装配式NC板UHPC湿接缝轴拉性能试验研究

Experimental Study on Pulling Performance of UHPC Wet Seam in Assembled NC Plate

装配式混凝土结构因施工便捷、节约工期等优势被频繁应用,常规混凝土结构使用的湿接缝为普通混凝土(NC),但是NC湿接缝与原结构粘结强度不高,导致接缝处出现了大量的病害。而超高性能混凝土(UHPC)有着更小的级配作湿接缝时与原NC结构具有更好的粘结强度,但目前国内对装配式NC-UHPC湿接缝轴拉性能研究较少,故本试验设计NC和UHPC两种湿接缝共6个试件并结合有限元分析,来探讨其轴拉性能。经试验和有限元分析后得出结论:UHPC作湿接缝时装配式NC-UHPC结构的轴拉性能远优于NC湿接缝,试件的初裂及极限荷载均远超NC接缝,故可考虑UHPC作为湿接缝应用。

Assembled concrete structures are frequently applied due to their advantages of convenient construction and time saving. The existing wet joints used in conventional fabricated concrete structures are normal concrete(NC), but the bond strength between NC wet joints and old concrete is not such high. This leads to a large number of deficiencies at the joints of cast-in-place concrete. Ultra-high performance concrete(UHPC) has smaller gradation and can be used in wet joint, performing better bond strength with the original normal concrete. However, the study on the NC-UHPC structures under the axial tensile force is relatively rare in current China. Therefore, six specimens of NC and UHPC wet joints were designed in this experiment, and their axial tensile properties were discussed by combining the finite element analysis. After the axial pull test and the finite element analysis, it is concluded that the axial pull performance of the assembled NC-UHPC structure is much better than that of NC when UHPC is used as a wet joint. Generally, the initial cracking load and ultimate load of the members with UHPC joints are much better than NC joints. Therefore, UHPC can be used as a wet joint.