Bestandighetsstudie av Ultra-High Performance Concrete (UHPC) : En forskning om påvirkningen av rissvidde, overdekning og eksponeringsmiljø med hensyn på betongens beskyttelsesevne mot armeringskorrosjon

Abstract

Ultra-High Performance Concrete (UHPC) was developed in research to increase the strength and durability of concrete. The material has shown remarkable ductility, durabilityand strength properties in laboratory tests, but has not beenmuch tested in practice. This master thesis presents an experiment to investigate the durability of UHPC in two marine environments in view of the risk of rebar corrosion. Factors under consideration are cover depth and crack width to observe how this will influence the penetration of aggressive substances that can cause corrosion. To investigate the corrosion state and chloride content, electrochemical impedance spectroscopy (EIS) and Volhard ́s method were performed. This was done in orderto observe the permeability of UHPC.The results showthat the EIS measurements for the UHPC beams have significantly greater corrosion resistance compared to thestandard concretebeams,SV-40. UHPC has a resistance of almost tenfold of the SV-40. The result from the EIS-measurement for the corrosive rebar, makes a too weak comparison basis to draw a conclusion onwhether there is corrosion in the different exposure environment. Disregarding that there iscorrosion on the rebars, the UHPC beams could be dimensioned with a smaller concrete cover and a larger crack width compared with the requirements from the standards. Overall, this experiment shows that UHPC has a superior corrosion resistance in practice compared to SV-40.