Abstract
Quality of surface layer of concrete structures greatly affects the durability of structures. Inspection system for surface layer concrete using non-destructive tests is strongly required. In this research, surface water absorption and surface air permeability were investigated. For real concrete structures, surface absorption and surface permeability tests were applied, and correlation between those two properties was investigated. Through this investigation, it was found that microcrack in the surface layer might adversely affect the resistances for surface absorption and for surface permeability. Therefore, in this study, the effects of microcrack on those resistances were investigated in column specimens. Regarding surface absorption, due to microcrack, the resistance for surface absorption was remarkably decreased, and silane type water repellents improved the resistance. In this research, the adverse effects of microcrack on water absorption were proved remarkable in the range of 1cm from the surface. Regarding surface permeability, due to microcrack and due to the existence of re-bars in the surface layer, measured resistance by surface permeability test tended to be smaller than the resistance measured in one dimensional air permeability test. When we try to establish inspection system for surface layer concrete, we should take care about the effects of microcrack in the surface layer.
