The strength and durability of steel fibre recycled concrete in chloride environments

The strength and durability of structures are strongly influenced by damage from steel corrosion caused by chloride ions. This chloride-induced corrosion mechanism is investigated yearly. However, the strength and durability of steel fibre recycled concrete (SFRC) in chloride environments have rarely been studied. By changing the water–cement ratio of SFRC blocks, the sodium chloride (NaCl) concentration of the soaking solution, soaking time and the number of chloride-ion-permeating surfaces, a series of compressive strength experiments were performed, where the chloride ion content of tested blocks was measured. The results showed that the water–cement ratio of blocks greatly influences the strength and durability of SFRC and that the sodium chloride concentration of the soak solution, and the number of chloride-ion-permeating surfaces, also affects the blocks to a certain degree. A water–cement ratio of 0·45 should be chosen due to its low chloride ion content and high compressive strength. The water–cement ratio and the number of chloride-ion-permeating surfaces can be controlled more easily in practical engineering, it is therefore necessary to optimise the best water–cement design ratio and add a water-repellent coating on the SFRC surfaces to ensure the durability of the structure.