The bond between tendons and grout is crucial to the performance of bonded post-tensioned concrete structures. To study the bond performance of grouted tendons at elevated temperatures, pull-out tests were conducted on specimens comprising either a mono- or multi-strand tendon located centrally within a grouted duct inside a concrete cylinder, at test temperatures of 20–600°C. It was found that the bond strength deteriorated with a rise in temperature and the degradation of bond strength was more severe than that of other mechanical properties. Three types of failure mode were observed: pull-out, partial splitting and through splitting. The use of a smaller duct could improve the bond strength of specimens failing in pull-out mode. The influence of the strength of the outer concrete was found to be insignificant. Based on the distinct bond behaviour of different failure modes, a bond–slip model was developed by regression of the test results.

中文翻译：

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灌浆筋在高温下的粘结性能

钢筋束和灌浆之间的粘合对粘合后张混凝土结构的性能至关重要。为了研究灌浆钢筋在高温下的粘结性能，在 20–600°C 的测试温度下，对包含位于混凝土圆柱体内灌浆管道中央的单股或多股钢筋的试样进行了拉拔试验. 发现粘结强度随温度升高而下降，粘结强度的下降比其他力学性能下降的更为严重。观察到三种类型的故障模式：拔出、部分分裂和贯通分裂。使用较小的管道可以提高在拔出模式下失败的试样的粘合强度。发现外部混凝土强度的影响是微不足道的。