Keeling Curve

Project Summary / Description:

Cement production is one of the most carbon intensive industrial activities. To date manufacturing of cement produced more than 40 Gt CO2. When making cement, the high temperature calcination of carbonate minerals (e.g., limestone rocks: CaCO3) produces clinker (mainly calcium oxide: CaO), and CO2 is released into the atmosphere. Such process produces approximately 5% of global total CO2 emissions. 

However, our previous study (Nature Geoscience 2016, 9 880-883) suggested that gigatons of CO2 that is actually absorbed back into cement as it ages and degrades, through a process called carbonation. With the natural weathering effects, carbonation of cement materials in 80 years represents a large and growing carbon sink that offset 45% of the CO2 emissions from production of cement. The full carbonation of cement materials during long term weathering could offset almost 100% of CO2 emissions from cement production.

Given such potentials, the project aims to evaluate the possibility to reuse and recycling the carbonated cement materials for new constructions. Currently almost of cement materials have been discharged to landfill and buried with environmental conditions limit the further carbonation. Cement materials (Concrete and Mortar grains) as main building contents can be reuse and cycling for new building. Though the reuse and recycling of cement materials, the carbonation rate can approaching its maximum of 100% given the loner exposition, this could avoid the CO2 emission from additional production of cement. The reuse and recycling will also considerably reduce the CO2 related with energy consumption in during the cement production process.

Best Estimate of GHG Avoidance/Reduction of This Project (Tonnes CO2 Equivalent/Year):

Mission Statement:

Dr. Liu‚ lab based on scholars world prestigious universities, aims at the cutting edge studies to identify credible, affordable and practical solutions to quickly cut greenhouse gas emissions at global scale. With the supports from Caltech, Harvard, Research Council UK, Newton Fund, the National Natural Science Foundation of China, Chinese Academy of Sciences, for the past 5 years Dr. Liu‚ team have conducted world influential studies by using cross-cutting social-economic and applied physics measurements and big data technology to quantify the carbon emissions from industry (Nature, 2017, 524, 335-338), investigating carbon emissions and other indicators of water security, air pollution, resource consumption (Nature Climate Change 2017, 7, 75-80), and the impacts on human health (Nature 2017, 543, 705-709). Dr. Liu‚ team has built up broad connections with academia, industry and government, with a combination of expertise across the natural, social, and engineering sciences, Dr. Liu team is in an uniquely positioned to deliver knowledge and technology on climate mitigation technologies and strategies.

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Some media reports on the background of the project idea: Report by Science:http://www.sciencemag.org/news/2016/11/cement-soaks-greenhouse-gases Report by California Institute of Technology: http://www.caltech.edu/news/weathering-cement-important-overlooked-sink-carbon-dioxide-53134 Report by Yale University: https://www.yaleclimateconnections.org/2017/02/your-sidewalk-is-soaking-up-carbon-pollution/