AbstractThe ultrahigh-performance concrete (UHPC)-normal strength concrete (NSC) composite has been increasingly used for improving mechanical performance and durability of engineering structures. The UHPC-NSC composite structures in operation will be subjected to environmental loading (i.e., seasonal temperatures). The present study aimed to investigate the bond strength of the high-early-strength ultrahigh-performance concrete (HESUHPC)-NSC composite using a designed tensile specimen within normal seasonal temperatures (summer, autumn, and winter), in Changsha, China. The effect of the HESUHPC age and typical seasonal temperatures on the bond strength is discussed. It was found that in extreme conditions (i.e., 1-day age in winter), the pure interface failure occurred in the HESUHPC-NSC composite. The tensile bond strength of the HESUHPC-NSC composite increased with the age, and the early strength increased rapidly. However, the increase rate was affected by the typical seasonal temperatures. Moreover, the tensile bond strength of the HESUHPC-NSC composite decreased from summer to winter, and the differences were significant at the early age. The present study might provide valuable data for the application of the HESUHPC-NSC composite in different seasons.