The effect of chloride ingress in reinforced geopolymer concrete exposed in the marine environment

Determining the durability of geopolymer materials in a real field environment is important to enhance the feasibility of their use in concrete production. This paper investigates the durability of slag-based geopolymer concrete (SGPC-M) exposed in the spray/splash zone of the marine environment. Properties of SGPC-M in the marine environment including chloride resistance, absorption characteristics, and the scaling effect were examined and compared with ordinary Portland Cement concrete (OPC-M) properties in the same environment. The test results indicate that the SGPC-M has a lower resistance to chloride penetration than the OPC- M concrete. Compared to the OPC-M, higher values of diffusion coefficient and lower values of chloride binding capacity were obtained for the SGPC-M concrete. Besides, the study on the pore characteristics and absorption behaviour of the concrete indicates that the SGPC-M possesses more pores than the OPC-M, which is related to the lower resistance to chloride penetration in the marine environment. Furthermore, the microstructural changes due to chloride attack in the SGPC-M are different than the changes in the OPC-M concrete, which was identified from the SEM and XRD analysis.