Speaker: Professor Yun Bai
Time: 15:30,Jan.3th, 2024
Venue: Room 205, Building 14, Wushan Campus
Abstract：
The embodied carbon dioxide (ECO2) of Portland Cement is around 830 kg/t and the global cement manufacture accounts for 5-8% of the CO2 produced by mankind annually. Replacing Portland cement clinker with supplementary cementitious materials (SCMs), such as fly ash and ground granulated blastfurnace slag (GGBS), is an effective approach to reducing the ECO2 of cement, because they have much lower ECO2 than cement (10 kg/t for fly ash and 52 kg/t for GGBS). However, the production of fly ash and GGBS is rapidly diminishing in the UK due to the decline of relevant industry. Alternative sources of SCMs are, therefore, desperately required to sustain the UK's production of low carbon cements. Clay is a raw material common to three foundation industries, namely, cement, ceramics and paper. Higher-grade clays such as China clay are extracted for the manufacture of white ceramics and paper. Medium-grade clays are extracted to manufacture ceramics such as bricks and tiles, whereas lower-grade clays are extracted and utilised by the UK cement industry to produce Portland cement clinker. Waste derived clay material is generated during the extraction of higher-grade clays and through the production and use of medium-grade clays (waste bricks/brick fines). In an attempt to address the issues faced by UK construction industry due to the shortage of fly ash and GGBS in the U.K., a multi-disciplinary consortium sponsored by a £1.4M Innovate UK ISCF TFI large collaborative R&D project is currently exploring the potential of turning waste derived low-grade clays into alternative SCMs to develop novel low-carbon cements. The results show that the UK clays contains a variety of clay minerals (e.g., kaolinite, illite and montmorillonite) and the type and content of these mineral vary depending on their origin. In addition, considerable amounts of impurities also exist, including calcite, quartz and pyrite. As a result, most of these clays showed low reactivity. However, under optimal calcination conditions, the reactivity of these low-grade UK clays can be enhanced, showing comparable, and even better, performance in compressive strength than fly ash blended cement. This presentation will report the current progress, issues and challenges. The opportunities of developing low-carbon cements with calcined low-grade clays will also be discussed.
Biography of Invited Speaker：
Professor Yun Bai joined UCL as a Senior Lecturer in Materials in February 2012 and then promoted to Reader in Materials in October 2014 and Professor of Construction Materials (Chair inConstruction Materials) in October 2018. Prior to his appointment at UCL, he worked as a Civil Engineer in Ningxia Transport Department in China between 1993-2000, a PDRA in The Immobilisation ScienceLaboratory (ISL) at Sheffield University between 2004-2007, a Lecturer in Civil Engineering at Queen's University Belfast between 2007-2011. He is an elected Fellow of The UK Higher Education Academy (FHEA), The Institute of Concrete Technology (FICT) and The Institute of Materials, Minerals and Mining (FIMMM). Featured with ‘industry driven and interdisciplinary’, Professor Yun Bai developed his research at the interface between materialsscience and engineering applications, with a research scale ranging frommacro-level to micro- and meso- levels. Hiscurrent research activities mainly lie in the area of: 1) novel, low-carbonand low-energy cementitious materials; 2) durability of concretestructures; and 3) immobilisation of nuclear wastes using cementitiousmaterials.