Swiss, Indian and Cuban researchers have come together to develop limestone calcined clay cement (LC3), which can help reduce the carbon dioxide emissions of cement by almost 30%.
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LC3 is a new type of cement that is based on a blend of limestone and calcined clay. LC3 can reduce CO2 emissions by up to 40%, is made using limestone and low-grade clays which are available in abundant quantities, is cost effective and does not require capital intensive modifications to existing cement plants.
The objective of the LC3-Project is, through research and testing, to make LC3 standard and mainstream general-use cement in the global cement market. The main research activities focus not only on specific thematic areas of cement research but also on production, environmental sustainability and cost effectiveness of this new cement.
With funding from the Swiss Agency for Development and Cooperation through its Global Programme in Climate Change, that has been able to bring the idea of the LC3-technology from the lab in Switzerland to all parts of the world.
How to produce LC3?
To produce LC3, existing equipment can be used. The production line has to be adjusted since Limestone and Calcined Clay are added. The LC3-blend consists of the following materials:
Clinker that needs to be burnt at very high temperatures between 1400 and 1500°C.
LC3-has been used in many different regions and different scales. Overall, more than 25 applications were already built with LC3. In Latin America, several applications have been built. They are mainly in Cuba but also in other countries. Among those applications are a LC3-house, testing sites in the sea, art sculptures and pavements.
In India, the most prominent project is the model Jhansi, India. This house is made 98% out of LC3 and it used 26.6 t of industrial waste (192 kg/sqm) and Saved 15.5 t of CO2 (114 kg/sqm). These CO2-savings are similar to the emissions of 10 passengers traveling by plane from Switzerland to South Africa.
Model house in Jhansi
But there are also numerous other projects in India. For example, the offices of the Swiss Agency for Development and Cooperation in the compound of the Swiss Embassy in Delhi were built with LC3-prefab materials. Furthermore, some roads, a check damn and pavements were built.You find a selection of these applications on the photos.
Swiss Embassy building in Delhi
Check dam in Orchha
Why go for LC3
LC3 saves up to 40% of CO2 as compared to Ordinary Portland Cement. Most of the CO2 comes from the clinkerisation process. Therefore, reducing the clinker factor and replacing it with SCMs is the fastest intervention to save high numbers of CO2.
Within the clinker production, there are two main sources of CO2. Firstly, clinker needs to be burnt at very high temperatures between 1400 and 1500°C.
Secondly, CO2 embodied in limestone is released during production. Reducing the clinker content therefore means to save both energy-related and emobied CO2.
High performance For more than 10 years, the prestigious research institutes EPFL, IIT Delhi and Madras and CIDEM have tested LC3 in all different aspects and came to the result LC3 reaches OPC - CEM I performance.
Not only in lab conditions but also through industrial trials and applications these findings were confirmed. They are constantly monitored in existing LC3-applications in different parts of the world and environments (e.g. marine or high-altitude applications).
Overall, the production cost can be up to 25% lower for LC3 than for OPC due to savings for energy and material. This is without additional policy incentives, such as green funds or carbon certificates, which can further increase the attractiveness for cement producers.
The already existing readiness of the technology for the industrial uptake is an important distinction compared to other green technologies.
Furthermore, LC3 can be used without additional training by builders. In India, demo constructions were built without further providing training.
Source: LC3
LC3 Technology Resource Centre (LC3TRC)
The LC3 Technology Resource Centre (LC3TRC) in India has been set up by TARA, the social enterprise wing of the Development Alternatives Group with the purpose of providing access to state-of-the-art knowledge on LC3 and related products to industries and academia. Unique value proposition offered by LC3TRC is the delivery of comprehensive low carbon solutions to cement companies, pre-fab enterprises and clay calciners in India and abroad. Equipped with modern equipment, testing facilities and scientific personnel, the centre will provide consultancy services for establishing feasibility of LC3 in cement production and testing facilities for use of LC3 in concrete and concrete applications; material characterisation and calcination for use of clay resources in LC3 formulation. The centre is also equipped to supply LC3 based certified materials to research institutions. Research partners of LC3TRC include premier research institutions such as Indian Institute of Technology Delhi, Indian Institute of Technology Madras, Indian Institute of Technology, Bombay and École Polytechnique Fédérale de Lausanne (EPFL), Switzerland. Implementation partners include Centro de Investigación Desarrollo de Estructuras Materiales (CIDEM) Cuba and Technology and Action for Rural Advancement (TARA) India. Industrial collaborators include J.K. Lakshmi Cements Ltd, Dalmia Bharat Cements Ltd and Supertech Ltd.