Concrete

Durable concrete for tunnelling application

Published

13 years ago

July 31, 2012

admin

In this first part of the two-part series, EugenKleen of Mc-Bauchemie Mueller GmbH and Co.KG spells out the properties required in concrete and the types of concrete used in tunnelling application.Over the decade the use of concrete admixtures, especially plasticizers and superplasticizers, is showing upward trend in India. The advent of concrete pumps and transit mixers has also contributed to this, as the use of superplasticizers enables trouble-free pumping operations and minimizes pipe blockages. With the advent of major metro projects across India, durability of concrete used especially for tunnelling segments is of prime importance. The earlier attitude of taking recourse to the use of admixtures only after facing problems is changing fast, and now, in most tunnelling projects, high performing admixtures are already included in the specifications and the mix is designed to achieve the necessary properties.The concrete for tunnel segments necessitates the concrete to have the following properties:??Compressive strength??Workability??Surface finish??DurabilityAs part of the durability requirements, concrete is or should be generally tested for the following properties:??Chloride migration??Sulfate resistance??Water absorption??Acid resistance??Porosity??Freeze thaw resistanceThis can be achieved using the latest technologies available for concrete. Concrete is now no longer a material consisting of cement, aggregates, water and admixtures but it is an engineered material with several new constituents like PFA, GGBSF, Microsilica, Metakaolin, Colloidal Sillica and several other binders, fillers and pozzolanic materials. The concrete today can take care of any specific requirements under most exposure conditions.The mix designs are getting relatively complex on account of interaction of several materials and mix design calls for expertise in concrete technology and materials. High performance concretes will have to be adapted for tunnelling segments, considering special properties as well as low cost maintenance strategies.What type of concrete do we use?Concrete used in tunnelling applications need the following outstanding properties viz. Compressive strength, high workability, enhanced resistances to chemical or mechanical stresses, lower permeability, durability etc. this will necessitate the use of high performance concrete. Some HPC types which will hold the key for tunnelling applications can be classified into:??Self compacting concrete / high workability concrete??Concretes resistant against aggressive mediaSelf-Compacting Concrete (SCC)Self-Compacting or Consolidating Concrete (SCC), as the name signifies should be able to compact itself by its self-weight under gravity without any additional vibrations or compaction. Self compacting concrete should be able to assume any complicated formwork shapes without cavities and entrapment of air. The reinforcement should be effectively covered and the aggregated should be fully soaked in the concrete matrix. In addition, the concrete should be self-levelling type and self-defoaming without any external compaction.The formulation of self compacting concrete has the latest concrete technology and it requires in-depth knowledge of materials and meticulous testing procedures before the concrete is designated as SCC. Self compacting concrete has the following special advantages.??Saving of cost on machinery, energy and personnel for vibrating the concrete??Considerable improvements to exposed surfaces (Fair Faced Concrete), less efflorescence??Marked improvements in durability on account of better compaction??Extremely suitable for slim and complicated moulds??Covers reinforcement effectively??Better adhesive between cement binder and aggregates??Reduction in de-moulding time??Advantage with respect to sound pollutionTherefore while calculating the costing and economics of self compacting concrete all the above mentioned advantages should be converted to cost parameters. This kind of concrete can give advantage of good compressive strength, workability and finish to the tunnel segments and may prove suitable.Durable concrete resistant against aggressive mediaOne major application of HPC is to increase the durability of concrete where aggressive underground conditions are anticipated. This can be achieved physically by resorting to very dense aggregate packing.Practically possible by selecting a very smooth sieve line from largest aggregate to the smallest grain of mineral additives like microsilica or new generation aluminosilicate slurries. Chemically, cement by itself is not acid resistant. The acid resistant binder is formed by combination of cement, microsilica / aluminosilicate and flyash. To control permeability very low water cement ratio has to be adopted. So as to provide the essential concrete properties a high-performance PCE (polycarboxylate ether) needs to be incorporated in the mix. By adjusting the particle size distribution on the micro scale the permeability of the concrete is reduced which minimizes the penetration of aggressive substances. Depending on the degree of dispersion these material particles more or less completely fill the spaces between the cement particles. During hydration the pozzolanic silica reacts with the free calcium hydroxide to form calcium silicate hydrates. This gives a denser concrete structure.(Source: Paper presented by the author at the Construction Chemicals International Conference 2012 held in Mumbai)

Concrete

Molecor Renews OCS Europe Certification Across Spanish Plants

Certification reinforces commitment to preventing microplastic pollution

Published

1 hour ago

December 18, 2025

admin

Molecor has renewed its OCS Europe certification for another year across all its production facilities in Spain under the Operation Clean Sweep (OCS) voluntary initiative, reaffirming its commitment to sustainability and environmental protection. The renewal underlines the company’s continued focus on preventing the unintentional release of plastic particles during manufacturing, with particular attention to safeguarding marine ecosystems from microplastic pollution.

