SENSOR-INFRA: Smart Engineered Cementitious Composites for Intelligent Infrastructure

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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.