装配式车站构件与混杂纤维UHPC湿接缝界面的高温粘结性能研究

Study on High-Temperature Bonding Properties of Prefabricated Station Components and Hybrid Fiber UHPC Wet Joint Interface

UHPC对提升预制结构湿接缝的性能具有重要作用,但接缝界面在高温环境中有高温爆裂及性能下降的风险。本文研究了高温环境对钢纤维和聚丙烯纤维混掺的UHPC与预制混凝土界面粘结性能的影响。试验结果表明:在高温作用下,UHPC-混凝土界面在受热初期(100℃)的粘结强度得到小幅度的提升。随着温度的进一步升高,界面的粘结强度劣化。而高温作用对粘结性能的影响更显著。当受热温度为500℃时,体系的粘结强度损失可达30%~40%。综合UHPC湿接缝界面的抗高温爆裂性能和力学性能的高温退化,当钢纤维和聚丙烯纤维含量分别为2 wt%和0.5 wt%时,UHPC材料与预制混凝土界面具有较好的粘结性能。

UHPC plays a crucial role in enhancing the performance of wet joints in prefabricated structures, but there is a risk of high-temperature cracking and performance degradation in joints exposed to high-temperature environments. This study investigates the impact of high-temperature environments on the bonding properties of UHPC mixed with steel fibers and polypropylene fibers at the interface with prefabricated concrete. The experimental results indicate that the bonding strength of the UHPC-concrete interface experiences a slight improvement during the early stages of heating (100˚C) under high-temperature conditions. However, with further temperature increases, the bonding strength at the interface deteriorates. The influence of high temperatures on the bonding properties becomes more significant, with a loss of bonding strength ranging from 30% to 40% when the heating temperature reaches 500˚C. Considering the high-temperature resistance to cracking and the degradation of mechanical properties at the UHPC wet joint interface, a favorable bonding property with precast concrete interface is achieved when the UHPC material is mixed with 2 wt% of steel fibers and 0.5 wt% of polypropylene fibers.