| Title |
Properties and Prediction Model for Ultra High Performance Fiber Reinforced Concrete (UHPFRC): (II) Evaluation of Restrained Shrinkage Characteristics and Prediction of Degree of Restraint |
| Authors |
류두열(Yoo, Doo-Yeol) ; 박정준(Park, Jung-Jun) ; 김성욱(Kim, Sung-Wook) ; 윤영수(Yoon, Young-Soo) |
| DOI |
https://doi.org/10.12652/Ksce.2012.32.5A.317 |
| Keywords |
초고성능 섬유보강 콘크리트;수축;링-테스트;응력 이완;구속도 ultra high performance fiber reinforced concrete;shrinkage;ring-test;stress relaxation;degree of restraint |
| Abstract |
In this study, to evaluate the shrinkage behavior of ultra high performance fiber reinforced concrete (UHPFRC) under restrained condition, restrained shrinkage test was performed according to ring-test mostly used at home and abroad. Ring-test was performed with the various thicknesses and radii of inner steel ring to give different degree of restraint. Free shrinkage and tensile tests were carried out simultaneously to estimate the degree of restraint, stress relaxation, and shrinkage cracking potential. Test results indicated that the average steel strain and residual tensile stress were reduced as the thicker inner steel ring was used, whereas degree of restraint was increased. The steel strain, residual tensile stress and degree of restraint were hardly affected by the size of radius of inner ring. In the case of all ring specimens, shrinkage crack did not occur because the residual tensile stress was lower than the tensile strength. About 39~65% of the elastic shrinkage stress was relaxed by the sustained interface pressure, and the maximum relaxed stress was increased as the thicker inner ring was applied. Finally, the degree of restraint with age was predicted by performing non-linear regression analysis, and it was in good agreement with the test results. |