Smart cements: repairs and sensors for concrete assets

Smart cements offer a unique opportunity to unify our approach to the remote monitoring and repair of concrete assets. Here, we present our latest progress in manufacturing and testing smart cement sensor-repairs based on fly ash geopolymers - a novel class of cement-like binders that cure to a strong, chemically resistant, electrically conductive shell. Since chloride and moisture are two of the leading causes of degradation of reinforced concrete, we are proposing a technology that is able to monitor chloride ingress into concretes at different levels of moisture. The main task of the work was to manufacture geopolymer binders for concrete specimens, and to cure them at ambient temperatures. We have studied how practical considerations, such as the concrete substrate’s maturity, can affect how or whether smart cements can be applied, thus understanding the main limitations of the technology. By using electrical impedance measurements, we aim to demonstrate that geopolymer skin layers can provide high resolution monitoring of chloride contamination at different levels of moisture. Here we present results which show that smart cements are sensitive to changes in humidity of the surrounding environment. Our goal is to develop a robust and field-worthy technology which unifies civil monitoring and maintenance. This goal is of key national importance to the US and many countries within Europe, who now face an ageing population of reinforced concrete bridges, tunnels and support structures.