Assessing Suitability of Geopolymer Composites Under Chloride Exposure

Abstract

AbstractChloride ingress is primarily responsible for initiating corrosion of the embedded reinforcement within concrete, especially in marine zones where reinforced concrete structures are often exposed to harsh chloride environment. Thus, it is often deemed essential to assess concrete resistance against chloride penetration. However, such deterioration of geopolymer concrete structures instigated by chloride exposure, has had inadequate examination. This study investigated the performance of developed fiber reinforced geopolymer composites against ingress of chloride ions. The mixes have been prepared by incorporating combination of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) as source materials, powder-based alkaline activators and Poly-Vinyl Alcohol (PVA) fiber under ambient curing. The chloride resistance of the developed mixes was measured through Rapid Chloride Permeability Test (RCPT). Additional transport properties such as water absorption, surface resistivity and sorptivity along with mechanical properties in terms of compressive strength and ultrasonic pulse velocity (UPV) had also been evaluated. The study showed suitability of high calcium FA and GGBFS over low calcium FA based geopolymer composites for applications where chloride-related durability is concerned. Based on the observed transport property values, the influence of source material and activator variation was assessed to evaluate an optimum and suitable mix combinations to address chloride-related durability concerns. The mixes with high calcium were observed to produce denser matrix showing prospect against chloride permeability. This paper aims to provide with a base guideline to assist engineers in designing a durable geopolymer composite when exposed to chloride environments.KeywordsGeopolymersCorrosionDurabilityChloride-related durabilityChloride penetration resistanceRapid chloride permeability test (RCPT)