Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Electrochemical activation of oxidation of sulfide-bearing aggregates in concrete specimens
Abstract There are several cases worldwide wherein sulfide-bearing aggregates in concrete elements/structures have undergone oxidation and caused extensive damage. Signs of observed deterioration include map cracking, pop-outs, and secondary products that were generated from swelling. Unfortunately, it takes years to detect these signs visibly. Thus, in this study, a new methodology is proposed to activate and accelerate the potential oxidation reaction of iron sulfide minerals in concrete aggregates using chloride ions as activators or catalysts for the oxidation reaction. To promote the rapid penetration of chloride ions through concrete specimens, an electrochemical treatment is proposed consisting of two main phases, namely chloride impregnation in the specimen and impressed voltage treatment. Concrete specimens each 100 mm in diameter and 200 mm in length were made using aggregates with or without iron sulfide minerals and a mix design resembling the one used for building house foundations in the Trois-Rivières case, Canada. The results showed that chloride ions could activate the reaction and act as catalysts for the oxidation reaction of sulfide-bearing aggregates under a constant current (impressed voltage). Finally, traces of iron oxides/hydroxides and the formation of secondary sulfates (i.e., gypsum and ettringite) were observed in the concrete made with sulfide-bearing aggregates. This new procedure is promising for evaluating the oxidation potential of concrete with sulfide-bearing aggregates over a reasonable testing period.
Electrochemical activation of oxidation of sulfide-bearing aggregates in concrete specimens
Abstract There are several cases worldwide wherein sulfide-bearing aggregates in concrete elements/structures have undergone oxidation and caused extensive damage. Signs of observed deterioration include map cracking, pop-outs, and secondary products that were generated from swelling. Unfortunately, it takes years to detect these signs visibly. Thus, in this study, a new methodology is proposed to activate and accelerate the potential oxidation reaction of iron sulfide minerals in concrete aggregates using chloride ions as activators or catalysts for the oxidation reaction. To promote the rapid penetration of chloride ions through concrete specimens, an electrochemical treatment is proposed consisting of two main phases, namely chloride impregnation in the specimen and impressed voltage treatment. Concrete specimens each 100 mm in diameter and 200 mm in length were made using aggregates with or without iron sulfide minerals and a mix design resembling the one used for building house foundations in the Trois-Rivières case, Canada. The results showed that chloride ions could activate the reaction and act as catalysts for the oxidation reaction of sulfide-bearing aggregates under a constant current (impressed voltage). Finally, traces of iron oxides/hydroxides and the formation of secondary sulfates (i.e., gypsum and ettringite) were observed in the concrete made with sulfide-bearing aggregates. This new procedure is promising for evaluating the oxidation potential of concrete with sulfide-bearing aggregates over a reasonable testing period.
Electrochemical activation of oxidation of sulfide-bearing aggregates in concrete specimens
Castillo Araiza, R. (Autor:in) / Fournier, B. (Autor:in) / Duchesne, J. (Autor:in) / Rodrigues, A. (Autor:in)
23.04.2023
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch