Experimental Study On Bond Performance Between Carbonized Concrete And Deformed Bars Under Cyclic Loading

The carbonation of concrete can cause durability deterioration of reinforcedconcrete structures, which have important influence on carrying capacity and normalusing functions of structures. Reliable bonding between reinforced bar and concrete canensure the normal work of reinforced concrete structures, but carbonation change theperformance of concrete material itself, which is bound to affect the bond between steeland concrete. At present, although there are many studies on the bond propertiesbetween steel and concrete, there is little research on considering the influence ofconcrete carbonation on the bond performance. In addition, under cyclic loadings suchas earthquake, the dynamic response of reinforced concrete structure is highlydependent on the bond performance between steel and concrete. Therefore it is soimportant to study the bond performance between deformed bars and carbonizedconcrete under cyclic loadings both in theory and practical significance.In the first place, the test did a fast complete carbonation on the C20?C30?C40three different concrete strength specimens, and measure the non-carbonated andcarbonized standard cube specimens?tensile strength, after that, all of the bondedspecimens were carried out by steel pull-out test under monotonic and cyclic loading,then the bond stress vs. slip curves were obtained.Secondly, this thesis analysed the influence of carbonation on bond performancebetween concrete and deformed bars by compared with the bond stress vs. slip curves ofnon-carbonated and carbonized specimens. The research suggested that the carbonationof concrete can improve the compressive strength of the concrete itself, and thusimprove bond strength of the specimen?bond stiffness of the initial load and energy absorption capacity, and have some improvement in the bond deterioration under cyclicloading.Finally, on the basis of experimental data, this thesis created the constitutiverelationship of bond stress-slip between carbonized concrete and deformed steels undermonotonic and cyclic loadings.This thesis started from the changes of material performance of concrete itself,ignored the impact of steel corrosion after carbonation, and discussed the bondperformance between carbonized concrete and deformed bars under cyclic loadingthrough experimental study?which have important theoretical reference value for thefuture research on durability assessment and anti-seismic property of reinforcedconcrete structure.