Mechanical properties and durability of injected SCC panels by epoxy against freezing and thawing

Abstract

Repairing cracks in concrete structures exposed to freezing and thawing cycles by injecting epoxy resin and the main factors affecting it, such as epoxy viscosity, crack width, and the crack's moisture content, has been studied in a few research.This paper utilized commercial epoxy resins with high, medium, and low viscosities to inject through simulated cracks. In addition, repair methods were tested and evaluated by injecting epoxy resins in dry, damp, wet, and water-filled conditions. Furthermore, two crack widths (0.5 and 0.8 mm) were simulated on the specimens, and the effects of the repairing materials' thickness on the rehabilitation success were examined. The specimens’ durability with 24 cycles of freezing and thawing was investigated.Results demonstrate that water's presence in different situations, especially the water-filled ones in the interfacial zone, deteriorates the bond characteristics; Contrastly, the results were better in the wet situation. It can be concluded that injecting in the dry situation is optimized. The results showed that curing in lower temperatures takes longer than in higher temperatures. Moreover, a correlation was observed between the viscosity and its effect on tensile bond strength and actual shear strength in the slant shear test. It was found that the low-viscosity resin showed better performance than the high-viscosity resin overall. Moreover, the low-viscosity resin achieved 25% more shear strength in the slant shear test than the high-viscosity. In the freezing and thawing cycles, the injection was stable only in dry cracks, and in other moist conditions, the samples failed the freezing and thawing cycles.