Multifunctional corrosion control system as a sustainable approach for reinforced concrete elements

Corrosion inhibitors can be utilized to decrease the corrosion kinetics and therefore increase the durability of reinforced concrete structures. Recently, a green synthesized organic compound, 1-benzyl-4-phenyl-1H-1,2,3-triazole (BPT), was shown to be a successful green organic corrosion inhibitor for mild steel. Studies suggested that the BPT adsorbs chemically onto the steel and acts as a mixed inhibitor, suppressing both the anodic and cathodic corrosion kinetics of steel. In addition, microcapsules have shown to be an efficient way for a controlled inhibitor release in reinforced concrete structures. On the other hand, geopolymers (GPs) comprised of a long range of covalently bonded alumino-silicates, with amorphous network structure are generally considered as a suitable substitute for OPC for many structural applications due to their high strength and durability. The use of recycled waste materials or natural abundant materials for the production of GPs has attracted world-wide attention as it presents an environment-friendly aspect that may shed light on for replacing traditional OPC by its sustainability. One of the advantages of GPs is the significant reduction to CO2 emission due to the energy consumption, the geopolymers utilize materials such as fly-ash, which is a byproduct of coal combustion, or natural precursor materials (clays, basalt rocks, etc.) and their derives (metakaolin), which does not produce net CO2 emission. Recent studies have shown that GPs based cements can hinder the corrosion of reinforcement steel in concrete structures when compared to OPC, mostly because of lower chloride ingress (due to barrier protective capabilities) and the highly alkaline pH nature of geopolymer cements.