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Changing normal concrete into durable concrete for tunnelling application

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In this second part of the two-part series paper, the author EugenKleen of Mc-Bauchemie Mueller GmbH and Co.KG looks at the materials required to change normal concrete to durable media resistant concrete for use in tunnelling application.The main materials, which can help change normal concrete to durable aggressive media resistant concrete, are:??New generation PCE based admixtures??Condensed silica fume or microsilica slurry or??Latest generation aluminosilicatePCE based admixturesMost of the new generation superplasticizers are from the Acrylic Polymer (AP) family. Polycarboxylate is a common term for the substances that are specifically used as Polyacrylate or Polycarboxylate ether (PCE). The PCE based Super Plasticizers are by far superior to the conventional once with respect to initial slumping as well as slump retention with time. The efficient working of these plasticizers is due to the new type of molecule designs. PCE based superplasticizers produce excellent properties when used with cementitious materials. The disadvantages associated with longer setting times of conventional superplasticizers is offset by PCE based super plasticizer and therefore its use in concrete can also attain high early strengths. The development of highly effective superplasticizers with long and consistent duration of action is therefore an important precondition for the production durable concrete, due to low water contents and high early strength requirements.Concrete additives based on PCE offer advantages like:Significant reduction of the water demand of the mix??Little loss of consistency??Short setting times??High early strengths??Low tendency to segregationThe advantages of these new generation polymers are very clear, not only in terms of performance but also in terms of the dosages used for similar conditions and this factor balances the disadvantages in economy, as new generation superplasticizers are relatively expensive per unit price.Condensed Silica Fume/Microsilica:The term ‘microsilica’ is adopted to characterise the silica fume, which is used for the production of concrete. Microsilica or Condensed Silica Fume (CSF) is a by-product resulting from reduction of high purity quartz with coal in the electric arc furnaces used in manufacture of silicon, ferrosilicon and other alloys of silicon.There are three main reasons for the incorporation of silica fume as an additive for HPC. Microsilica has a filter effect i.e. very fine particle distributed itself in the space between the materials in the concrete in a homogenous way to give rise to more dense concrete. Silica fume improves the strength of the transition zone between cement paste and aggregates. CSF is highly pozzolanic in combination with Portland cement.During cement hydration there is surplus of calcium hydroxide. The added condensed silica fume’s SiO2 reacts with surplus of calcium hydroxide, which are greater amounts of calcium silicate hydrate, which are denser and stronger than calcium hydroxide. The pozzolanic reaction and the filler-effect lead to a compaction of the cement paste and the conversion of CH crystals into CSH gel leads to homogenous paste. The phenomenon of dense packing in the interface zone of aggregates also contributes to increase the strength of the concrete on account of aggregates fully contributing their strength of concrete with silica fume is greater than those of the matrix, indicating the contribution of the aggregate of microsilica (50:50 with water) have all the benefits in transportation, dispensing methods, mixing times and dispersions to get the desired effect in durable concrete for tunnelling segments.New Generation Aluminosilicates:New generation aluminosilicates based on special nano-crystalizers have been developed. These new materials improve the properties that are crucial for the durability of high performance concrete. In addition to reducing chloride migration, an exceptional chemical and resistance to aggressive media of the concrete can be achieved with aluminosilicates. The concrete structure is simultaneously reinforced right down to nanoscale, density is improved and compressive and flexure strength as well as abrasion resistance of the high-performance concrete is increased. There is also a significant reduction of micro-crack formation, which makes it particularly suitable for the production of tunnelling concrete. Aluminosilicate reduce the proportion of portlandite by way of a pozzolanic reaction that changes it into the aluminosilicate crystals into calcium silicate hydrate. In addition to the unique resistance against acids a crystalline micro-reinforcement within the concrete structure is achieved. This reduces the risk of micro-crack formation, rendering concrete impermeable.Due to high homogeneity and reduced tackiness compared with microsilica based concrete, workability is improved significantly. In many instances this enables the production of high-performance concrete that can be pumped. In addition, a distinct improvement of the building structure’s aesthetics is gained due to the fair appearance of the concrete surface. Aluminosilicates perform over some of the disadvantages of microsilica:??Graded for dispersion in concrete??Graded particle size??Optimises mixing time within concrete??Good dispersion reduces unreacted material in the mix and increases passivation by C-S-H gel on aggregate surface??Material if agglomerated improve strength of the mix??Reduces risk of alkali silica reaction by agglomeration of aluminosilicate particles.All in all, the use of PCE admixtures and microsilica or aluminosilicate slurries in addition to the standard ingredients in concrete, plus excellent mix-design practices can facilitate the production of high performance concretes resistant to aggressive media, suitable for use in tunnelling applications.

Key difference between Microsilica and Aluminosilica


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false

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Microsilica

Aluminosilica

1

By-product of
ferrosilicium and silicium production, not specifically produced for concrete

1

Manufactured product. It
is only produced for use as concrete additive

2

Quantities are depending
on the metal industry and the economic development

2

Quantities are not
depending on other industries and are unlimited, therefore reliable
availability

3

Quality of the product
has a higher deviation because it is only a by-product

3

High quality standards
for end product because every step in production is controlled




























































































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Concrete

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

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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.

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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.

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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…

To read the full article Click Here

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JK Cement Commissions 3 MTPA Buxar Plant, Crosses 31 MTPA

Company becomes India’s fifth-largest grey cement producer

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JK Cement  has commissioned its new 3 MTPA grey cement plant in Buxar, Bihar, taking the company’s total installed capacity to 31.26 million tonnes per annum (MTPA) and moving it past the 30 MTPA milestone. With this addition, JK Cement now ranks among the top five grey cement manufacturers in India, strengthening its national presence.

Commenting on the development, Dr Raghavpat Singhania, Managing Director, JK Cement, said, “Crossing 31 MTPA is a significant turning point in JK Cement’s expansion and demonstrates the scale, resilience, and aspirations of our company. In addition to making a significant contribution to Bihar’s development vision, the commissioning of our Buxar plant represents a strategic step towards expanding our national footprint. We are committed to developing top-notch manufacturing capabilities that boost India’s infrastructure development and generate long-term benefits for local communities.”

Spread across 100 acres, the Buxar plant is located on the Patna–Buxar highway, enabling efficient distribution across Bihar and neighbouring regions. While JK Cement entered the Bihar market last year through supplies from its Prayagraj plant, the new facility will allow local manufacturing and deliveries within 24 hours across the state.

Mr Madhavkrishna Singhania, Joint Managing Director & CEO, JK Cement, said, “JK Cement is now among India’s top five producers of grey cement after the Buxar plant commissioning. Our capacity to serve Bihar locally, more effectively, and on a larger scale is strengthened by this facility. Although we had already entered the Bihar market last year using Prayagraj supplies, local manufacturing now enables us to be nearer to our clients and significantly raise service standards throughout the state. Buxar places us at the center of this chance to promote sustainable growth for both the company and the region in Bihar, a high-growth market with strong infrastructure momentum.”

The project has involved an investment of Rs 5 billion. Commercial production began on 29 January 2026, following construction commencement in March 2025. The company said the plant is expected to generate significant direct and indirect employment and support ancillary industrial development in the region.

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