Revealing anti-corrosion behavior of magnesium alloy in simulated concrete pore solution

Abstract

A new concept of energy-saving design is proposed in this study that magnesium alloys are considered for rebars in concretes due to their lightweight, energy-efficient and environmentally friendly characteristics. Although magnesium alloys have promising physical properties such as high specific-strength and good fracture toughness, their poor corrosion resistance always hampers their wider applications. Therefore, it is urgent to conduct a preliminary corrosion evaluation. In this study, it is found by long-term immersion test and electrochemical corrosion test that AZ80 alloy has an excellent corrosion resistance in simulated concrete pore solution made of saturated Ca(OH)2 solution. Furthermore, the saturated solution is diluted by pure water and 3.5 wt% NaCl solution, respectively. The unsaturated solution diluted by pure water does not change the anti-corrosion behavior of AZ80 alloy, whereas the corrosion resistance is significantly deteriorated when chloride ions are introduced. SEM observation corroborates that there exists a layer of protective film on the surface after immersion in the simulated concrete pore solution for 30 days and an intervention of chloride ions can induce a catastrophic surface damage.