Multi-scale engineering of alkali-activated concretes for sustainable infrastructure

Lead Research Organisation: University of Leeds
Department Name: Civil Engineering

Abstract

Infrastructure is the foundation of the society and economy of every nation, and enables us to enjoy a high standard of living. Currently 3.5bn people live in urban areas, and this will continue to rise, particularly in developing countries, reaching 6.2bn people by 2050. The provision of infrastructure and housing poses great challenges to be resolved in the coming years, but also offers a unique opportunity to drive significant global change, with the development of cities and the improvement of living standards to eliminate poverty and promote social inclusion being essential for global economic growth.

The enormous amount of resources necessary to fulfil the world's infrastructure requirements, and the urgent need to mitigate climate change, mean that it is essential to move from traditional ways of providing infrastructure (which involve the use of cement, steel and other resources, and emit large volumes of CO2), to more sustainable ways. This will safeguard our future global society. The worldwide demand for Portland cement (a key component of concrete) has doubled in the past 10 years, to more than 4 billion tonnes per year, and this will continue to rise in the coming decades. This accounts for 8% of all worldwide CO2 emissions, and this could increase to as much as 25% by 2050. There is an urgent need for the UK, and the international community, to take up low-carbon best practices as we design and build infrastructure, so that significant reductions in carbon emissions can be achieved rapidly, and a shift towards a low-energy sustainable construction industry occurs.

This Early Career Fellowship research focuses on the design, characterisation and assessment of one of the most promising low-carbon candidates that can be used in place of Portland cement, to produce sustainable and durable concretes. These materials, called alkali-activated cements, can offer carbon emissions savings of 40-80% compared to Portland cement, when used to make a concrete with similar or better performance. However, despite this potential, the performance of alkali-activated materials in the field is unproven, and the processes that are now used for their production also face challenges that need to be resolved for the future-proofing of this technology. So, further research is urgently required to prove that these materials can be produced by sustainable processes using highly available resources, and then serve well under challenging conditions, over periods of decades or more. This particularly means that we must understand the ability of potentially damaging chemical species to move through alkali-activated cements (either through the material itself, or through any cracks which may form as the material shrinks or is damaged). This lies at the heart of the understanding of concrete durability, and requires the development of advanced modelling tools to predict the long-term performance of concretes that are made from these new cements, moving beyond the timescales that can be accessed in the laboratory to describe real-world performance.

The central aim of this Fellowship research is to provide the scientific basis for the use of the UK's natural resources, as well as by-products from other industries such as the production and processing of metals, to produce high-performance, high-durability alkali-activated concretes using conventional and/or novel processes. To achieve this, the Fellowship applicant and her team will use state of the art materials characterisation techniques to make connections between the way alkali-activated cements are produced, and their performance - moving the understanding 'from atoms to applications'. This will open a new pathway to building sustainable infrastructure for the future of the UK and worldwide, further strengthening the nation's current world-leading position in developing and using innovative cements, and opening opportunities for international connections and impact.

Planned Impact

The main beneficiary of this Fellowship research will be the construction industry, as this research will help remove barriers to the usage of alkali-activated cements and concrete in practical large-scale applications. Through partnership with the leading UK producer of alkali-activated/geopolymer cements, Banah UK, as well as European and global experts in waste valorisation, materials and construction technology such as FehS (Institut für Baustoff Forschung) and Zeobond Pty Ltd, impact will be optimised through direct transfer of results into application at all levels of the industry supply chain, from raw materials to finished products. Through partnership with these industry and commercial organisations, as well as the Swiss national laboratory EMPA (which is classified as an academic collaborator within the Fellowship research structure, but which nevertheless is extremely closely engaged with European and international industry), the Fellowship research results will be translated rapidly and effectively into state-of-the-art industry practice, in the UK and internationally.

The ability to accurately assess, predict and model the durability performance of alkali-activated cements and concretes, from a technically validated basis, will bring a very high degree of impact in both academic and industry circles. This information is the fundamental basis of performance-based standardisation, which are a crucial step to future development of standards enabling the use of innovative non-Portland cements in major infrastructure projects. The detailed modelling work which underpins this performance assessment will be disseminated through knowledge exchange workshops and direct engagement activities, including two specialised courses that will be delivered during the lifetime of the Fellowship research. The Fellowship team will also use these opportunities to gain input from partners and potential end-users regarding their priorities in terms of performance targets andkey degradation mechanisms for in-service applications, and will incorporate this feedback into the modelling work. The specific data underpinning these models will be made available to the developers of the international databases CEMDATA (thermodynamic data for cementitious systems), and SCEnAT and Ecoinvent (international references in the field of life cycle analysis) for inclusion in these widely used database tools, to maximise accessibility of the information to academic and industrial communities working on development and implementation of sustainable construction materials.

The Pathways to Impact plan also targets both social and technical aspects of implementing outcomes from the research in highly populated emerging countries such as Brazil, South Africa, India and Thailand through the current participation of the Fellowship applicant in Global Challenges Research Fund programmes. This will maximise the global impact of the Fellowship research, and will enable to identify future strategies for the development and application of alkali-activated materials, in different geographical regions. The academic aspects of this dissemination will also be linked to two major events, where the Fellowship applicant is part of the organising and scientific committees: ECI Second International Geopolymers Conference, Tomar (Portugal), May 2018, and the RILEM Week and Annual Cement and Concrete Science Conference, Sheffield (UK), September 2020, hosted jointly by RILEM Association and the Cementitious Materials Group of IOM3.

