Quality Evaluation of Granulated Blast Furnace Slag Sand Via Acid Immersion and Freeze-Thaw Tests

Abstract

In recent years, the use of granulated blast furnace slag (GBFS) sand as fine aggregate in concrete has been increasingly discussed from the viewpoint of environmental impact reduction and effective utilization of by-products in Japan. The various physical properties of concrete with GBFS sand, such as the compressive strength, drying shrinkage, and carbonation, were evaluated. Especially, it was demonstrated that GBFS sand can modify the hardened cement paste around it owing to the reaction of amorphous phase in the sand. Moreover, its resistance to sulfuric acid is considered to be as excellent as that of BFS powder. Therefore, in this study, we attempted to evaluate the performance of GBFS sand using a freeze-thaw (F-T) and acid immersion tests. Consequently, it was found that GBFS sand mortar had a significantly higher resistance to F-T and sulfuric acid than crushed sand mortar. In addition, it improved the resistance to freezing and thawing by prolonged curing. In our experiments, the resistance of GBFS sand mortar to sulfuric acid was measured to be approximately four times higher than that of crushed sand mortar. In contrast, in the case of nitric acid, the ratio was measured to be only two times higher. From the above results, it was concluded that the performance of GBFS sand can be easily judged by F-T and sulfuric acid immersion tests.

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