비정질 강섬유보강콘크리트의 구속건조수축균열 특성

Abstract

In this study, free and restraint drying shrinkage tests of conventional and amorphous steel fiber-reinforced concrete were performed to investigate the shrinkage characteristics. To consider the effect of restraint condition of concrete on shrinkage cracking, three different test setups were used: ring type restraint test according to ASTM C 1581-04, dumbbell type restraint test according to KS F 2595, and modified dumbbell type restraint test with notches. Crack widths and strain profiles acquired from the tests were compared and investigated. The test results showed that the addition of amorphous steel fibers with 0.2-0.4% volume fraction into concrete resulted in 30% reduction of free drying shrinkage, 3-5 days delay of crack development time, and 20-60% reduction of crack width. Thus, it can be concluded that the amorphous steel fibers can be used for the purpose of crack control of concrete shrinkage cracking.