Publications

10 25 50
 
Description In the 9 months since this research fellowship programme commenced, we have dedicated out efforts in furthering our knowledge applying advanced imaging techniques (specificatly SEM and uCT) to the analysis of cementitious materials, using the facilities of the UKCRIC Centre of Infrastructure Materials housed at the University of Leeds. My team and I have commenced synthesis of low carbon cements, exploring alternative mix design to reduce carbon footprint, while controlling phase assemblage evolution. The first outcomes of detailed characterisation of these new alkali-activated materials will discussed in upcoming conferences in the UK and abroad, and based on those results we will initiate the scaled up production of concretes for durability testing.
Exploitation Route The preliminary research outcomes of this fellowship programme will be presented in upcoming national and international events (e.g. IOM3 Cement and Concrete Science Conference and International Congress on the Chemistry of Cement), to create awareness of the advanced my team and I have achieved in developing alternative alkali-activated cements using near neutral salt activators.
Sectors Construction

 
Description PERFoRM - Marie Sklodowska-Curie Individual Fellowship
Amount € 212,000 (EUR)
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 06/2019 
End 06/2021
 
Description Collaboration with Federal Institute for Materials Research and Testing (BAM - Germany) 
Organisation BAM Federal Institute for Materials Research and Testing
Country Germany 
Sector Public 
PI Contribution My team and I provide expertise in the area of alkali-activated technology, particularly in the development of alternative manufacturing routes to produce alkali-activated cements. As an extension of our research activities in this area, a recently funded Marie Sklodowska Curie Individual Fellow (Dr Juan Pablo Gevaudan), will study the interaction of steel with these novel materials, using a multi-technique imaging and spectroscopic approach using the UKCRIC Centre of Infrastructure Materials at University of Leeds, and will extend his research work evaluating the feasibility of applying newly developed electrochemical tests for assessment of steel corrosion in highly alkaline concretes.
Collaborator Contribution Colleagues at BAM will be hosting for 4 months a Marie Sklodowska Curie Individual Fellow (Dr Juan Pablo Gevaudan), who will be exploring the applicability of novel electrochemical techniques developed at BAM for the assessment of steel corrosion in highly alkaline environments. The objective of these secondment is to strengthen collaboration between colleagues at BAM and my team, including direct contribution to the activities both teams have committed to developed within the scope of the European Federation of Corrosion Task Group 11.
Impact The research activities of this collaboration will initiate in June 2019, hence we do not have output to report at this stage.
Start Year 2019
 
Description 2nd Meeting - RILEM TC 281- Carbonation of Concrete with Supplementary Cementitious Materials 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact The 2nd RILEM Technical Committee (TC) 281-CCC meeting was held in TU Delft, The Netherlands during RILEM week. This international TC bring together expertise from academia, industry, practitioners as well as policymakers on understanding the response of modern concretes when exposed to CO2. As Deputy-Chair of the TC and coordinator of the Working Group in Carbonation of Alkali-Activated Materials, I presented some of the published results in the topic, as well as the outcome of an international round robin evaluating the feasibility of adopting different testing conditions, for assessment of performance of these materials. The presentation of these results sparked questions and discussions particularly from industry participants, as it highlights the needs of creating more suitable testing methodologies to determine performance of alkali-activated concretes when exposed to CO2. This has aided in motivation for the development of a critical review currently under preparation compiling existing data in the topic.
Year(s) Of Engagement Activity 2018
 
Description Interview for The World - A co-production of the BBC World Service, Public Radio International and WGBH in Boston 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact This radio interview was centred in discussing greener alternatives infrastructure materials that can be used for production of sustainable concretes.
Year(s) Of Engagement Activity 2018
URL https://www.pri.org/stories/2018-07-19/concrete-production-uses-ton-sand-and-emits-lot-carbon-here-a...
 
Description Invited talk for the Microlab Colloquium - TU Delft - The Netherlands 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Around 20 academics, researchers and postgraduate students of the Faculty of Civil Enginering & Geosciences, as well as from the Netherlands Organisation for Applied Scientific Research (TNO) attended the Microlab colloquium, where I presented my research in utilising alkali-activated cements and concretes in extreme environments, such as encapsulation/ immobilisation of radioactive nuclear wastes. All attendees were very interested in the research outcomes presented, and made several questions about the chemistry of these materials and the advantages over other types of cementitious grouts. This discussion created major awareness of the applicability of these innovative cements in application beyond civil construction.
Year(s) Of Engagement Activity 2019
 
Description Invited talk for the Royal Academy of Engineering Research Day - Leeds City Region 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact I was an invited speaker at the Royal Academy of Engineering Research Day organised by the Faculty of Engineering at the University of Leeds, presenting the new trends in infrastructure materials for 'cementing the future infrastructure'. I particularly emphasised the key role of concrete in our societal development, and also the great opportunities to increase sustainability of future infrastructure by development and adoption of low-carbon cements, such as alkali-activated materials. Several members of the audience from industry were particularly interested in the research I am conducting in this topic, and the advanced characterisation techniques available in the UKCRIC Centre of Infrastructure Materials housed at the University of Leeds.
Year(s) Of Engagement Activity 2019
URL https://engineering.leeds.ac.uk/events/event/362/royal_academy_of_engineering_research_day_-_leeds_c...