Tensile behavior of half grouted sleeve connection at elevated temperatures

Half grouted sleeve connection is widely used in joining rebars in precast concrete structures. However, its mechanical behaviors at elevated temperatures remain to be a topic with little research. This paper presents experimental results of 12 half grouted specimens and 12 single rebars under static tension at different temperatures. The tensile properties of half grouted sleeve connection were found to be directly affected by the temperature, and some characteristics are different from that of the rebar. The results showed that the half grout sleeves exhibited two types of failure, namely rebar fracture and rebar pullout due to bonding failure. The mechanical properties of specimens were similar to that of single rebars. When the temperature elevated, the failure mode and rebar breakpoint location may change. The bonding length that would be sufficient at room or low temperature, becomes insufficient at 600 °C. Suggestions about the bond length are given to avoid rebar pull out from the grout due to bond failure at elevated temperature.