Characterization of DURA-preblended UHPC for bridge construction according to the CHBDC standards

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Ultra High Performance Concrete (UHPC) is an emerging class of very resilient fiber reinforced cementitious materials that can be used to mitigate the durability and limited-service life issues faced by Canadian Bridges and other infrastructure exposed to aggressive environments. Due to dense packing, UHPC has very few connected capillary pores so that ingress and diffusion of water and chlorides is much slower than in conventional concrete; distributed steel fibers with a high aspect ratio delay the occurrence of crack localization enabling spectacular tensile strain capacity without strength loss. In the Canadian Market there are only few available UHPC products whereas the Canadian Highway Bridge Design Code Committees are engaged in establishing procedures for quality control of UHPC materials for implementation in bridge construction- the draft document, known as Annex S(A23.1) is about to be enforced. Facca is a Canadian Company that produces a unique material, DURA-UHPC, produced entirely with raw materials quarried in Canada. The challenge faced by the industrial partner in order to use DURA-UHPC in bridge construction is to demonstrate through physical modeling of mechanical and aggressive exposure conditions in the lab, that the material can stand the test of time and meet the objectives of 100-year long service life of bridge construction. But the testing procedures are not fully understood in terms of sensitivity and relevance to the true field performance of UHPC, so this is a field of ongoing research. Some of the required tests are challenging to conduct or require special expertise and testing facilities. As the official introduction of UHPC in the Code Standard is very new, it is challenging to find organizations that have the resources needed to conduct and assess the accuracy and relevance of the entire collection of prescribed mechanical and durability tests. The research challenge targeted by the PI is to proof test and if necessary, fine-tune, through calibration with DURA-UHPC, the draft testing procedures for UHPC materials that are about to be introduced in the Code. The research will meet the objectives of both partners, and will provide insights for optimizing the material and testing protocols.