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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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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

Akhoya Gets New 2.2 Km Road Link Under SASCI

Two cement concrete roads opened at Rs 29.1 million (mn) cost

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Two cement concrete pavement roads covering a total stretch of 2.2 km in Akhoya village were inaugurated on 27th June 2026 by MLA Nuklutoshi Longkumer, who attended as the special guest. The project comprises the one km L Pangersowa Road and the one point two km Longchara Junction to RC Chiten Jamir Memorial Government High School road. A formal programme followed the inauguration at the school auditorium.

A technical report was presented by Er Waloniba of the Urban Engineering Wing-III, Kohima, which stated the project was sanctioned in March 2026 under the Special Assistance to States for Capital Investment scheme for 2025-26 at a sanctioned cost of Rs 29.1 million (mn). The work order was issued to M/s Ensign Construction on thirtieth April 2026 with a stipulated completion period of 12 months. Work commenced on fourth May 2026 and was completed on sixth June 2026, with the contractor and team finishing the tasks in around two months. The project included a single-lane cement concrete pavement with side drains, two slab culverts and breast walls at required locations.

Longkumer acknowledged the Chief Minister, the advisor for urban development, contractors and other stakeholders for the allocation and support, and he commended the contractor for early completion. He noted that cooperation from landowners and the community had been important in resolving land related issues that can otherwise delay developmental works. He emphasised that planned developmental activities carried out with collective effort would enable more projects to be implemented successfully.

The headmaster of RC Chiten Jamir Memorial Government High School, I Chubasenba Longkumer, outlined the school background, noting it was established in 1962, was earlier known as Government High School Changtongya and was renamed in 2014. Local representatives said the improved approach roads would ease access for students, staff, patients and the general public and fulfil a long standing aspiration of residents. A dedicatory prayer was offered by the pastor and the programme concluded with a ribbon cutting attended by village council and town council representatives.

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Green Construction Through Cement Innovation

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Indian Cement Review (ICR) and Fuller Technologies brought industry, policy and technology leaders together to discuss how cement innovation can drive green construction at scale, writes Rakesh Rao.

India is building at a pace few countries can match. Highways, airports, housing, logistics parks, industrial corridors and urban infrastructure are reshaping the country’s economic geography. But beneath this growth story lies a difficult question: can India continue to build at scale without locking itself into a high-carbon future?

That question formed the core of an online panel discussion titled “Driving Green Construction Through Cement Innovation”, organised by Indian Cement Review (ICR) in association with Fuller Technologies as the Presenting Partner on June 25, 2026. The webinar brought together experts from cement technology, R&D, global industry platforms, building performance policy and international development cooperation to examine how low-carbon cement and material innovation can accelerate India’s green construction transition.

The discussion came at a crucial time. India has committed to achieving net-zero emissions by 2070 and reducing the carbon intensity of its economy by 45 per cent by 2030. At the same time, the country’s construction sector is expanding rapidly, driven by urbanisation, infrastructure development, housing demand and industrial growth. Cement, as one of the most widely used construction materials, sits at the heart of this transition. It is indispensable to development, but also central to the challenge of reducing embodied carbon in buildings and infrastructure.

Moderated by Nitika Krishan, Senior Urban Infrastructure and Sustainable Policy Consultant, the panel featured:

  • Kiranmai Sanagavarapu, Director, Low Carbon Solutions, Fuller Technologies;
  • Dr Hemantkumar Aiyer, VP and Head R&D, Nuvoco Vistas Corp Ltd;
  • Devika Wattal, Innovation Lead, Global Cement and Concrete Association (GCCA);
  • Dr Sunita Purushottam, MD, GBPN India (Global Buildings Performance Network); and
  • Vaibhav Rathi, Senior Technical Advisor, GIZ (the German Agency for International Cooperation)

Setting the tone for the discussion, Nitika Krishan underlined the scale of the challenge before the sector. “The question before us is no longer whether we build, but how we build sustainably,” she said. She pointed out that construction accounts for nearly 40 per cent of global energy-related carbon emissions when both operational and embodied carbon are considered. Cement production, she added, remains one of the hardest industrial processes to decarbonise.

