Experimental Study On Mechanical Properties Of CC+CFRP Strip Reinforced Concrete Short Columns

CFRP(Carbon Fiber Reinforced Polymer)has become a new favorite in the reinforcement industry due to its advantages of high strength and efficiency,no increase in structural deadweight and size.At present,the overall package is mainly used in the structural reinforcement of CFRP.When the package of CFRP strips is enough to meet the engineering needs,the overall package will lead to the waste of CFRP materials,so the package of CFRP strips will be more economical and effective.When strip wrapping is used,the durability of the structure will be reduced due to the exposure of concrete.CC(Concrete Canvas)strong maneuverability can directly like cloth covering the surface of an object in various shapes,so used to repair scrambling,slope protection,pipeline protection and rapid paving and other military and civil engineering field,CC paste in Concrete structure surface,can repair and protection structure in service,and can be used as a new shell to protect the internal Concrete structure,it is worth to study further the application and popularization.In this paper,CC is placed between concrete and CFRP strips to be used in the strengthening of concrete structures.The axial compressive properties of CC+CFRP strips are studied.The influences of strip width(50 mm,75 mm,100 mm),strip spacing(50 mm,75 mm,100 mm)and core concrete strength grade(C20,C30,C40)on the axial compressive properties of CC+CFRP reinforced concrete short columns were studied by axial compressive tests.The research results show that the joint about CC + CFRP strengthening can improve the bearing capacity and deformation capacity of the specimens,when the strip width and strip spacing is 75 mm and 50 mm respectively,the specimen of performance overall optimal and CC + CFRP strengthening specimens were similar,in the same bearing capacity and deformation capacity under the condition of constraints can give priority to CC + CFRP strip form;When the strip width is large,the change of strip spacing has less influence on the bearing capacity;when the strip width is large,the change of stripwidth has greater influence on the bearing capacity.With the increase of the number of cladding layers,the bearing capacity first increases and then decreases.When the band spacing is large,there will be a weak constraint state.Increasing the band width can change the constraint state of the specimen,making the specimen change from the weak constraint state to the strong constraint state.With the increase of concrete strength grade,the binding effect of CC+CFRP band confined concrete decreases gradually.The ductility of CC+CFRP strips is better than that of CFRP strips alone.Finally,based on bilinear interpolation method,the bearing capacity and ductility of specimens with different strip widnesses and strip spacing were predicted,and the theoretical strength model of each CC+CFRP strip joint reinforced column was established.The comparison showed that the theoretical value was in good agreement with the experimental value,which proved the rationality of the model.