Experimental Study On The Behavior Of Steel Sleeve Splicing Grouted By RPC

Compared with cast-in-place buildings,prefabricated buildings have the advantages on saving resources and energy,reducing environmental pollution,improving labor productivity and project quality,which can promote realization of building industrialization.In the prefabricated concrete building,the reliable connection between prefabricated components is the key technology,the focus of which is the rebar connection.After a great deal of research,people gradually realized the advantages of the sleeve grouting splicing in power transmission mechanism and assembly construction.With the funds support of National Key Research and Development Program Project of China(2017YFC0703008),the grouting sleeve with the bonding medium of RPC(Reactive Powder Concrete)was studied by means of test analysis and finite element analysis.This paper mainly completed the following work.(1)7 kinds of RPC grout,with different water-blinder ratio,amount of expanding agent and steel fiber,were tested for obtaining their fluidity,vertical expansivity,compressive and rupture strengths.Besides,the pullout tests were carried on sleeve splicing specimens grouted by 5 kinds of the tested RPC,so that the interfacial bond strength of the deformed steel rebar in the RPC could be determined.Considering the requirement of work performance and interfacial bond strength,a non-steel fiber RPC grout,with expansion rate not less than 0.2 ‰ and compressive strength about 100 MPa,is recommended for the sleeve splice.(2)36 grouting sleeve specimens with RPC were tensioned under static test.The results show that(a)two categories of failure pattern including pullout and fracture of a bar,which occurred in the thread or the middle of the bar,may happen;(b)the longer the anchorage,the higher the carrying capacity of the grout sleeve splicing,however the lower the average bond strength;(c)when the bar pulls out from the sleeve,the rebar deviation will effect the average bond strength of specimens adversely;(d)the bond strength increases with the increase of the cover.On the base of the fact,we summarize the formula of the bond strength and obtain the critical anchorage length of bars in different diameters,which can be referenced in grouted sleeve splice desigh with RPC as bonding medium.(3)The mechanical and deformation behavior of t he grouting sleeve was analyzed by finite element numerical simulation based on ABAQUS.This paper has established finite element model of grouting sleeve with three anchorage length,the stress distribution of the outer surface of the sleeve and the bond-slip curve is analyzed.The results show that the numerical simulation results are in good agreement with the test results,which proves that the finite element model can better represent the mechanical properties of the grouting sleeve.At the end of this paper,the development and further promotion of RPC sleeve grouting are suggested.