Advanced composites have been used extensively in high performance lightweight applications ranging from aerospace, automotive to renewable energy sectors, with a global market of composite products over £60bn by 2017 together with a compound annual growth rate of 7% since 2011, and a projected £10bn growth in sales of composites in UK industry by 2030. However, with the ever increasing demand for zero-impact and sustainable development, the environmental impact of each stage from composite production to their end-of-life options should be considered to take the advantage of this high growth rate in the composite sector. Three important questions remain for the clean growth of the sector: (1) how can we manufacture the composites in an environmentally sustainable way, i.e. reduce the energy consumption for the rapid growing production needs; (2) how to effectively reduce, recycle, and reclaim valuable materials from end-of-life composite wastes; (3) how to truly reveal the lightweight feature of composites and reduce the overdesign in composites while avoiding unexpected catastrophic structural failures. This project will address all three questions by materials and manufacturing innovation, creating a circular economy for the composite industry by providing an extremely energy efficient and intrinsically safe manufacturing method based on recycled composite wastes as new functional fillers. With only 1% of energy consumption compared to current manufacturing methods, high performance composites with integrated new functions like deformation and damage sensing as well as de-icing will be manufactured without needs of even an oven. This new method will be tuned to fully comply with the processing requirements of existing high performance composite systems, reducing costs in capital investment, operational, and maintenance aspects. The new functions will also provide real-time health monitoring of components' structural integrity to enable condition based maintenance with high reliability. This research will be supported by a strong joint force from both academia (WMG, University of Warwick, and Massachusetts Institute of Technology, US) and UK industry (ELG Carbon fibres Ltd, and LMK Thermosafe Ltd), with leading expertise from polymer and nanocomposite processing, smart composites, to carbon fibre recycling and intrinsically safe heating applications, to ensure a great success of the project and a large impact on relevant research fields, as well as a direct contribution to addressing the UK Grand Challenges of "clean growth" and "future of mobility" and international competitiveness of the UK economy, with world leading development in lightweighting in transportation, manufacturing and efficient use of resources.

Advanced composites have been used extensively in high performance lightweight applications ranging from aerospace, automotive to renewable energy sectors, with a global market of composite products over £60bn by 2017 together with a compound annual growth rate of 7% since 2011, and a projected £10bn growth in sales of composites in UK industry by 2030. However, with the ever increasing demand for zero-impact and sustainable development, the environmental impact of each stage from composite production to their end-of-life options should be considered to take the advantage of this high growth rate in the composite sector. Three important questions remain for the clean growth of the sector: (1) how can we manufacture the composites in an environmentally sustainable way, i.e. reduce the energy consumption for the rapid growing production needs; (2) how to effectively reduce, recycle, and reclaim valuable materials from end-of-life composite wastes; (3) how to truly reveal the lightweight feature of composites and reduce the overdesign in composites while avoiding unexpected catastrophic structural failures. This project will address all three questions by materials and manufacturing innovation, creating a circular economy for the composite industry by providing an extremely energy efficient and intrinsically safe manufacturing method based on recycled composite wastes as new functional fillers. With only 1% of energy consumption compared to current manufacturing methods, high performance composites with integrated new functions like deformation and damage sensing as well as de-icing will be manufactured without needs of even an oven. This new method will be tuned to fully comply with the processing requirements of existing high performance composite systems, reducing costs in capital investment, operational, and maintenance aspects. The new functions will also provide real-time health monitoring of components' structural integrity to enable condition based maintenance with high reliability. This research will be supported by a strong joint force from both academia (WMG, University of Warwick, and Massachusetts Institute of Technology, US) and UK industry (ELG Carbon fibres Ltd, and LMK Thermosafe Ltd), with leading expertise from polymer and nanocomposite processing, smart composites, to carbon fibre recycling and intrinsically safe heating applications, to ensure a great success of the project and a large impact on relevant research fields, as well as a direct contribution to addressing the UK Grand Challenges of "clean growth" and "future of mobility" and international competitiveness of the UK economy, with world leading development in lightweighting in transportation, manufacturing and efficient use of resources.

