A novel corrosion resistant repair technique for existing reinforced concrete (RC) elements using polyvinyl alcohol fibre reinforced geopolymer concrete (PVAFRGC)

Strain hardening fibre reinforced geopolymer concrete, which utilises waste material rather than primary mineral products and is suitable for cast-in-place applications, shows considerable potential as a resistant, more environmentally friendly, concrete repair material. This study assesses the corrosion protection performance of polyvinyl alcohol fibre reinforced geopolymer concrete as a repair material. The applicability of polyvinyl alcohol fibre reinforced geopolymer concrete as a repair material for preventing steel corrosion was investigated using specimens that simulated surface coating repair. Large scale beam repair was conducted using beams where part of the concrete cover at various depths (12.5% and 25% of the total beam depth) was replaced by polyvinyl alcohol fibre reinforced geopolymer concrete. Accelerated corrosion tests were performed using an induced current technique by applying a nominal 300 mA/cm2 constant anodic current for approximately 90 days. Results from flexural strength tests showed significant improvements in the structural performance of the reinforced concrete beams repaired with polyvinyl alcohol fibre reinforced geopolymer concrete following accelerated corrosion. The results can be summarised as follows: surface coating with polyvinyl alcohol fibre reinforced geopolymer concrete significantly reduced corrosion damage in terms of mass loss, crack distributions and structural performance, while differences in surface coating thickness also considerably affected the corrosion resistance of the repaired beams.