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.

We have found that soils in cities are more effective sinks for carbon than agricultural soils. Urban soils typically carry a burden of fine-grained materials derived from often a long history of demolition. These materials include cement dust, which contains calcium silicate minerals, and also lime (calcium hydroxide). What we have found is that calcium derived from these minerals combines rapidly with carbonate in solution, which ultimately is derived from two sources - plants or rainwater. The rate at which this process occurs is extremely rapid, typically 100 T CO2 are removed from the atmosphere for each hectare of ground monthly; that's in a patch of ground the size of a football pitch. The amounts of carbon stored in urban soils as a consequence of this process are around 300 T C per hectare (compared with 175 T C per hectare in agricultural soils), and this is achieved rapidly after demolition (within very few years). We want to make sure that construction activity takes advantage of these findings, to help compensate for the CO2 emissions that arise from burning fossil fuels, and to contribute to the UK's ambitious targets for reducing our emissions. The potential is there - if engineered soils are strategically and systematically designed to have a carbon capture function we believe that around 10% of the UK's 2011 CO2 emissions could be captured in this way, as part of normal construction activity. The costs involved are far less than energy and capital intensive CO2 scrubbing systems that are fixed to specific plant, such as a power station. What's more, the design involves a range of ecosystem services and involves broadening the concept of 'Carbon Capture Gardens', which we have found to be very acceptable among a wide range of stakeholders, as pleasant spaces are created that communities can enjoy and engage with. The proposed research is intended to address some significant questions: 1) Can we reproduce the soil carbonation process artificially, so we can be sure of the carbon capture value? 2) How can we validate the process, so that claims of carbon sequestration can be trusted? 3) Is the process genuinely worth doing, in the context of UK and global CO2 emissions reduction targets? 4) What effect does the process have on soils, especially their strength and ability to drain rainwater, thus preventing flooding? 5) What effect does this approach have on plant and animal communities? Will the plants that we want grow in ground that has been treated to optimize carbon capture? 6) How does this process fit in with existing regulations that affect brownfield sites? 7) Under what circumstances is the process economically viable, given the geographical controls on availability of materials? 8) Can individuals use this approach in their own gardens? During the project, we will work with a wide range of stakeholders, from industry, local authorities and environmental groups as well as academics. We will engage students in monitoring work as part of the dissemination process. All the work will be openly published in appropriate forms, and we expect to build a growing community network associated with the project.

Tree planting has been the most common woodland expansion strategy in the UK for many decades. Despite its many benefits, this approach is increasingly being questioned following overestimates of benefits, poor targeting and challenges in scaling-up tree planting at the level required to meet ambitious woodland expansion targets. Consequently, there is growing interest in incorporating 'natural colonisation' (allowing trees to colonise new areas naturally) into woodland expansion strategies, partly because it is assumed that naturally created woodlands will be more structurally diverse, ecologically complex and resilient than planted sites. Embracing natural colonisation as a complementary approach to tree planting has the potential to radically transform UK treescapes and unlock woodland expansion at scale. Tree planting and natural colonisation may be used in complementary and blended combinations across a landscape, depending on the local conditions and the benefits expected. However, we know very little about the socio-ecological consequences of creating woodlands through approaches incorporating natural colonisation. We also have a poor understanding of land managers' attitudes towards woodland creation approaches other than tree planting, and it is not clear which kinds of land managers do, or would, engage with woodland creation through alternative approaches incorporating natural colonisation, and why. Using an inter-disciplinary approach, we will explore agricultural land managers' attitudes towards woodland creation strategies spanning the planting to natural colonisation continuum. We will also quantify the differing ecological and social consequences of these approaches, and identify factors associated with woodland resilience. Finally, we will integrate socio-ecological evidence to demonstrate how tree planting and natural colonisation can be used in combination to scale-up woodland expansion for a range of objectives on agricultural land. We will focus on broadleaf, and mixed broadleaf and conifer, woodlands created in agricultural landscapes with varying degrees of land-use intensity (from intensive arable lowland to marginal grassland on the upland fringe) and surrounding woodland cover, as these factors are likely to influence stakeholder perceptions and socio-ecological outcomes of woodland creation methods. These landscapes represent a major portion of UK land area with potential for woodland expansion. We will exploit two unique and complementary networks of woodland sites across the UK to create a novel platform from which to assess stakeholders' perceptions and socio-ecological consequences of woodland creation approaches spanning the planting to natural colonisation continuum. These sites provide a rich data resource and access to a diverse range of land-mangers. TreE_PlaNat will provide the evidence base to inform how, where, and for whom different strategies along the 'planting' to 'natural colonisation' continuum can be used to meet Government woodland expansion targets. Stakeholder organisations, including NGOs, statutory agencies and industry, are embedded in this proposal as co-applicants and project partners, demonstrating the co-development of this project and facilitating implementation of our findings.