Experimental Study On Shear Bond Between Self Compacting Concrete And Old Concrete Z Specimen

Self-compacting concrete as a new concrete has the characteristics of autonomous mobile,self-filling,and its application in the enlarged cross section method is irreplaceable by other concrete advantages,especially the vibrating is particularly difficult,reinforced with situation.Enlarged cross section method to reinforce RC beam bridge is often caused by new and old concrete bonding interface bonding effect problem interface shear resistance is too small to reinforcement effect is poor,so the new and old concrete interface bonding shear function determines the enlarged cross section method could successfully.Binding to cut hair,cutting,planting bar,besmear brushs interface agent can improve self-compacting concrete and old concrete bonding surface shear capacity.And enlarged cross section method to reinforce way can be decomposed into top surface strengthening,side,bottom three different reinforcement reinforcement is obtained form,so the three different azimuth of reinforcing effect on the bonding surface shear is particularly important to improve the weaker reinforcement way bonding surface treatment can improve the overall shear effect.The 73 group consists of 219 blocks of Z type specimens using jack loading device direct shear tests of self compacting concrete and old concrete interface shear capacity,under the condition of considering the construction environment simulation side top surface strengthening,strengthening,bottom three joint bearing reinforcement is obtained,take on ordinary concrete carbonization to reflect the old concrete effects of aging on old concrete interface,chiseling,grooving,bar,interface agent four ways to deal with the effects of combination of shear strength,and four with the same density of different shapes of notched specimen groove type,through to self compacting concrete for concrete,new old concrete for ordinary concrete and old concrete surface with capacity of shear,and the bonding surface on stress-strain curve after that:(1)Bonding surface is the most vulnerable position Z type concrete specimen,specimen damage all starting from the position;Top,side,bottom reinforcement reinforcement is obtained on old concrete under three kinds of reinforcement bearing iron brush after the label with new concrete slurry shear strength better than just cut hair when shear strength;Top,side,bottom reinforcement reinforcement is obtained under three kinds of bearing of old concrete after grooving reinforce the bonding shear strength is stronger than carved brush slurry,reinforce the bonding shear strength;After planting bar on old concrete bonding interface,new and old concrete bonding shear strength was larger,the shear strength is superior to cut hair,cutting groove sample;(2)The top surface of the reinforcement effect was significantly higher than that of the side effect of strengthening the bottom reinforcement effect than side reinforcement effect;new concrete’s strength in a certain extent of new and old concrete shear strength of contact surface,the same old concrete strength,improve concrete grade can improve the shear capacity for cutting test;one,the main factors affecting the bonding strength of the cutting groove density,has nothing to do with the groove shape;the shear strength than the carbonation of concrete strength reinforcement concrete carbonation.(3)Through various specimens of maximum shear stress to propose three kinds of reinforcement bonding limit under the form of the shear stress formula,obtained by interfacial deformation and failure model of stress-strain test curve and test on the bonding phenomenon.The research conclusions of this paper can provide scientific basis for the reinforcement of RC beam bridge with the method of increasing the section of self compacting concrete.