后浇普通混凝土与预制UHPC的黏结受剪性能研究

In order to study the bond behavior between precast ultra-high performance concrete (UHPC) and post-cast normal concrete (NC), taking the slotting density and the strength of the post-cast normal concrete as variables, double-sided shear test of 12 groups of UHPC-NC composite specimens and four groups of new-old C40 composite specimens were conducted. The results show that the mechanical interaction of the bonding interface with precast UHPC slotting is much greater than the shear strength of the post-cast NC. Thus, the shear failure of the post-cast NC along the bonding interface is observed. Under the same slotting density, the bond shear strength of UHPC-NC is higher than that of new-old C40 concrete by 19.63%-48.15%. When the strength of the post-cast NC is the same, the greater the slotting density, the higher the shear strength at the bonding interfaces. When slotting densities of precast UHPC are 1.33, 2.67, and 4, the shear strengths of single slotting are 1.398, 1.226, and 1.044 MPa respectively. Slotting density and post-cast NC strength have significant effects on the shear strength of UHPC-NC bonding interface. The effect of slotting density on UHPC-NC bonding shear strength is much greater than that of post-cast NC strength. Based on the test results, a calculation formula for the bonding shear strength of precast UHPC and post-cast NC with consideration of the influence of slotting density and strength of post-cast NC was proposed, the calculated results were in good agreement with test tesults.