Fostering the new generation of UHPFRC infrastructures in Canada: characterizing and modeling the effect of fibre orientation on the structural ductility

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While a large majority of concrete infrastructures in Quebec undergo to an advanced state of deterioration, it is now critical to consider the potentials of new composites for better designing the next infrastructure system in terms of material saving, longer life, reduced maintenance cost, faster construction and environmental friendliness. Among all the emerging composites, Ultra High Performance Concretes (UHPC) is becoming a truly breakthrough in civil engineering thanks to their outstanding properties. The driving force of UHPFRC is the structural ductility which has been achieved by means of the optimally designed fibre reinforcement. As a major consequence, ductility infers reduced crack widths and high durability. However, it was experimentally found that the remarkable ductility of UHPFRC structures can be completely lost when the fibres are mostly oriented in an unfavourable direction. The industrial implementation of UHPFRC is today limited by the lack of a reliable method which accounts for the effect of the fibre distribution. The project aims to develop a new model-based approach to foster innovative solutions of UHPFRC bridges by directly accounting for the fibres' mechanisms and distribution. The proposed research is based on a comprehensive approach which combines theory, experimental tests and computer simulation. The major research objective are: (i) to develop a new non-local damage model which can directly predict the ductility of UHPFRC structures from the fibre distribution; (ii) to provide a powerful engineering tool which can aid engineers to analyze UHPFRC structures; (iii) to provide a model-based reliability approach which will allow Canadian industries to engineer safe UHPFRC structures by mastering the uncertainty due to fibre distribution; (iv) to contribute to upgrade the first UHPFRC recommendation guidelines and to advance the harmonization with the Canadian Design Handbook. The value of the project results is to deep the current understanding of the role of fibre distribution in UHPFRC structures as well as to develop the needed tools and method to foster the implementation of UHPFRC in the next generation of Canadian infrastructure.