Factors Affecting the Corrosion Rate at Intersection Points of Steel Rebar Mat in Reinforced Concrete Structures

摘要

This paper investigates high corrosion observed at intersections of steel rebars in the mat as comparedto low corrosion in all other areas observed in a typical reinforced concrete structure at multi-scale frommacro to micro level. This is a rather new and unusual finding having limited research in the past andneeded further investigation to clarify the mechanisms involved therein. Therefore, chloridecontaminated reinforced concrete slabs were cast and laboratory controlled experiments wereconducted for half-cell potential, corrosion current, concrete resistivity, SEM and MIP measurement.The experimental measurements at the intersection of steel bars were found to be actually much higherthan the areas in between them. This high corrosion rate at the steel bars intersections observed in thefield in an actual RC structure and verified by experimental measurements in this paper was furtherinvestigated to document the effect of variation in rebar spacing, connection type as well as the bindingwire material. This research is expected to result in improved steel rebar fixing and placementmethods in the future for all reinforced concrete structures. This research will result in establishedknowledge and material engineering behavior of high corrosion rate at the intersection points in steelmat of reinforced concrete. This research will enable future advances and trends in understanding theeffect of steel bar overlapping on the corrosion rate at the microstructure level of reinforced concreteengineering material as well as clarification of the phenomenon involved therein. As a scope for futureresearch, the experiment results presented in this paper can be utilized in the future for the effectiverole of reinforcement steel arrangement in the mat to improve the corrosion resistance and protection ofconcrete in civil engineering industry.