Durability protection of the functionally graded structure concrete in the splash zone

Two kinds of single-layer concrete specimens and functionally gradient structure concrete with three different surface-layer thicknesses were prepared for conducting the rapid chloride ion penetration test and accelerated steel bar corrosion test. Obtained results showed that the durability of concrete structures in the splash is seen to increase in the following order, OPC single-layer system < FGC system < MIF single-layer system. Furthermore, in FGC system, increasing surface-layer thicknesses will improve its durability, and when its surface-layer reaches a certain thickness, its enhancement level is close to that of the MIF single-layer system. The functionally gradient structure concrete design is an effective way to reduce material cost without a significant reduction on ability to resist chloride eroside. But if the steel bar is arranged in the adhesive-bonded joint between two layers in FGC system, the corrosion will be more serious due of their differences of electrochemical property and permeability between two materials.

► FGC put forward for strengthening surface-layer of the concrete and enhance the durability of marine concrete structure.
► In FGC system, increasing surface-layer thicknesses will improve concrete structure durability.
► FGCs durability close to single-layer system prepared surface-layer materials if surface-layer reaches a certain thickness.
► If steel bar is arranged in adhesive-bonded joint between two layers in FGC system, the corrosion will be more serious.
► FGC design is an effective way to reduce material cost without a significant reduction on concrete structure durability.