with higher bulk density, effectively use the water content and control the consumption of cement and other cementious
materials. By playing with the size of aggregates one can modify workability, pumpability, porosity and shrinkage of concrete.
Fine aggregates are nothing but the sand used in concrete. The size is down 4.75 mm to 0.075 mm and the content is usually 35 per cent to 45 per cent by mass or volume of total aggregate. Grading of aggregates: Grading is nothing but the particle-size distribution of an aggregate as determined by a sieve analysis using wire mesh sieves with square openings. As per IS:2386 (Part-1) for fine aggregate, 6 standard sieves with openings from 150 ?m to 4.75 mm. (150 ?m, 300 ?m, 600 ?m, 1.18 mm, 2.36 mm, 4.75mm) are used. For coarse aggregates , 5 sieves with openings from 4.75 mm to 80 mm. (4.75 mm, 10 mm, 12.5 mm, 20 mm, 40 mm and may be onwards). ?m is microns and 1 micron (?m) is 0.001 mm.
Grain size distribution for concrete mixes should be such that it will provide a dense strong mixture. Ensure that the voids between the larger particles are filled with medium particles. The remaining voids are filled with still smaller particles until the smallest voids are filled with a small amount of fines.
Generally in the city of Mumbai and around three type of aggregates are used which are termed as CA I( coarse aggregate),CA II and FA fine aggregates. For coarse aggregates the sizes vary from 20-25mm for CAII and 10-12 mm for CAI, the remaining third is Fine aggregate or Sand. The proportion of sand in concrete being 35 to 45 per cent, availability and price of sand has a direct impact on the production of concrete.
Fineness Modulus (FM) is a result of aggregate sieve analysis is expressed by a number called Fineness Modulus. It is obtained by adding the sum of the cumulative percentages by mass of a sample aggregate retained on each of a specified series of sieves and dividing the sum by 100. This measurement is important while designing concrete mixes with given materials at site.
Sand or fine aggregates is further graded in three categories and the following limits may be taken as guidance:Fine sand : Fineness Modulus : 2.2 – 2.6Medium sand : F.M. : 2.6 – 2.9Coarse sand : F.M. : 2.9 – 3.2
Sand having a fineness modulus more than 3.2 will be unsuitable for making satisfactory concrete.Colour of aggregates: Normally the colour of aggregates depend on the source of rock from which it is derived. The colour of aggregates that we see in Karnataka, Maharashtra and in the Northen part of India is much different. However colour has hardly any influence on the properties of concrete. But in case of decorative concretes the colour needs to satisfy the designer’s requirements. Tests on Aggregates: Fine aggregates
These are summarised as Grading, Silt & Clay content, Specific Gravity, Water absorption & moisture content, Soundness, Alkali Aggregate Reactivity, Organic Impurities and Soft Particles, Bulkage. We shall cover some of the important ones.
Impurities in fine aggregate and its effect: Clay particles, Shale, Mica, Weathered agate, Organic impurities-humus, sugar etc. These impurities lead to High water absorption, Low strength, High shrinkage, Retardation. (Slow strength gain for concrete).
Estimation of stilt content and organic impurities is very simple and can be easily carried out at site laboratory. It is recommended that every site laboratory must carry out these tests to ascertain the suitability of fine aggregates. Tests on Coarse aggregates:
– Specific gravity
– Dry Loose Bulk Density/Dry Relative Bulk Density
– Absorption & Surface moisture
– Shape
– Soundness
(Test methods – IS 2386 Part I to VIII)Tests on Coarse aggregates:
– Aggregate Crushing Value
– Aggregate Impact Value
– Aggregate Abrasion Value
– Alkali Aggregate Reactivity
(Test methods – IS 2386 Part I to VIII)Mechanical properties
Aggregate Crushing Value: Not more than 45 percent for other than wearing, surface and 30 percent for wearing surface.
Aggregate Impact Value: Not more than 45percent for other than wearing, surface and 30 percent for wearing surface.
Aggregate Abrasion Value: Not more than 50 per cent for other than wearing surface and 30 percent for wearing surface.
Aggregate Elongation & Flakiness: Not more than 40 percent (combined)
Soundness: (Loss after 5 cycles)
For fine aggregate: maximum 10 percent with sodium sulphate and 15 percent with magnesium sulphate.
For Coarse aggregate: maximum 12 percent with sodium sulphate and 18 percent with magnesium sulphate.
We thankfully acknowledge for making the articles available to us originally written by Suhas Dhuri and S Krishnan of e cube consultants, Thane and Prof. Gaurav H Tondan published on Linked in.Compilation by Vikas Damle Ex. Editor of ICR.

