Abstract

Existing RC Buildings have some cracks and the repairing service might last the buildings for long life. The durability of the RC component is evaluated by several ways as like as carbonation resistance test, permeability test, water penetration test, and so on. Therefore, it need to be measured how much advantage the concrete crack with repair have for the durability. The aim of this paper is to study on advantage of repairing a crack of concrete to the carbonation resistance and the waterabsorbing property by the experimental way. The specimens were prepared in the following point. The finishing (direct finishing and mortal tile finishing), crack width (0, 0.05, 0.5, and 2mm), and choice repairing or not. All concrete specimens were formed 10 x 10 x 20cm and those W/C were 0.55. Then, the specimens were tested by the accelerated carbonation. After 4, 8 and 26weeks accelerated carbonation, the carbonation depth and the carbonation shape of the concretes were measured by 1% phenolphthalein reaction. Also, the amount of absorbed water from the bottom were measured at 1, 3, 6, 24, 48, 72 and 168h. From the results, the carbonation went rapidly located in 2cm around the crack in the case of the no-repair specimens, regardless of any finishing. But in the case of the specimens repaired, it went evenly from the exposure side. And water absorbing test results show a trend that water amount of the concrete with a crack more increase than one of the no-crack concrete.