Self-healing concrete to increase service life of a roof plate for an inspection pit in the Oosterweel link : healing efficiency and preliminary service life estimation

To overcome difficulties linked to inspection of certain structural elements, as well as costs and hindrance related to manual repair of cracked concrete, the use of self-healing concrete has been proposed. Over the last few years, the efficiency of different self-healing mechanisms has been tested at laboratory scale. Mineral additions, crystalline admixtures, or superabsorbent polymers have been used to stimulate the autogenous self-healing capacity of concrete, whereas encapsulated polymeric compounds or bacteria have been applied to obtain autonomous selfhealing. Several of these self-healing agents have been upscaled by partners of the EC project HEALCON and tested in structural concrete elements in the laboratory. In August 2017, a demonstration project with microbial self-healing concrete has been established. The roof plate of a sewer inspection pit for the Oosterweel link in Antwerp was cast with concrete including a mixed ureolytic culture of bacterial spores, and urea and calcium nitrate as nutrients. Based on the expected closure of cracks, as obtained in laboratory experiments, the increase in service life of the plate in this corrosion exposed environment could be estimated. The behaviour of the concrete element in situ will be monitored regularly in the future