Durability of ambient cured alumina silicate concrete based on slag/fly ash blends against sulfate environment

The durability of a concrete depends upon resistance against various properties like sulfate, chloride, and acid, corrosion environment. One of the important durability properties of the concrete is its resistance against sulfate environment. This research paper outcomes the results of an experimental investigation on durability of geopolymer concrete produced with GBFS (Granulated Blast Furnace Slag), Fly ash (Class F – Grade) and alkaline activators under ambient temperature, subjected to magnesium sulphate and sodium sulphate environment. GBFS was partially replaced by fly ash at various replacement levels from 0 to 50% with a constant concentration of 12 M alkaline activator solution. The main parameters of this study are evaluation of change in weight, strength, and micro structural changes. The techniques used to study the degradation a Scanning Electron Microscopy and X-ray Diffraction methods. Fourier transform infrared spectroscopy was also used as an additional method of study. Geopolymer concrete with GBFS under ambient curing shows better results when compared to geopolymer concrete with GBFS blended with fly ash. In the magnesium sulfate environment, the rate of reduction of strength of GPC with GBFS is 35%, while for 40% replacement of fly ash to GBFS performs well with a strength gain of 10%. Similar observations are also observed in sodium sulfate environment in which 40% replacement of fly ash to GBFS performs well. Therefore, it is concluded that partial replacement 40% of fly ash to GBFS is the appropriate level satisfying the durability properties for ambient cured geopolymer concrete.