Concrete

FORNNAX Appoints Dieter Jerschl as Sales Partner for Central Europe

Published

2 weeks ago

February 5, 2026

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FORNNAX TECHNOLOGY has appointed industry veteran Dieter Jerschl as its new sales partner in Germany to strengthen its presence across Central Europe. The partnership aims to accelerate the adoption of FORNNAX’s high-capacity, sustainable recycling solutions while building long-term regional capabilities.

FORNNAX TECHNOLOGY, one of the leading advanced recycling equipment manufacturers, has announced the appointment of a new sales partner in Germany as part of its strategic expansion into Central Europe. The company has entered into a collaborative agreement with Mr. Dieter Jerschl, a seasoned industry professional with over 20 years of experience in the shredding and recycling sector, to represent and promote FORNNAX’s solutions across key European markets.

Mr. Jerschl brings extensive expertise from his work with renowned companies such as BHS, Eldan, Vecoplan, and others. Over the course of his career, he has successfully led the deployment of both single machines and complete turnkey installations for a wide range of applications, including tyre recycling, cable recycling, municipal solid waste, e-waste, and industrial waste processing.

Speaking about the partnership, Mr. Jerschl said,
“I’ve known FORNNAX for over a decade and have followed their growth closely. What attracted me to this collaboration is their state-of-the-art & high-capacity technology, it is powerful, sustainable, and economically viable. There is great potential to introduce FORNNAX’s innovative systems to more markets across Europe, and I am excited to be part of that journey.”

The partnership will primarily focus on Central Europe, including Germany, Austria, and neighbouring countries, with the flexibility to extend the geographical scope based on project requirements and mutual agreement. The collaboration is structured to evolve over time, with performance-driven expansion and ongoing strategic discussions with FORNNAX’s management. The immediate priority is to build a strong project pipeline and enhance FORNNAX’s brand presence across the region.

FORNNAX’s portfolio of high-performance shredding and pre-processing solutions is well aligned with Europe’s growing demand for sustainable and efficient waste treatment technologies. By partnering with Mr. Jerschl—who brings deep market insight and established industry relationships—FORNNAX aims to accelerate adoption of its solutions and participate in upcoming recycling projects across the region.

As part of the partnership, Mr. Jerschl will also deliver value-added services, including equipment installation, maintenance, and spare parts support through a dedicated technical team. This local service capability is expected to ensure faster project execution, minimise downtime, and enhance overall customer experience.

Commenting on the long-term vision, Mr. Jerschl added,
“We are committed to increasing market awareness and establishing new reference projects across the region. My goal is not only to generate business but to lay the foundation for long-term growth. Ideally, we aim to establish a dedicated FORNNAX legal entity or operational site in Germany over the next five to ten years.”

For FORNNAX, this partnership aligns closely with its global strategy of expanding into key markets through strong regional representation. The company believes that local partnerships are critical for navigating complex market dynamics and delivering solutions tailored to region-specific waste management challenges.

“We see tremendous potential in the Central European market,” said Mr. Jignesh Kundaria, Director and CEO of FORNNAX.
“Partnering with someone as experienced and well-established as Mr. Jerschl gives us a strong foothold and allows us to better serve our customers. This marks a major milestone in our efforts to promote reliable, efficient and future-ready recycling solutions globally,” he added.

This collaboration further strengthens FORNNAX’s commitment to environmental stewardship, innovation, and sustainable waste management, supporting the transition toward a greener and more circular future.

Concrete

Budget 2026–27 infra thrust and CCUS outlay to lift cement sector outlook

Published

2 weeks ago

February 2, 2026

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Higher capex, city-led growth and CCUS funding improve demand visibility and decarbonisation prospects for cement

Mumbai

Cement manufacturers have welcomed the Union Budget 2026–27’s strong infrastructure thrust, with public capital expenditure increased to Rs 12.2 trillion, saying it reinforces infrastructure as the central engine of economic growth and strengthens medium-term prospects for the cement sector. In a statement, the Cement Manufacturers’ Association (CMA) has welcomed the Union budget 2026-27 for reinforcing the ambitions for the nation’s growth balancing the aspirations of the people through inclusivity inspired by the vision of Narendra Modi, Prime Minister of India, for a Viksit Bharat by 2047 and Atmanirbharta.

The budget underscores India’s steady economic trajectory over the past 12 years, marked by fiscal discipline, sustained growth and moderate inflation, and offers strong demand visibility for infrastructure linked sectors such as cement.

The Budget’s strong infrastructure push, with public capital expenditure rising from Rs 11.2 trillion in fiscal year 2025–26 to Rs 12.2 trillion in fiscal year 2026–27, recognises infrastructure as the primary anchor for economic growth creating positive prospects for the Indian cement industry and improving long term visibility for the cement sector. The emphasis on Tier 2 and Tier 3 cities with populations above 5 lakh and the creation of City Economic Regions (CERs) with an allocation of Rs 50 billion per CER over five years, should accelerate construction activity across housing, transport and urban services, supporting broad based cement consumption.

