Bond characteristics between low strength concrete and plain round bar under reversal loadings

Abstract

In order to evaluate the seismic performance of the existing RC buildings, pull-out tests were performed to obtain bond characteristics between low strength concrete and plain round bar under reversal loadings. From the test results of the specimen without repair, it is pointed out that the maximum bond stresses were less than the allowable stress for long term load, in addition that the degradations of bond stress were apparently influenced by the loading cycles. The specimens repaired with epoxy resin injection showed a significant increase of the bond stress. The analytical bond-slip hysteresis rule was derived from the test results. Comparisons between the observed hysteresis loops and the analytical ones were performed.