Self-monitoring of stresses in grouted sleeves using smart grout

Abstract

Currently, grouted sleeves are widely used in the connection of prefabricated reinforced concrete (RC) members. The mechanical performance of a connection joint is critical to the safety and durability of structures, and traditional monitoring techniques have many limitations. This paper proposes a stress self-monitoring approach based on the smart grout in which the structural and sensing functions are perfectly combined. A theoretical model was proposed to address the relationship between the sensing sensitivity and the uniaxial tensile load. The influence of the rebar embedment length on the sensitivity was investigated. Then, experiments were performed to verify the self-monitoring performance of smart grouted sleeves. Moreover, the stress self-monitoring performance of the smart grouted sleeves was compared to that of traditional grouted sleeves. The results revealed that the sensitivity increased with the uniaxial tension, and the sensitivity decreased as the embedded length of the rebar in the sleeves decreased in the theoretical model. The effectiveness of the proposed model was verified with a comparison between the calculated and experimental results. When the rebar yielded, the value of the damage coefficient ω was less than 3%, and the sensing sensitivity was close to 20% in the pull-out test. When the destruction approached, the value of ω exceeded 7% or more. This investigation provides a theoretical and experimental basis for the application of the smart grouted sleeves in actual engineering.