EXPERIMENTAL STUDY ON BOND PROPERTIES BETWEEN RUBBER CONCRETE AND REBARS IN THE FREEZE-THAW ENVIRONMENT

To understand the bond performances between concrete mixed with rubber and rebars in the freeze-thaw environment, rebars were slotted and then strain gauges were stuck crosswise on the groove surface, finaly, the rebars were closed and embedded in the rubber-concrete cubes. After being subjected to rapid freeze-thaw, the central pull-out tests were conducted to study the effect of rubber content and freeze-thaw cycles on load-slip curves, rebar strain in effective anchorage length and bond stress in effective length. The results showed that the bond-failure process could be divided into five stages:micro slip, internal crack slip, acceleration slip, slip stable development and slip softening. Under the action of freeze-thaw cycles, with the increase of pull-out loads, the strain of rebars at each point in the anchorage length with the different rubber content increased more evenly, which indicated that concrete mixed with rubber had good frost resistance. When the rubber content was not more than 10%, the change of bond performances between concrete and rebars in the freeze-thaw environment was small, and the peak slip reduced about 6% than that of ordinary concrete. With the increase of freeze-thaw cycles, the overall distribution of bond stress of concrete mixed with rubber was more uniform, and the load transfer capacity was good.