LC3 – A Sustainable Alternative for the Cement Industry
Limestone Calcined Clay Cement (LC3) is a new low-carbon blended cement that allows cement manufacturers to reduce the CO2 emissions from production. Funding from the Swiss Agency for Development and Cooperation (SDC) helped bring the LC3 technology from the lab to large-scale commercial production. The SDC supported the development of the scientific basis for LC3 and the testing of production, and is promoting the adoption of LC3 standards and supporting global outreach.
*This weADAPT article is an abridged version of the original brochure, which can be downloaded from the right-hand column. Please access the original text for research purposes, full references, and to quote text. Available in English and in other language versions (Arabic, Chinese, French, Spanish) below.
Why does the cement industry need to change?
Concrete is the most widely used building material in the world, and its main component is cement. The chemical and thermal combustion processes involved in the production of cement are major sources of CO2 emissions, accounting for about 8 per cent of global CO2 emissions. Moreover, concrete is expected to have an important role in future emissions due to increasing urbanisation, particularly in Asia and sub-Saharan Africa.
To achieve a net-zero future, the construction sector needs to adopt sustainable, resource-efficient and circular approaches.
LC3 contributes to the reduction of CO2 emissions by reducing the energy intensive clinker * content through the addition of calcined clay and limestone. Depending on the type of cement that is replaced by LC3, the reduction in CO2 can reach up to 40 per cent.
Significant energy savings are achieved because calcined clays are more malleable and are heated at approximately 700-800 °C whereas the manufacture of clinker requires a temperature of 1400-1500 °C. LC3-50 with a clinker content of 50 per cent is widely promoted and accepted under cement standards applicable in Europe, India, the United States, Cuba and much of South America.
* Clinker: dark grey nodular material made by heating limestone and clay at a temperature of about 1400-1500 °C.
SDC engagement in developing and scaling-up low-carbon cement
The SDC has engaged with partners in India (the Indian Institutes of Technology in Delhi, Bombay and Madras and the Indian NGO Technology and Action for Rural Advancement) and Cuba (the Universidad de las Villas) contributing to the development, testing, production and dissemination of LC3. From 2020, Technical resource centres in Delhi and Santa Clara provide consultancy services to the industry (*see brochure for full timeline for research, application and scaling up).
SDC’s pioneering efforts and engagement on LC3 has established the environmental and economic viability of the technology, and has contributed to the integration of LC3 into policy and road maps for the decarbonisation of the building and construction sector. The map below shows the spread of LC3 across the globe.
“LC3 – A sustainable alternative for the cement industry” (2022), Swiss Agency for Development and Cooperation, Bern, www.sdc.admin.ch/publications.
Imprint Designed and copy-edited by: Zoï Environment Network