All Molecor plants in Spain have been compliant with OCS Europe standards for several years, implementing best practices designed to avoid pellet loss and the release of plastic particles during the production of PVC pipes and fittings. The OCS-based management system enables the company to maintain strict operational controls while aligning with evolving regulatory expectations on microplastic prevention.

The renewed certification also positions Molecor ahead of newly published European regulations. The company’s practices are aligned with Regulation (EU) 2025/2365, recently adopted by the European Parliament, which sets out requirements to prevent pellet loss and reduce microplastic pollution across industrial operations.

Extending its sustainability commitment beyond its own operations, Molecor is actively engaging its wider value chain by informing suppliers and customers of its participation in the OCS programme and encouraging responsible microplastic management practices. Through these efforts, the company contributes directly to the United Nations Sustainable Development Goals, particularly SDG 14 ‘Life below water’, reinforcing its role as a responsible industrial manufacturer committed to environmental stewardship and long-term sustainability.

Concrete

Coforge Launches AI-Led Data Cosmos Analytics Platform

New cloud-native platform targets enterprise data modernisation and GenAI adoption

Published

1 day ago

December 17, 2025

admin

Coforge Limited has recently announced the launch of Coforge Data Cosmos, an AI-enabled, cloud-native data engineering and advanced analytics platform aimed at helping enterprises convert fragmented data environments into intelligent, high-performance data ecosystems. The platform strengthens Coforge’s technology stack by introducing a foundational innovation layer that supports cloud-native, domain-specific solutions built on reusable blueprints, proprietary IP, accelerators, agentic components and industry-aligned capabilities.

Data Cosmos is designed to address persistent enterprise challenges such as data fragmentation, legacy modernisation, high operational costs, limited self-service analytics, lack of unified governance and the complexity of GenAI adoption. The platform is structured around five technology portfolios—Supernova, Nebula, Hypernova, Pulsar and Quasar—covering the full data transformation lifecycle, from legacy-to-cloud migration and governance to cloud-native data platforms, autonomous DataOps and scaled GenAI orchestration.

To accelerate speed-to-value, Coforge has introduced the Data Cosmos Toolkit, comprising over 55 IPs and accelerators and 38 AI agents powered by the Data Cosmos Engine. The platform also enables Galaxy solutions, which combine industry-specific data models with the core technology stack to deliver tailored solutions across sectors including BFS, insurance, travel, transportation and hospitality, healthcare, public sector and retail.

“With Data Cosmos, we are setting a new benchmark for how enterprises convert data complexity into competitive advantage,” said Deepak Manjarekar, Global Head – Data HBU, Coforge. “Our objective is to provide clients with a fast, adaptive and AI-ready data foundation from day one.”

Supported by a strong ecosystem of cloud and technology partners, Data Cosmos operates across multi-cloud and hybrid environments and is already being deployed in large-scale transformation programmes for global clients.

Concrete

India, Sweden Launch Seven Low-Carbon Steel, Cement Projects

Joint studies to cut industrial emissions under LeadIT

Published

2 days ago

December 16, 2025

admin

India and Sweden have announced seven joint projects aimed at reducing carbon emissions in the steel and cement sectors, with funding support from India’s Department of Science and Technology and the Swedish Energy Agency.

The initiatives, launched under the LeadIT Industry Transition Partnership, bring together major Indian companies including Tata Steel, JK Cement, Ambuja Cements, Jindal Steel and Power, and Prism Johnson, alongside Swedish technology firms such as Cemvision, Kanthal and Swerim. Leading Indian academic institutions, including IIT Bombay, IIT-ISM Dhanbad, IIT Bhubaneswar and IIT Hyderabad, are also participating.

The projects will undertake pre-pilot feasibility studies on a range of low-carbon technologies. These include the use of hydrogen in steel rotary kilns, recycling steel slag for green cement production, and applying artificial intelligence to optimise concrete mix designs. Other studies will explore converting blast furnace carbon dioxide into carbon monoxide for reuse and assessing electric heating solutions for steelmaking.

India’s steel sector currently accounts for about 10–12 per cent of the country’s carbon emissions, while cement contributes nearly 6 per cent. Globally, heavy industry is responsible for roughly one-quarter of greenhouse gas emissions and consumes around one-third of total energy.

The collaboration aims to develop scalable, low-carbon industrial technologies that can support India’s net-zero emissions target by 2070. As part of the programme, Tata Steel and Cemvision will examine methods to convert steel slag into construction materials, creating a circular value chain for industrial byproducts.