STUDY ON ULTIMATE BOND STRENGTH AND ANCHORAGE LENGTH OF THE REBAR IN THE RECYCLED AGGREGATE CONCRETE

According to the pull out test, this paper analyzed the influence factors which include the recycled aggregate replacement ratio, type of the rebar and strength grade of recycled concrete on ultimate bond strength and gave the formula to calculate the ultimate bond strength.Analysis shows that the calculated values agree well with the experimental results.The different research results for the influence of the recycled aggregate replacement ratio on the ultimate bond strength were analyzed comparatively, and the analysis shows that the recycled aggregate replacement ratio cannot be used as the only influence factor to analyze the influence on bond performance of the recycled aggregate and also need to consider the material performance of the recycled aggregate and the coupling effects between the recycled aggregate and the coarse aggregate.The increasing coefficient of ultimate bond strength was defined, and analysis shows that influence level of the rebar type is greatest, followed by diameter of the rebar, the influence level of the strength grade is least, and the ultimate bond strength of ordinary concrete is generally slightly larger than the recycled concrete when the recycled aggregate replacement rate is 100%.Finally, the suggested method which can determine the anchorage length was proposed.