Influence of RPC grouting materials on shear behavior of wet joints in PCSBs with confining stress

Abstract

Reactive power concrete (RPC), an advanced cement-based material, has excellent mechanical properties. The cast-in-place wet joints are located in the middle of precast concrete segmental beams (PCSBs) which could eliminate the errors caused by the assembly of the precast concrete segments. Due to the discontinuity of the reinforcements and complicated stress conditions, those wet joints are the weak parts in the PCSBs. Pouring RPC grouting materials in wet joints could effectively improve the cracking resistance. This research not only puts emphasis on the influence of the geometry of wet joints, including shear key depth (25 mm, 35 mm, and 45 mm), but also reveals the influence of confining stress (0.5 MPa and 2.0 MPa), different concrete type (PRC with and without steel fibers), and different volume fractions of steel fibers (0.5% and 2.0%) on shear behavior. The results showed that higher shear capacity of RPC joints could be obtained by exerting a higher confining stress on the specimens, or using a concrete with higher tensile strength. Shear capacity of RPC joint with 2.0% steel fibers in volume fraction increased by 67.87% than that with 0.5% steel fibers in volume fraction. The AASHTO 2003 formula overestimated the shear capacity of the wet joints, showing an average ratio of calculated results to the experimental ones of 1.69, with a standard deviation of 0.53. A simplified formula was proposed to calculate the shear capacity of RPC joints based on tensile strength of concrete and Mohr's circle. The results from the simplified formula were found to agree well with the experimental values, inferred from an average ratio of the predicted values to experimental results of 1.10, with a standard deviation of 0.12.