High-speed rail lines, at ever increasing speeds and distances, are in development both in the UK and world-wide, but up-front capital expenditure can potentially be a major inhibiting factor both to the client and also in the eyes of the public. Cost reductions for these lines could be achievable if the initial costs of the physical construction, the duration of construction and the land take could be reduced. All three of these costs can potentially be reduced for embankments if the industry were to move towards a novel embankment replacement system. In addition embankment replacement systems could significantly improve the performance of the track structure as the dynamic properties of the contained material can be better controlled. However, such technology requires significant performance evaluation and the development of appropriate design guidance before UK industry can justifiably implement it in a project. This project therefore aims to evaluate and produce design guidance for two novel embankment replacement systems as a means to potentially reduce the cost of constructing new high-speed railway lines (particularly in urban environments) and improve the overall track behaviour and hence passenger experience.

As the world moves towards zero emissions, decarbonising cement is often described as the most difficult challenge. Portland Cement, which is used to make concrete and mortar, is made in tremendous volumes (more than 500 kg per person per year for everyone on the planet), is cheap (~£60/tonne) and has excellent properties for construction. However, it causes a quarter of all the world's industrial emissions, both due to fuel combustion in high-temperature cement kilns, and because the chemistry of converting limestone into clinker, the key ingredient of cement, inevitably causes the release of carbon dioxide. Many alternative compositions of cement are under development, but although some may lead to reduced emissions, none have zero emissions. Two possible approaches to capturing and storing emissions are under development - one capturing all the emissions of a plant and storing them underground, and the other embedding emissions within pre-cast blocks - but neither is yet operating at scale, and both face many challenges. Without cement, we will have no concrete, and construction will have to change radically largely shifting from new-build to retrofit and adaption. Countries responsible for around 70% of the world's GDP have now committed to zero emissions targets by 2050 or 2060, so the problem of cement emissions is both large and urgent. This proposal explores the world's first process that could produce Portland cement with no emissions. The investigators noticed that the lime-flux used in today's electric steel-recycling furnaces has almost the same chemical composition as that of old cement paste - the material that is left when old concrete is crushed, and sand and aggregate is removed. In preliminary trials, using the small electric arc furnace of the Material Processing Institute, we replaced the conventional flux with used cement. We separated the hot liquid slag that floats on the surface of molten steel during recycling and cooled it to form a powder which we then mixed with gypsum and cast into small cement samples. Analysis of our tiny pilot study cement samples showed that they were very similar to conventional Portland cement. This points to the exciting possibility that we could make cement as a by-product of steel recycling, which could be powered by non-emitting electricity - therefore giving us both zero emissions steel and zero emissions cement. This proposal aims to explore the science around this discovery. We need to find out how the composition of old cement varies, and how this variation affects our new product. We need to explore what effect our new process has on conventional steel recycling - does it change the composition of the steel, does it damage the furnace lining, and how does the type of steel being recycled affect our new cement? And we need to find out more about the properties of our new cement: how durable is it, how quickly does it reach full strength, and so on. If this new process is as good as we hope, we will want to develop it rapidly to commercial scale, and the technique for making it could become a major UK export. The final component of our proposal is therefore to develop a "roadmap" for taking the idea from lab-scale trials to full deployment. We will explore this question with a consortium of partners, a science advisory panel, and with outward facing partners who could help us champion the new approach.

The latest report of Intergovernmental Panel on Climate Change (IPCC) 'Global warming of 1.5C' emphasises the need for 'rapid and far-reaching' actions now to curb carbon emission to limit global warming and climate change impact. Decarbonising heating is one of the actions which is going to play a key role in reducing carbon emission. The Committee on Climate Change states that insufficient progress has been made towards the low carbon heating homes target that requires immediate attention to meet our carbon budget. It is well known fact that the ground is warmer compared to air in winter and cooler in summer. Therefore our ancestors build caves and homes underground to protect them against extreme cold/hot weather. Geothermal energy pile (GEEP) basically consists of a pile foundation, heat exchanging loops and a heat pump. Heat exchanging loops are usually made of high density polyethylene pipes and carry heat exchanging fluid (water and/or ethylene glycol). Loops are attached to a reinforcement cage and installed into the concrete pile foundations of a building to extract the shallow ground energy via a heat pump to heat the building during winter. The cycle is reversed during summer when heat is collected from the building and stored in the ground. GEEP can play an important role in decarbonising heating as it utilises the sustainable ground energy available under our feet. High initial cost remains the main challenge in deploying heat pump technology. In the case of GEEP, the initial cost can be reduced, if the heat capacity of the concrete is improved and loop length can thus be decreased. This can be achieved by incorporating phase change material (PCM) in the concrete. PCM has a peculiar characteristic that it absorbs or releases large amount of energy during phase change (solid to liquid or liquid to solid). This project aims to develop an innovative solution by combining two technologies GEEP and PCM to obtain more heat energy per unit loop length which would reduce the cost of GEEP significantly. PCM has never been used with GEEP in the past, therefore obvious research questions that come to the mind are (1) how to inject PCM in concrete (2) what would be the effect of PCM on concrete strength and workability (3) how PCM would affect load capacity of GEEP as primary objective of the GEEP is to support structure (4) how much heat energy would be available (5) what would happen to the ground temperature surrounding GEEP (6) how much it would cost (7) whether it would reduce carbon footprint of concrete. We aim to answer all the above research questions by employing sustainable and environmental friendly PCM and impregnate it in light weight aggregates (LWAs) made with waste material (e.g. fly ash, slag, glass). There are three advantages of using LWAs made from waste: first LWAs will replace natural aggregate in concrete as natural aggregates are carbon intense, second LWAs are porous and light so they can absorb large amount of PCM and reduce the weight of concrete, third reuse the waste. Laboratory scale concrete GEEP will be made with PCM impregnated LWAs and tested under heating and cooling load to investigate thermal (heat transfer) and mechanical (load capacity) performance. Extensive experimental and numerical study will be carried out to design and develop novel PCM incorporated GEEP which can provide renewable ground energy for heating and cooling.

High-speed rail lines, at ever increasing speeds and distances, are in development both in the UK and world-wide, but up-front capital expenditure can potentially be a major inhibiting factor both to the client and also in the eyes of the public. Cost reductions for these lines could be achievable if the initial costs of the physical construction, the duration of construction and the land take could be reduced. All three of these costs can potentially be reduced for embankments if the industry were to move towards a novel embankment replacement system. In addition embankment replacement systems could significantly improve the performance of the track structure as the dynamic properties of the contained material can be better controlled. However, such technology requires significant performance evaluation and the development of appropriate design guidance before UK industry can justifiably implement it in a project. This project therefore aims to evaluate and produce design guidance for two novel embankment replacement systems as a means to potentially reduce the cost of constructing new high-speed railway lines (particularly in urban environments) and improve the overall track behaviour and hence passenger experience.