Experimental Study On Bond Between Rubber Concrete And Normal Concrete

Rubber Concrete,also known as Elastic Concrete,is a new type of composite material formed by the incorporation of rubber particles of different sizes(mainly from waste tires)in ordinary concrete.In order to study the effects of different rubber particle size and different rubber content and composite modified rubber on the bonding properties of rubber concrete and ordinary concrete(RC-OC)in different interfacial types,and promote the application of RC in engineering.In this paper,two kinds of rubber particles with particle size of 1~3mm and 3~6mm,rubber content of 5%,10%,15%,20%,30%,unmodified rubber and composite modified rubber in no interfacical agent,cement paste interfacical agent,epoxy interfacical agent was studied,the main contents and conclusion are as follows:1.Through the compressive and splitting tensile experiments on 126 cube specimens with size of 150mm×150mm×l50mm,the effects of rubber particle size,rubber content and composite modified rubber on compressive strength and splitting tensile strength of RC were studied.The results showed that: the relationship between the rubber particle size and the compressive strength and splitting tensile strength of rubber concrete was more complicated,and the strength of big rubber particles was not always high;with the increase of rubber content,the compressive and splitting tensile strength of rubber concrete showed a decreasing trend;the reduction rule of compressive and splitting tensile strength of composite modified rubber concrete was consistent with that of unmodified rubber concrete,that was with the increase in rubber content gradually the strength decreased,and the composite modified rubber concrete strength had a certain improvement.2.Through the adhesive splitting tensile experiments on 189 cube RC-OC specimens with size of 150mm×150mm×l50mm and adhesive slant shear test on 189 prism RC-OC specimens with size of 100mm×100mm×300mm,the effects of rubber particle size,rubber content,interfacial agent type and composite modified rubber on adhesive splitting tensile strength and adhesive slant shear strength of RC-OC were studied.The results showed that: there is a consistent conclusion between adhesive splitting tensile strength and adhesive slant shear strength of RC-OC.Three kinds of interfacial agent types of RC-OC specimen was damaged along the bonding surface when it is subjected to tensile failure or compressive shear failure.(1)The relationship between the rubber particle size and the adhesive splitting tensile strength or adhesive slant shear strength of RC-OC was more complicated,which varies with the rubber content and the type of interfacial agent;(2)In general,with the increase of the rubber content,the adhesive splitting tensile strength of RC-OC showed a tendency to rise first and then decrease,and adhesive slant shear strength of RC-OC was gradually decreased;(3)all of the three kinds of interfacial agent types,the adhesive splitting tensile strength of RC-OC was smaller than that of new concrete,and the same kind of rubber particle size,the adhesive splitting tensile strength or adhesive slant shear strength was the largest when it was brushing epoxy interfacial agent,brushing cement paste interfacial agent and non-brushing interfacial agent the adhesive splitting tensile strength had no big difference to the adhesive splitting tensile strength,but to the adhesive slant shear strength brushing cement paste interfacial agent was bigger than non-brushing interfacial agent;(4)in general,the reduction rule of adhesive splitting tensile strength and adhesive slant shear strength of composite modified RC-OC was consistent with that of unmodified RC-OC and the former had a certain increase than the latter;(5)through the significance analysis of each influencing factors,rubber content and interfacial agent type had a significant effect on both adhesive splitting tensile strength and adhesive slant shear strength,rubber particle size and the composite modified rubber had no significant effect on both adhesive splitting tensile strength and adhesive slant shear strength.3.Through the SEM micrographs of the bonded specimen sections when the incorporation of 1~3 mm rubber particles were 10% and 20%,hydrated crystals of strong effect layer developed well and its structure was dense when brushing cement paste interfacial agent,in the 10% rubber content there was a gap while in the 20% rubber content there was no obvious gap,this is due to the presence of rubber particles,which absorbs a portion of the strain energy generated by the shrinkage;when the epoxy interface agent was applied,the infiltration layer and the strong effect layer were well developed,and the strong effect layer and the infiltration layer were closely connected,and the bonding effect between new RC and old OC adhesive interface was good.