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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
false
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

Cement Makers Reaffirm Commitment to Sustainable Growth

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World Environment Day spotlight on innovation and circularity

On World Environment Day, the Indian cement industry reiterated its commitment to supporting India’s climate ambitions through sustainable manufacturing, resource efficiency and the adoption of cleaner technologies.

The Cement Manufacturers’ Association (CMA) said the sector remains aligned with the Government of India’s Net Zero commitments and is accelerating efforts to reduce its environmental footprint while supporting the country’s infrastructure and development agenda.

Parth Jindal, President, CMA and Managing Director, JSW Cement, said the industry is increasingly adopting cleaner technologies, improving energy efficiency and expanding the use of alternative fuels and raw materials. He also highlighted the growing importance of circular economy practices, where industrial by-products and waste streams from one sector are utilised as resources in another.

“The Indian Cement Industry is aligned to the Government’s commitments on carbon mitigation and is accelerating the adoption of cleaner technologies, resource efficiency and circular economy practices while actively exploring the potential of Carbon Capture, Utilisation and Storage (CCUS) as a critical pathway for deep decarbonisation,” said Jindal.

He added that coprocessing industrial waste and by-products helps conserve natural resources, reduce disposal requirements and lower the environmental footprint across multiple sectors.

According to Jindal, sustainability is no longer limited to manufacturing processes but is increasingly influencing investment decisions, innovation strategies and long-term growth plans within the industry.

Echoing similar views, Dr Raghavpat Singhania, Vice President, CMA and Managing Director, JK Cement, said sustainable development extends beyond emissions reduction and must also focus on responsible resource utilisation and waste minimisation.

“Sustainability in the built environment cannot be measured by emissions alone. It is equally about how efficiently we use resources, how effectively we minimise waste and how responsibly we create the infrastructure that will serve future generations,” said Singhania.

He noted that the cement industry is advancing its sustainability agenda through greater resource efficiency, increased circularity, technological innovation and continuous improvements in manufacturing practices. As a key contributor to India’s infrastructure development, the sector has a critical role to play in balancing economic growth with environmental responsibility.

On the occasion of World Environment Day, industry leaders reaffirmed their commitment to supporting India’s climate goals while delivering the materials required for resilient, durable and sustainable infrastructure.

 

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Concrete

Building a Greener Future Together

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Environmental sustainability requires immediate action, not just long-term commitments and discussions. Recycling, circular economy practices, and technology-driven waste management can help industries reduce environmental impact while supporting sustainable growth.

Author: Jignesh Kundaria, Director and CEO, Fornnax Technology

World Environment Day serves as an important reminder that environmental sustainability can no longer remain confined to discussions, reports, or long-term commitments. The environmental challenges facing the world today demand immediate, measurable, and collective action. Across industries and communities, waste generation continues to outpace our ability to process it responsibly, placing increasing pressure on ecosystems, natural resources, public health, and the well-being of future generations.

One of the most significant shifts required today is a change in how society perceives waste. Rather than being viewed as a material to be discarded, waste must be recognised as a valuable resource that can contribute to both economic growth and environmental protection when managed through the right technologies and systems. This mindset forms the foundation of the circular economy model that countries across the world are increasingly adopting to reduce landfill dependence, recover valuable materials, and create more sustainable industrial ecosystems.

India has made meaningful progress in strengthening awareness around sustainability, recycling, and environmental responsibility over the past decade. Significant efforts are being made to formalise the recycling sector through improved infrastructure, technology adoption, policy implementation, and broader stakeholder participation. These developments are creating a stronger foundation for responsible waste management and resource recovery across the country.

However, achieving long-term environmental impact requires collaboration from all stakeholders. Industries, policymakers, technology providers, and communities must work together with greater accountability to strengthen recycling ecosystems, encourage responsible waste management practices, and create sustainable outcomes through consistent execution rather than temporary interventions.

As someone closely associated with the recycling industry, I firmly believe that technology will play a decisive role in addressing future environmental challenges. Advanced recycling systems have the potential to recover valuable resources, reduce pollution, minimise landfill burdens, and conserve energy, creating a more sustainable future for generations to come. This belief is deeply reflected in Fornnax’s motto, “Committed to Create a Green Future,” which embodies our commitment to building long-term environmental value through innovation and responsible action.

At the same time, technology alone cannot deliver meaningful change. Real progress requires intent, awareness, participation, and a shared sense of responsibility. Sustainable development can only be achieved when innovation is supported by collective action and a genuine commitment to environmental stewardship.

On this World Environment Day, let us move beyond conversations and take meaningful steps towards creating a cleaner, greener, and more sustainable planet. By embracing innovation, strengthening recycling ecosystems, and acting responsibly today, we can create lasting environmental impact and secure a better future for generations to come.

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Concrete

JK Lakshmi Advances LC3 Cement Expansion

Company highlights commercial production and research partnerships

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The meeting reviewed progress in limestone calcined clay cement (LC3) technology and its commercial adoption in India’s cement sector, focusing on low-carbon alternatives to conventional binders. JK Lakshmi Cement noted that limestone calcined clay cement can reduce carbon dioxide emissions by up to 40 per cent compared with conventional cement and said this reduction supports industry decarbonisation. The company highlighted that it was among the first two cement manufacturers in India to move LC3 into commercial production after the Bureau of Indian Standards approved the technology as a cement standard.

Vinita Singhania said the transition of LC3 from research to commercial production reflected collaboration between industry, academia and international institutions. Maya Tissafi acknowledged JK Lakshmi Cement’s role in advancing LC3 adoption in India and its contribution in taking the technology from laboratory trials to commercial implementation. Both representatives underlined the growing relevance of sustainable construction materials as India expands infrastructure and urban development.

The meeting explored continued collaboration with Swiss research institutions such as EPFL, EMPA and ETH Zurich alongside Indian academic partners and development organisations. JK Lakshmi Cement has been associated with the LC3 initiative since 2014 and worked with EPFL, IIT Delhi, IIT Madras, Development Alternatives and Technology and Action for Rural Advancement. The company conducted one of the earliest industrial trials of LC3 and recently announced commercial production of Green Pro LC3 cement from its Jaykaypuram plant in Rajasthan.

India remains the world’s second-largest cement producer and expansion of infrastructure, urbanisation and housing demand continue to support long-term sector growth, increasing interest in low-carbon technologies. The company reported an annual turnover of more than Rupees (Rs) 60 bn and current cement capacity of about 18 million (mn) tonnes (t) per annum, with a target of reaching 30 million (mn) tonnes (t) by 2030. Apart from grey cement, the company also makes ready-mix concrete, gypsum plaster, wall putty, primers, adhesives and fly ash blocks, and both sides concluded on the need for continued collaboration to develop sustainable construction solutions.

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