Materials for Life (M4L): Biomimetic multi-scale damage immunity for construction materials

The resilience of building and civil engineering structures is typically associated with the design of individual elements such that they have sufficient capacity or potential to react in an appropriate manner to adverse events. Traditionally this has been achieved by using 'robust' design procedures that focus on defining safety factors for individual adverse events and providing redundancy. As such, construction materials are designed to meet a prescribed specification; material degradation is viewed as inevitable and mitigation necessitates expensive maintenance regimes; ~£40 billion/year is spent in the UK on repair and maintenance of existing, mainly concrete, structures and ~$2.2 trillion/year is needed in the US to restore its infrastructure to good condition (grade B). More recently, based on a better understanding and knowledge of microbiological systems, materials that have the ability to adapt and respond to their environment have been developed. This fundamental change has the potential to facilitate the creation of a wide range of 'smart' materials and intelligent structures. This will include both autogenous and autonomic self-healing materials and adaptable, self-sensing and self-repairing structures. These materials can transform our infrastructure by embedding resilience in the components of these structures so that rather than being defined by individual events, they can evolve over their lifespan. To be truly self-healing, the material components will need to act synergistically over the range of time and length scales at which different forms of damage occur.

Conglomerate materials, which comprise the majority of our infrastructure and built environment, form the focus of the proposed project. While current isolated international pockets of research activities on self-healing materials are on-going, most advances have been in other material fields and many have focussed on individual techniques and hence have only provided a partial solution to the inherent multi-dimensional nature of damage specific to construction materials with limited flexibility and multi-functionality. This proposal seeks to develop a multi-faceted self-healing approach that will be applicable to a wide range of conglomerates and their respective damage mechanisms. This proposal brings together a consortium of 11 academics from the Universities of Cardiff, Bath and Cambridge with the relevant skills and experience in structural and geotechnical engineering, materials chemistry, biology and materials science to develop and test the envisioned class of materials. The proposed work leverages on ground-breaking developments in these sciences in other sectors such as the pharmaceutical, medical and polymer composite industries. The technologies that are proposed are microbioloical and chemical healing at the micro- and meso-scale and crack control and prevention at the macro scale. This will be achieved through 4 work packages, three of which target the healing at the individual scales (micro/meso/macro) and the fourth which addresses the integration of the individual systems, their compatibility and methods of achieving healing of recurrent damage. This will then culminate in a number of field-trials in partnership with the project industrial collaborators to take this innovation closer to commercialisation.

An integral part of this project will be the knowledge transfer activities and collaboration with other research centres throughout the world. This will ensure that the research is at the forefront of the global pursuit for intelligent infrastructure and will ensure that maximum impact is achieved. One of the primary outputs of the project will be the formation and establishment of a UK Virtual Centre of Excellence in Intelligent Construction Materials that will provide a national and international platform for facilitating dialogue and collaboration to enhance the global knowledge economy.

The development of a new class of intelligent construction materials through the proposed high level academic research, by the academic investigators, as well as addressing scale-up, commercial and cost aspects through the extensive network of the project's industrial collaborators, is expected to have direct and significant economic and social impacts on the wide range of stakeholders involved in current and future development of our civil engineering infrastructure and the built environment. The proposed developments are expected to achieve significant reductions in whole-life costings of projects, by significantly reducing maintenance and repair costs; a 15% reduction could amount to over £5 billion/annum. The development of such resilient materials which will significantly enhance and extend the life of structures will lead to significant reductions in the production and use of cements and aggregates and hence will significantly reduce their impacts (~8% of global anthropogenic CO2 emissions from the ~2.8 billion tonnes/year and ~100 million tonnes/year extraction of natural resources for cement and aggregates respectively which also constitute a large proportion of construction and demolition waste of ~20 million tonnes/year). The beneficiaries include:
(i) all those involved with construction materials, products and systems: material suppliers, consultants, contractors, clients, architects, planners, local authorities;
(ii) civil engineering consultants and contractors who: (a) are involved in asset management and support for a wide range of infrastructure projects; (b) are involved in the design, construction, management and maintenance of different types of relevant structures: underground structures in strategically important installations e.g. tunnels and waste repositories; high risk infrastructure projects such as nuclear decommissioning and installations and those in highly aggressive environments: off-shore installations and energy related (geothermal, geological sequestration) installations; (c) put sustainability at the heart of their projects and see resilient materials as a key component of sustainable development, and those who have to meet sustainability targets.
They will all benefit by being directly involved in the project activities, with the opportunity to influence the research and to improve the performance of construction materials and their design. Such innovations will also provide them with a leading edge over competitors;
(iii) government and policy makers who have the mission to embed carbon and energy reductions in infrastructure and built environment developments and to reduce the whole life costs of infrastructure and local government who have the responsibility for the management and maintenance of their stock of infrastructure and built environment structures; where such developments will have a direct impact on their efficiency and cost reductions;
(iv) UK companies working abroad, including China with their significant construction growth, as well as in parts of the world where particularly aggressive construction conditions exist e.g. construction in highly saline soils in the Middle East;
(v) Research and development organisations who will be able to work closely with the consortium and to take forward innovations to commercial scale applications;
(vi) those groups involved in design codes and standards by the provision of sufficient data and field evidence of performance to enable a move towards incorporation;
(vii) Professional engineering institutions by raising the profile of UK civil engineering research with allied research fields and industrial sectors;
(viii) the wider public by significantly reducing delays and disruptions and costs to them through fewer maintenance and repair activities and the production of a greener infrastructure with much reduced environmental impacts; as well as school pupils will also benefit from the public outreach initiatives proposed.