For India, this is not merely an environmental issue. It is a development issue, a competitiveness issue and increasingly, a market issue. As one of the world’s largest cement producers and among the fastest-growing construction markets, India’s material choices will influence the carbon trajectory of its built environment for decades. As Krishan observed, sustainability solutions in economies such as India must not remain limited to laboratory success. They must be scalable, commercially viable and practical at national level.

The innovation gap: From technology to market

Experts believe that there is a need to bridge the innovation gaps for making decarbonisation in cement and concrete scalable. Devika Wattal of GCCA, explained, “The starting point must be the core cement manufacturing process itself. The first and foremost is the heart of our process, the heart of cement manufacturing. How do we reduce clinker? That is always a topic where industry is working very intrinsically.”

Clinker reduction remains one of the most important pathways for lowering emissions in cement. Since clinker production is energy-intensive and chemically emits carbon dioxide, reducing the clinker factor through supplementary cementitious materials (SCMs), blended cements and new chemistries can have a significant impact. Wattal also noted that carbon capture, utilisation and storage (CCUS) will have a role, though it may not be the first lever for all markets.

However, she stressed that innovation cannot stop at technology development. A solution that works in the lab must also be adaptable to industry, scalable in production and acceptable in construction practice. “It is important for that innovation to be adaptable, to be scalable, and so that it can be executed in real time,” she said.

Wattal also called for stronger enabling systems around innovation. These include performance-based standards, product-level embodied carbon databases and clearer frameworks for evaluating green materials. Without these, low-carbon cement products may struggle to compete with conventional materials in procurement and design.

R&D must balance carbon, cost and performance

Bringing in the R&D perspective into the discussion, Dr Hemantkumar Aiyer of Nuvoco Vistas emphasised that low-carbon cement development cannot be treated as a single-variable exercise. Cement must perform in real construction conditions. It must deliver strength, durability, consistency and cost competitiveness, while also reducing carbon.

“The root of understanding and balancing all these aspects lies in materials, and knowing the materials,” he said.

According to Dr Aiyer, R&D teams must understand the variability of raw materials such as fly ash, slag and clinker. Different sources produce different material behaviours. This makes mix optimisation, material characterisation and processing-property relationships critical. When performance is affected, cement manufacturers must understand how strength enhancers, admixtures and other performance chemicals interact with the material system.

He also linked material science with process efficiency. Clinkerisation takes place at extremely high temperatures, around 1,400 to 1,450 degrees Celsius. Any improvement in raw mix design, process control or energy optimisation can, therefore, help reduce emissions and cost. Dr Aiyer pointed to artificial intelligence-based optimisation, Cement 4.0 tools and advanced software as important enablers for real-time process and material control.

“The more you understand the materials, the more you can control it,” he said.

LC3: The promise is proven, the sequencing is not

Limestone calcined clay cement, commonly referred to as LC3, has attracted global attention because it can reduce clinker content significantly by using calcined clay and limestone while maintaining performance in many applications. Kiranmai Sanagavarapu of Fuller Technologies said the technology itself has already moved beyond proof of concept. Fuller Technologies has worked with calcined clay technology for nearly two decades and has seen plants running in France and Ghana. These plants, she said, are meeting local and national specifications, while the economics are beginning to make sense.

“The calciner is performing, the economics is stacking up, it is making business sense to produce,” she said.

But if the technology is viable, why has adoption not scaled faster? For Sanagavarapu, the answer lies in project sequencing. Too often, clay characterisation happens after equipment is specified. This, she warned, is a backward approach because calciner design depends on clay mineralogy, kaolinite content, iron levels, reactivity, moisture and other variables.

“If you don’t know what your deposit looks like before you commit for the equipment, you are, in a way, going blind into designing,” she said.

She also identified permitting and plant integration as major bottlenecks. Environmental clearances, mining permissions and local regulatory approvals must begin early. Similarly, calcined clay must be integrated into existing grinding, blending and logistics systems from the design stage, not treated as an afterthought during commissioning.

India already has IS 18189:2023 standard for LC3, but Sanagavarapu pointed out that the standard is not yet visible enough in procurement documents. “The gap between what is technically being permitted and what the procurement is asking is the single biggest bottleneck,” she said.