Logistics and connectivity measures announced in the budget are particularly significant for the cement industry. The announcement of new dedicated freight corridors, the operationalisation of 20 additional National Waterways over the next five years, the launch of the Coastal Cargo Promotion Scheme to raise the modal share of waterways and coastal shipping from 6 per cent to 12 per cent by 2047, and the development of ship repair ecosystems should enhance multimodal freight efficiency, reduce logistics costs and improve the sector’s carbon footprint. The announcement of seven high speed rail corridors as growth corridors can be expected to further stimulate regional development and construction demand.

Commenting on the budget, Parth Jindal, President, Cement Manufacturers’ Association (CMA), said, “As India advances towards a Viksit Bharat, the three kartavya articulated in the Union Budget provide a clear context for the Nation’s growth and aspirations, combining economic momentum with capacity building and inclusive progress. The Cement Manufacturers’ Association (CMA) appreciates the Union Budget 2026-27 for the continued emphasis on manufacturing competitiveness, urban development and infrastructure modernisation, supported by over 350 reforms spanning GST simplification, labour codes, quality control rationalisation and coordinated deregulation with States. These reforms, alongside the Budget’s focus on Youth Power and domestic manufacturing capacity under Atmanirbharta, stand to strengthen the investment environment for capital intensive sectors such as Cement. The Union Budget 2026-27 reflects the Government’s focus on infrastructure led development emerging as a structural pillar of India’s growth strategy.”

He added, “The Rs 200 billion CCUS outlay for various sectors, including Cement, fundamentally alters the decarbonisation landscape for India’s emissions intensive industries. CCUS is a significant enabler for large scale decarbonisation of industries such as Cement and this intervention directly addresses the technology and cost requirements of the Cement sector in context. The Cement Industry, fully aligned with the Government of India’s Net Zero commitment by 2070, views this support as critical to enabling the adoption and scale up of CCUS technologies while continuing to meet the Country’s long term infrastructure needs.”

Dr Raghavpat Singhania, Vice President, CMA, said, “The government’s sustained infrastructure push supports employment, regional development and stronger local supply chains. Cement manufacturing clusters act as economic anchors across regions, generating livelihoods in construction, logistics and allied sectors. The budget’s focus on inclusive growth, execution and system level enablers creates a supportive environment for responsible and efficient expansion offering opportunities for economic growth and lending momentum to the cement sector. The increase in public capex to Rs 12.2 trillion, the focus on Tier 2 and Tier 3 cities, and the creation of City Economic Regions stand to strengthen the growth of the cement sector. We welcome the budget’s emphasis on tourism, cultural and social infrastructure, which should broaden construction activity across regions. Investments in tourism facilities, heritage and Buddhist circuits, regional connectivity in Purvodaya and North Eastern States, and the strengthening of emergency and trauma care infrastructure in district hospitals reinforce the cement sector’s role in enabling inclusive growth.”

CMA also noted the Government’s continued commitment to fiscal discipline, with the fiscal deficit estimated at 4.3 per cent of GDP in FY27, reinforcing macroeconomic stability and investor confidence.

Concrete

Steel: Shielded or Strengthened?

CW explores the impact of pro-steel policies on construction and infrastructure and identifies gaps that need to be addressed.

Published

2 weeks ago

January 31, 2026

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Going forward, domestic steel mills are targeting capacity expansion
of nearly 40 per cent through till FY31, adding 80-85 mt, translating
into an investment pipeline of $ 45-50 billion. So, Jhunjhunwala points
out that continuing the safeguard duty will be vital to prevent a surge
in imports and protect domestic prices from external shocks. While in
FY26, the industry operating profit per tonne is expected to hold at
around $ 108, similar to last year, the industry’s earnings must
meaningfully improve from hereon to sustain large-scale investments.
Else, domestic mills could experience a significant spike in industry
leverage levels over the medium term, increasing their vulnerability to
external macroeconomic shocks.(~$ 60/tonne) over the past one month,
compressing the import parity discount to ~$ 23-25/tonne from previous
highs of ~$ 70-90/tonne, adds Jhunjhunwala. With this, he says, “the
industry can expect high resistance to further steel price increases.”

Domestic HRC prices have increased by ~Rs 5,000/tonne
“Aggressive
capacity additions (~15 mt commissioned in FY25, with 5 mt more by
FY26) have created a supply overhang, temporarily outpacing demand
growth of ~11-12 mt,” he says…

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