Definition - What does Shotcrete mean?
Shotcrete refers to a type of concrete that is applied by spraying it through a hose at high velocity to a surface containing rods, mesh or other structural reinforcements. The most significant cause of concrete deterioration is the corrosion of reinforcing steel (rebar) used prior to shotcrete applications.
Corrosionpedia explains Shotcrete
Generally, embedded galvanic anodes are used in rods, beams and other metallic reinforcement structures used to increase the durability of shotcrete applications.
The corrosion of reinforced shotcrete structures such as bridges is often caused by the infiltration of chlorides. When enough chloride comes into contact with the reinforcing steel, the protection afforded to the steel breaks down and corrosion begins. As a corrosion by-product, iron oxide occupies a larger volume than the steel or other metal. This negatively increases internal tensile stresses, which cause steel expansion, cracking and patch accelerated corrosion where certain areas of a structure are fixed or upgraded prior to others.