In her view, successful scale-up depends on getting the sequence right: clay characterisation first, permitting in parallel, standards aligned with construction, and integration built into plant design.

India’s LC3 journey: Progress, but demand remains thin

Providing details of India’s LC3 commercialisation experience, Vaibhav Rathi of GIZ noted that JK Cement carried out the first commercial production of LC3 at its Rajasthan plant, followed by JK Lakshmi Cement three months later. These initiatives were supported by the International Climate Initiative of the Government of Germany, with IIT Delhi contributing deep institutional knowledge on LC3 research and BIS certification.

Rathi said India’s early experience has produced clear lessons. One of the biggest was the need to build capacity among regulators. While BIS certification existed, State Pollution Control Boards were unfamiliar with the technology and unsure about the approval pathway.

“The capacity building is not just needed amongst the producer and the users of the cement, but also the regulators who are working with this technology for the first time,” he said.

He also highlighted the need for better information on China clay deposits. Since China clay is currently classified as a minor mineral, centralised data on availability, quality and location is limited. If cement manufacturers are to adopt LC3 at scale, stronger mineral intelligence will be important.

The third issue is demand. LC3 has already been used in projects such as Palava City in Mumbai and Noida International Airport, but these remain limited examples. “It is in a chicken and egg situation,” Rathi said. “Cement companies are saying we need more demand, and users are saying there is not enough cement available.”

Public procurement, he suggested, could help break this cycle. If agencies such as CPWD and other public bodies begin testing, accepting and specifying LC3, it could create the market confidence needed for cement companies to invest in production and storage.

Building codes must catch up with innovation

Dr Sunita Purushottam of GBPN India argued that material choices will determine built environment emissions over the long term, but India’s current policy signals remain fragmented. Although LC3 has received BIS recognition, she pointed out that building codes, municipal bylaws, schedules of rates and sustainability codes do not yet provide uniform guidance on low-carbon cement.

“The current cement regulations are largely prescriptive and favouring traditional materials,” she said. This limits the ability of alternative materials to compete on performance, durability and emissions.

Dr Purushottam also raised the issue of taxation. Cement, including LC3, currently falls under the same GST bracket as conventional cement. A differentiated tax structure, she argued, could help accelerate market adoption. “In order for the market to demand LC3, that differentiation in the GST could go a long way,” she said.

She noted that green building certifications such as IGBC and GRIHA are already creating demand for low-carbon materials by assigning points for embodied carbon and sustainable material use. However, she said large-scale adoption will require regulatory mandates, particularly through building codes and state-level notifications.

She also cautioned that low-carbon cement alone does not solve the entire building performance problem. A material may reduce embodied carbon, but the operational carbon of a building depends on thermal performance, design, insulation and energy use. “The energy part has two elements,” she said. “One is the embodied carbon of the material itself, and the other is the operational carbon.”

Collaboration is the bridge between invention and impact

Wattal said GCCA sees innovation as a strategic priority and works through platforms that connect industry with academia and start-ups. “There is no way we will decarbonise our sector without innovation,” she said.

However, she stressed that research must be connected to actual industry challenges. Innovations developed in isolation may fail when they encounter real-world barriers such as raw material variability, plant integration, cost, standards and finance. Start-ups, too, need industry mentorship and scale-up pathways.

Wattal also flagged the importance of finance. Even strong technologies may struggle to attract investment if there is no common understanding of bankability. “We have always put projects into, is this a bankable project? But the definition of a bankable project has never been defined,” she said.

For India, she saw strong potential in its academic and start-up ecosystem, but said the challenge lies in alignment and prioritisation. The country has the research base, industrial capacity and market size. What it now needs is a coordinated route from innovation to deployment.

There is a practical concern for cement manufacturers: how can existing plants be adapted for lower emissions without compromising reliability or commercial viability?

Kiranmai Sanagavarapu addressed, “The reliability risk in calcined clay retrofit is definitely real, but it is almost always self-inflicted. The risk arises when a new process is added to an existing circuit without properly redesigning grinding and blending configurations.”

Existing cement plants, she explained, can take two broad routes. The first is external sourcing of calcined clay combined with mill optimisation. This requires lower capital investment and can potentially move in 12 to 18 months if other conditions are in place. It may reduce emissions by around 20 to 30 per cent. The second route is integrated calcination on site, which requires higher capital expenditure and longer lead times, but provides greater control over quality, supply and emissions reduction potential.

