Investigation of bond stress changes due to rebar corrosion in geopolymer concrete containing leca lightweight aggregates

In the construction industry, concrete has always been recognized as one of the most widely used and effective materials. Considering the environmental challenges and problems associated with the production of cement used in conventional concrete, many researchers today have shown interest in producing and studying cement-free concretes. One of the green concretes that has recently gained attention is geopolymer concrete. In this laboratory study, the physical and mechanical properties of slag-based geopolymer concrete activated by alkaline activators were examined. Given the presence of reinforcement networks to improve tensile strength, investigating the variations in bond stress between concrete and steel rebar in geopolymer concrete is one of the key parameters. To assess this, concrete samples containing steel reinforcement were produced and subjected to accelerated corrosion. Through rebar pull-out tests and equations related to bond stress, the bond stress values were obtained and analyzed for three types of concrete cover and two types of concrete with different strength grades, which differed in the coarse aggregates used. Since corrosion occurs through moisture penetration into concrete, one set of samples used lightweight geopolymer concrete with expanded clay aggregates (LECA) to observe the impact of permeability. The results of the experiments showed lower bond stress in lightweight concrete due to its lower compressive strength. However, the variation and reduction in bond stress with increasing corrosion age were less significant in the LECA-containing samples due to their lower permeability.

کلیدواژه ها:

Geopolymer concrete ، green concrete ، Leca ، bond stress ، rebar corrosion