Steel fibre content and interconnection induced electrochemical corrosion of Ultra-High Performance Fibre Reinforced Concrete (UHPFRC)

This study addresses the steel fibre content and interconnection induced electrochemical corrosion of Ultra-High Performance Fibre reinforced Concrete (UHPFRC) subjected to critical marine environment. The design basis of UHPFRC matrix is particle close packing principle, and then its fresh and hardened properties are investigated. After that, the AC-impedance spectroscopy is used to measure the electrical resistivity of the developed UHPFRC with different fibre amount. Furthermore, to clarify the distribution and interconnection of fibres in the hardened UHPFRC, an X-ray CT is employed. The obtained results show that with an increase of the added fibres amount, the rapid chloride migration (DRCM) and the electrical resistivity of the designed UHPFRC simultaneously decrease. When the added steel fibres amount reach 2% (vol.), a sharply decrease of the electrical resistivity can be observed, which implies that a steel fibre network formation could be obtained in the hardened UHPFRC.