Investigation of the durability of geopolymer concretes produced by using ferrochrome slag and blast furnace slag against to acid, salt and sulfate effects

In this study, durability of geopolymer concretes produced by using Elazığ ferrochrome slag (EFC) and blast furnace slag (YFC) as binder against to acid, salt and sulfate effects was investigated. For this purpose, 5 groups of geopolymer concretes were produced by adding 0%, 25%, 50%, 75% and 100% YFC by weight of instead of EFC. The produced geopolymer concrete samples were exposed to phosphoric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, sodium chloride, magnesium chloride, magnesium sulfate and sodium sulfate solutions with a concentration of 5% for 12 weeks after completing curing periods of 28 days. In this process, compressive strengths, ultrasonic pulse velocities (UPV), weight and length changes of geopolymer concretes were determined and their visual changes and microstructure analysis were examined. The test results were compared with the results of the control samples at the same age. Based on the results of experiment, the compressive strengths of geopolymer concretes were most affected by sulfuric acid followed by hydrofluoric acid, hydrochloric acid, phosphoric acid, sodium sulfate, magnesium sulfate, magnesium chloride and sodium chloride solutions. When the samples were examined visually, no deterioration is observed in the samples held in the salt and sulfate solutions, while in the acid solutions; the surface of the samples exposed to sulfuric acid, hydrofluoric acid and phosphoric acid solutions were formed the cracks and sample surfaces were deteriorated. The surface of samples exposed to the hydrochloric acid solution had no cracks but darkened in the color of the samples. KEYWORDS: Geopolymer concrete, Elazığ ferrochrome slag, blast furnace slag, acid effect, salt effect, sulfate effect