Mechanical properties of grouted sleeve splice with horizontal grouting defect after exposure to high temperature

Abstract

Grouted sleeve splice is an important part of prefabricated concrete components. The performance and reliability of structures are directly impacted by the grouted sleeve splice between the steel bar and grouted sleeves. After exposure to high temperatures, the horizontal grouting defects are of great significance in terms of the mechanical properties of grouted sleeve splices. The mechanical properties of grouted sleeve splices at five horizontal grouting defect rates (0, 10, 15, 20, 25 and 30 %) after being exposed to four kinds of temperatures (room temperature, 200, 400 and 600 °C) were analyzed. The defect rate refers to the mass of missing grout within the grouted sleeve as a percentage of the grout mass in a fully grouted sleeve. The findings demonstrated that rebar fracture and rebar pull-out were the main causes of the failure of the grouted sleeve splice. Only the grouted sleeve splice with defect rate of 30 % exhibited the rebar pull-out failure under room temperature. The compressive strength of the grout gradually decreased with increasing temperature. After exposure to 600 °C, the strength had declined by approximately 50 % compared to ambient conditions. After exposure to 600 °C, the mechanical properties of rebars began to degrade, and the yield strength and ultimate strength of rebars decreased by 6.1 % and 5.9 % respectively compared with normal temperature. Furthermore, for the specimens with a defect rate of 10 %, the failure mode shifted from rebar fracture to rebar pull-out as the temperature rose to 600 ℃. The drastic decline in ultimate load of the grouted sleeve splice led to a significant reduction in ultimate slippage.