Macro/micro characteristics variation of ultra-high performance fibre reinforced concrete (UHPFRC) subjected to critical marine environments

•The durability of UHPC servicing in critical marine environments is studied.•The effect of high temperature sea water on UHPC is tested.•The effect of steel fibre network on UHPC durability is evaluated.•Detailed mechanism on irons attacking effect on UHPC is clarified.•The approach to produce an advanced UHPC with good durability is shown.