薄壁UHPC模壳-混凝土界面抗剪性能试验研究OA

To address the issue of collaborative performance failure caused by insufficient bond strength at the Ultra-High Performance Concrete(UHPC)-Normal Concrete(NC)interface in prefabricated mold shell systems,this study investigates 20 mm-thick UHPC mold shells.Double-sided direct shear push-out tests were conducted to explore the average ultimate load,load-slip curves,and interfacial shear strength of specimens subjected to different interfacial treatment techniques.The shear mechanisms of these techniques were analyzed,and a segmented bond-slip constitutive model was established based on the experimental data.The results indicate that:In the scouring treatment,a high-pressure water jet(pressure:25 MPa,jet angle:30°,duration:9-10 h)was used to achieve a surface roughness of(1.5±0.2)mm,the interfacial shear strength is significantly enhanced to 1.35 MPa through the synergistic effects of interface roughening and steel fiber anchoring.For the grooving treatment,the optimal parameter combination is a groove density of=1.25(groove width:20 mm,depth:5 mm,spacing:55 mm),achieving a maximum interfacial shear strength of 1.60 MPa.For the interface agent treatment,the optimal parameters involve adding cellulose ether(mass content:0.1%-0.2%)to cement paste and applying it with a coating thickness of 2.0-3.0 mm,resulting in a maximum interfacial shear strength of 1.95 MPa.A comprehensive comparison of the experimental results from different interface treatment techniques shows the following ranking of interfacial shear performance:XWSM-0.2%>KC-5/5>CM>GH.The cellulose ether interface agent(XWSM-0.2%)demonstrates significantly superior overall performance compared to traditional mechanical enhancement techniques due to its low dosage and high efficiency.