For Sanagavarapu, the principle is simple: low-carbon retrofits must be designed with intent. “Design it with an intent properly from the start. Start in the market conditions where the economics are already working,” she said.

Circularity: The overlooked advantage

According to Vaibhav Rathi, fly ash and slag are already well established in cement and construction (C&D), but construction and demolition waste remains underutilised. “C&D waste is a growing business opportunity which not many have taken up,” he said. India’s continuous construction and demolition activity creates huge volumes of waste, much of which contributes to air pollution, land degradation and material inefficiency. With the right processing and standards, this waste can be converted into useful construction products.

Rathi also pointed out that LC3 has a circular economy dimension that is often overlooked. It can use low-grade kaolin-rich clay left behind after high-grade clay is extracted for other applications. “LC3 is not only a low-carbon solution, but also a circular economy solution,” he said.

At the same time, he cautioned that LC3 in India is not yet cheap because it has not reached scale. Site-specific techno-commercial feasibility studies, supported jointly by development agencies and industry, could help companies assess whether LC3 production makes technical and financial sense at a given location.

Dr Purushottam added that India must address both low-carbon cement and construction waste together. “Both low-carbon cement and C&D waste go hand in hand. India does not have an option but to work on both,” she said.

Dr Aiyer called for policy shifts from both government and industry, including preferential purchasing of sustainable materials, minimum supplementary cementitious material requirements in public and public-private projects, and faster regulatory implementation. “If we can fast-track the regulatory standards and their implementation on the ground, that is the way to go,” he said.

From green ambition to green construction

Cement innovation is no longer only about chemistry. It is about systems. Low-carbon cement will scale only when technology, standards, procurement, finance, regulation, education and construction practice move together.

LC3 and other low-carbon technologies have shown promise. India has early commercial examples, strong research capability and growing market interest. But mainstream adoption will depend on whether demand can be created, regulators can be capacitated, standards can be embedded in procurement, and manufacturers can see a clear business case.

For a country building at India’s scale, the opportunity is enormous. Cement will continue to be central to infrastructure and urban development. The challenge now is to ensure that the cement used in India’s growth story carries a lower carbon burden.

  • Rakesh Rao

Participate in Cement Expo 2026 and discover how next-gen infrastructure can be built with innovations in cement.

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Concrete

JK Cement Declared Preferred Bidder For Gilund Limestone Block

Shares Edge Higher As Company Wins Rajasthan Block

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JK Cement gained after being declared preferred bidder for the Gilund Limestone Block in Chittorgarh, Rajasthan, a lease area of 370.96 hectares. The firm saw its shares trade at Rs. 5550.05, up by 28.45 points or 0.52 per cent from the previous close of Rs. 5521.60 on the BSE. The scrip opened at Rs. 5569.15 and touched a high of Rs. 5625.00 and a low of Rs. 5531.00.

The stock recorded turnover of 1742 shares on the counter and the BSE group A stock with face value Rs. 10 has a 52 week high of Rs. 7565.00 on 20-Aug-2025 and a 52 week low of Rs. 4670.05 on 12-Jun-2026. Last one week high and low stood at Rs. 5625.00 and Rs. 5329.00 respectively. The promoters holding in the company stood at 45.66 per cent, while institutions and non-institutions held 40.61 per cent and 13.73 per cent respectively.

The e-auction conducted by the Government of Rajasthan resulted in the company being declared preferred bidder for the mining lease, and the allocation will enable the company to plan phased development of the deposit, subject to regulatory approvals. The Gilund block spans 370.96 hectares and its allocation is intended to support raw material security for the company’s cement operations in the region. The designation follows the government auction process and will allow the company to plan development and integration of the deposit into its supply chain.

The current market capitalisation stands at Rs. 430.38 billion (bn), reflecting market response to the mining news and prevailing valuation levels for the sector. Investors and analysts will watch for formal allotment and related disclosures that can clarify timelines, capital expenditure and expected production profiles. The report is intended for informational purposes and does not constitute investment advice, and market participants are advised to consult advisers before making decisions.

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