喷射超高韧性水泥基复合材料与砖基底界面黏结性能的试验与理论研究OA

In order to investigate the interfacial bonding properties between sprayed ultra high toughness cementitious composite(UHTCC)and brick substrate,three key factors,namely spraying direction,brick type,and interface mortar type,were selected based on the characteristics of the spraying process,with bond splitting cracking strength and interfacial shear strength adopted as evaluation indices.The interfacial failure process and crack propagation patterns were observed and analyzed using digital image correlation(DIC)and computed tomography(CT).The experimental results indicate that spraying direction affects the interfacial bonding performance.Specifically,downward spraying provides the best bonding performance,with bond strengths 15.5％-22.0％higher than those achieved by upward spraying.Upward spraying produces the poorest bonding performance,while lateral spraying gives intermediate results.Brick type is the most dominant factor influencing the interfacial bond strength.Cement bricks exhibit the best bonding performance,with bond splitting cracking strength ranging from 1.04 to 1.49 MPa and interfacial shear strength ranging from 1.45 to 2.10 MPa.In contrast,autoclaved sand-lime bricks exhibit the poorest bonding performance,with bond splitting cracking strength only between 0.33 and 0.49 MPa and interfacial shear strength only between 0.32 and 0.62 MPa.Ordinary sintered bricks show intermediate bonding performance,with splitting cracking strength of 0.94 to 1.21 MPa and interfacial shear strength of 1.41 to 1.93 MPa.The type of interface mortar also has a considerable influence on the interfacial bonding performance.The use of epoxy mortar effectively enhances the bond strength,achieving an average improvement of 27.7％to 40.9％,while cement mortar provides only limited enhancement.Through range analysis and variance analysis,the influence degree of each factor on the interfacial bond strength was clarified,and multi-parameter coupling design formulas considering the effect functions of spraying direction,brick type,and interface mortar were established.