Current global infrastructure is plagued by ageing and deterioration and the scale of investment needed for maintaining its functionality is immense. With many nations having entered an era of austerity and financial restraint, the demand for infrastructure life-extension is currently more prevalent than ever. In these countries, however, asset owners have difficulties managing their infrastructure due to the absence of reliable data about the true 'state of health' of their assets. The proposed research centres on the development of engineered cementitious composites with a built-in self-monitoring system termed smart-ECCs (s-ECCs). This self-monitoring feature can provide future civil engineering infrastructure with a 'brain and nervous' system, enabling structures to sense and respond to the internal changes and external environment without the need of additional sensors. Furthermore, introducing 'smartness' to ECCs could also give the material a number of non-structural applications thereby making the material multi-functional. The research proposed will provide a comprehensive study of the rheological, mechanical and a.c. electrical properties of s-ECCs. It will be the first to undertake a detailed study into the electrical properties of ECCs from initial gauging, throughout setting and long-term hardening and into its piezo-resistive response under mechanical and environmental loading. A fuller understanding of these technical aspects will allow development standarised test protocols that can be further implemented in real-world applications. The novelty of the proposed research lies in the use of recycled, milled carbon (MC) fibres as conductive filler in ECC systems. As the length of MC fibres is equivalent to the characteristic crack width of ECCs, it is anticipated that the fibres will not bridge the micro-cracks in ECC, allowing the material sensitivity to cracks formation to be maintained thereby fulfilling its function as a damage sensor. At the same time, the high aspect ratio of MC fibres would allow the formation electrical continuity within the ECC matrix at practically low dosage rates. This is 'percolated' fibre network is essential to ensure that the influence of hydration and moisture changes in the material will not have appreciable influence on the bulk conductivity thereby minimising false sensing.

Continuous carbon fibre composites are capable of competing directly with advanced metals in terms of structural performance. The advantages of composites come from the ability to manufacture complex shapes, generally in relatively low volume production, in weight saving and corrosion resistance. However, continuous fibre composites are difficulties to manufacture, leading to both high costs and to the potential for generation of a range of defects impacting strongly on performance. In addition, continuous fibre composites cannot be directly recycled as there is no way of reusing the fibres that can be extracted in long, but not continuous and topologically ordered form. From an examination of the current status of the composites industry two big challenges can be identified. The first is to increase defect-free production volumes by at least an order of magnitude - leading directly to the need to simplify and automate the manufacturing processes [12]. The second is the requirement to generate more sustainable composites solutions by moving towards a circular economy based model [13] via the development of recycling processes able to retain the material's mechanical properties and economic value. In principle, there is nothing new in this analysis of the challenges, however, a great deal of research activity has been expended in these areas in the last two decades without achieving a step-change in capability. The central thesis of this proposal is that the principal difficulties in both achieving low cost, reliable, high volume production and readily recyclable advanced composites arise from a single source: the fact that the fibres are continuous and that both problem areas can be directly tackled by adopting highly Aligned Discontinuous Fibre Reinforced Composites (ADFRCs). Our vision is to generate a fundamental step-change in the composite industry by further developing and applying the HiPerDiF (High Performance Discontinuous Fibre) technology to produce high performance ADFRCs. This new, high volume manufacturing method was invented at the University of Bristol in the EPSRC funded HiPerDuCT (High Performance Ductile Composite Technology) programme (EP/I02946X/1). The basic concept is that if discontinuous fibres are accurately aligned and their length is significantly longer than the critical fibre length, the tensile modulus, strength and failure strain of the obtained composites are comparable to those of continuous fibre composites. This technique, developed in the HiPerDuCT programme has also shown the potential to tailor mechanical behaviour of composite materials, delivering pseudo-ductility via hybridisation and fibre pull-out mechanisms. The HiPerDiF technology offers the opportunity to realise the potential of aligned discontinuous fibre composites and produce a significant industrial and societal impact. Changing the fibre reinforcement geometry from continuous to discontinuous, without compromising the mechanical properties, will have a wide impact on the composite industry. The fibre discontinuity will allow an increase in the productivity of automated manufacturing processes and the formability of complex geometries, reducing the manufacturing generated defects. The use of ADFRC will increase the tailorability of composite materials by leading to truly multifunctional composite materials, able to respond to multiple design requirements. ADFRC will open the way for the adoption of a circular economy model in the composite sector by allowing the remanufacturing of reclaimed carbon fibres in high performance and high value feedstock and by producing more readily recyclable materials.

Breakthroughs in the development of new materials have historically been achieved largely by trial and error. My vision is that there is a new generation of advanced hierarchical materials that has never been addressed and can be achieved by design. This new generation draws inspiration both from recent experimental observations in existing materials and from biomimetics, and is made possible by recent advances in modelling and manufacturing. The main challenges faced by today's composites industry include (i) damage tolerance, (ii) manufacturability and (iii) sustainability. I argue that (i) hierarchical micro-structural designs for composites will be more damage tolerant and achieve over 100% increase in fracture toughness, (ii) that hierarchical discrete carbon-fibre systems will simultaneously address manufacturing and performance needs of the automotive industry, and (iii) that recycled carbon fibres will find a high-value market as semi-structural parts by also exploiting hierarchical architectures. My proposal is to define these hierarchical micro-structures by design and to then develop suitable manufacturing methods to realise them in practice.