Experimental Research On The Interfacil Shear Behavior Of UHPC-NC Structure Under The Condition Of Normal Curing Temperature

Ultra High Performance Concrete(UHPC)is a new type of material in the field of civil engineering at present,UHPC is widely used for structure reinforcing in China by the advantage of its ultra high tensile and compressive mechanical properties.The high temperature steam curing of UHPC would make some influences on the duration of ordinary concrete,this paper studies the interfacil shear behavior of UHPC-NC structure under the condition of normal curing temperature,compared with the high temperature steam curing of UHPC-NC under the same conditions.In order to study the interfacial shear behavior,seven groups of UHPC-NC structure were designed and manufactured(each group of two).The interfaces were roughened(named as ZM-C50),roughened(named as ZMJ-C50),roughened(named as ZMP-C50),planted with steel bar(named as ZJ-C50),exposed reinforcing steel(named LJ-C50),grooved(named as QC-C50)or caved(named as ZD-C50)respectively,then a push-out experiment were launched on these groups.The paper carried the following research and get relevant conclusions:(1)A push-out test of seven groups of UHPC-C50 structure is carried out,full notes about the process information,data acquisition,key reactive parameters are made.Then we analyze the failure mechanism of the test and get the shear load-slip curves and load-stress curves of these test specimens,the test phenomenon shows that the weakest occurs near the interface under different processing interfaces.The shear slip component is basically under a millimeter after shear failure of UHPC-NC structure,the specimen can be seen as a whole load of structure before the interface breaks down.The shear slip component is basically above a millimeter after shear failure of LJ-C50,ZJ-C50,the ductility of specimen has been greatly improved.(2)The ductility and reliability of LJ-C50,ZJ-C50 have been greatly improved in these processes,the interface would not completely destroyed after a certain slippage,specimen is able to maintain high capacity in large fissures.(3)After the destruction of the specimen which were roughened and exposed reinforcing steel,the scope of ordinary concrete bonded on UHPC side is relatively large,on the contrary,the interface of the ductilities which were planted with steel bar and grooved are relatively flat.(4)Due to the analysis of ultimate load and sliding distance of UHPC-NC structure under different curing conditions,the interfacial shear capacity of ZM-C50,LJ-C50,QC-C50 under normal temperature curing is comparatively high,the result shows clearly that the adhesive strength made a good showing under normal temperature curing,specimen shows high integrity.