Tensile and flexural tests on ultrahigh performance concrete grouted sleeve connection

Abstract

AbstractConnections in the assembled precast elements become essential locations for creating structural continuity. However, the construction challenges of conventional steel sleeve connections, such as rebar embedment length, rebar congestion, and formed grout defects (i.e., voids), are still a concern area for researchers and engineers. In this study, a proposed ultrahigh performance concrete (UHPC) grouted sleeve connection was presented for assembled precast elements, which might reduce defects, enhance durability, and accelerate structure construction. The tensile test of grouted sleeve connection with different grouting materials, rebar diameters, and anchoring lengths was conducted to determine an optimal anchoring length used in the flexural design. The precast specimens with the UHPC grouted sleeve connection were tested under flexural load. Also, strain changes in concrete, sleeve, and rebar were reported in tensile and flexural tests. The tensile test results showed two types of failure modes, the rebar rupture and bond failure between rebar and grouting. The recommended rebar anchoring length in the flexural design was six times the rebar diameter. The flexural test results showed that the precast specimen with or without the shear key has a similar failure mode as compared to the cast‐in‐place specimen, while their average cracking load, yield load, and ultimate load were 27.9%, 11.0%, and 7.4%, respectively, which is less than those of the cast‐in‐place specimen. Also, the flexural cracking resistance was the highest in the sleeve segment, followed by the joint region and the rebar segment. This study provides a reference for the design of the UHPC grouted sleeve connection for assembled precast elements.