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Engineered Calcium-Silicate-Hydrates for Applications

Periodic Reporting for period 2 - ERICA (Engineered Calcium-Silicate-Hydrates for Applications)

Reporting period: 2019-11-01 to 2022-02-28

Inorganic hydrates such as calcium-silicate-hydrate, calcium-alumino-silicate-hydrate (C-A-S-H) and magnesium-silicate-hydrate (M-S-H) are materials that can be produced in almost any shape or form, cheaply and in large quantities right across the world from local and sustainable resources. C-S-H is the “glue” of cement, itself the glue of concrete and, although this is by far the greatest application in terms of economic impact and volume (3.6 giga-tonnes of cement each year globally), there are many others. Hydrates have uses in paper, polymer composites, dentistry, waste water treatment, agriculture and nuclear waste encapsulation.

At project outset, little was known about how to engineer these hydrates for specific applications, e.g. construction requires use of locally available raw materials, decent strength after one day and low CO2 impact, while dentistry requires biocompatibility, “setting” within minutes and strength build-up within a few hours. There was no accepted understanding of: how hydrates grow and hence how to control growth; hydrate structure at the nano-scale; the changes in structure after drying and re-wetting; how water and deleterious small ions move into hydrates.

ERICA’s technical objectives were hence to:

discover how C-S-H nucleates and grows;

show that C-S-H can be engineered at the nano-scale;

evidence what happens at the nanoscale during the first and subsequent water sorption cycles;

elucidate how this impacts water and small ion transport in agglomerates of hydrates;

validate improved materials and production methods for real-world applications;

An equally important objective was to recruit and train a new generation of materials researchers fluent in these emergent technologies who could enter the industries that make and use these materials and carry forward the know-how.
ERICA’s objectives have been achieved through recruitment, training and research of 13 Early-Stage Researchers (ESRs) across 8 work packages. At the end of the project, significant progress has been made with the research objectives. In particular

Very substantial progress was made that has enabled routine and large-scale laboratory synthesis of hydrates with controlled and reproducible formulation (e.g. C/S ratio).

Cavitation is a process whereby vapor bubbles start to form in liquids - the role of cavitation of water in cement nano-pores was shown to be a critical phenomenon in drying cement.

Cement is recognised as a “hard” material but at the nanoscale it is much “softer”. A new model of water sorption in cements was introduced combining equations of fluid flow with microscopic changes in hydrate structure. Structural changes were found to occur on different timescales. The model was validated using specialist magnetic resonance imaging (MRI) normally used for clinical diagnosis. New lattice-Boltzmann algorithms helped understand the phenomena.

In collaboration with industrial Partners, a portable MRI system for the in-situ analysis of concrete was built, commissioned and shown to work much better than previous attempts.

We increasingly understand cement at the nano, micro and macro scales. However, linking the different pictures into a coherent whole is challenging. Significant progress was made in learning how to turn nanoscale “recipes” into macroscale measurable properties.

Methods available for multiscale modelling of mechanical properties of cementitious materials were extended and applied to link properties of microstructural constituents (solid material phases, pores) to macroscopic "homogenized" properties of cementitious materials, both in construction and dentistry.

A numerical model for understanding MRI images of cement was converted into a user-friendly publicly-available app.

Significant progress was made in understanding production of low CO2 cements ready for large scale production by industrial partners.

ERICA trained 13 researchers ready to find employment with cement product manufacturers, instrumentation manufacturers and in academia. They received comprehensive academic and transferable skills training comprising 6 Residential Schools, 14 Workshops and industry secondments. Training and dissemination were delivered in collaboration with European and global industry-academic cement science networks Nanocem and Innovandi, respectively.

ERICA mitigated the impact of the Covid pandemic on both training and research. Most formal training was complete before the pandemic struck widely. Research was impacted differently in different Beneficiaries but all ESRs were able to continue either their original, or a modified, line of research, often involving more modelling. Travel between Beneficiaries and Partners was largely prohibited which prevented some networking, dissemination at conferences, and a large fraction of the ESRs’ industry placement programme. ESRs benefitted alternatively from exposure to the industrial research environment in several ways: frequent interaction with their industry supervisors at ERICA meetings; some industry Partners continued work started by ESRs and sent results and samples back to the ESRs in academia; and some ESRs were granted extensions and continued secondments at the end of their projects. ESRs were also able to interact with a wide range of industrials through the Europe/Global academic-industry Nanocem and Innovandi consortia ( ).
A major output of ERICA is a Massive Online Open Course (MOOC) focused on water and water transport in cements and concretes, targeted towards BSc/MSc level graduate scientists entering the cement industry and/or early-stage cement researchers: see . This adds to an earlier MOOC on cement materials science created through H2020-MSCA-ITN Transcend (GA 264448).

To disseminate ERICA outputs, the ESRs created 5 videos and 13 factsheets that present research summaries, distributed through the ERICA website. ESRs were mentored by outreach professionals to develop activities to promote science and engineering to school age students, conveying the excitement of science and engineering in general and about cements and the need to reduce cement CO2 in particular.

A particular feature of ERICA was its adoption of magnetic resonance imaging and Lattice Boltzmann modelling for characterisation and understanding of cement materials. Specific actions to promote uptake of both include: Production of a Good Practice Guide for using MRI in cement science promoted through the ERICA website and Innovandi; Creation of open source software to implement the 3-tau model of NMR relaxation analysis in porous media such as cements: see ; and for lattice Boltzmann modelling of water sorption in cement: see .
ERICA ESRs with a group of school students at outreach session, Univ. of Surrey, UK, 25 July 2019