The direct method of fiber-optic sensor technique of steel corrosion in concrete structures

such as the principle

parameters and characteristics of various methods

is summarized.Some improving thoughts are proposed.It is well known that for steel corrosion in civil engineering environment is complex and monitoring time is long.For a monitoring method

in order to be practical in civil engineering

monitoring environment must reflect the real one

while precision and durability must be guaranteed in the sensor design as well as the measuring range of corrosion rate should be enlarged to the greatest extent.