Load-bearing capacity of precast high-strength self-compacting recycled aggregate concrete column-to-column connections

Recycled aggregate concrete (RAC) often shows different strength and deformation properties to natural aggregate concrete (NAC) and may therefore have an impact on the connections between precast concrete elements. In this work, three simple connections between precast concrete columns were considered, including a wet connection with bedding mortar, a dry connection without bedding mortar and a monolithic joint with plain concrete. An industrially produced coarse recycled concrete aggregate (RCA) was used to replace partially or fully a coarse natural aggregate in the concrete. A total of twenty-two 200 mm × 200 mm × 500 mm reinforced concrete columns were prepared and tested under axial monotonic loading through displacement control. The results showed that regardless of RCA content, the equation specified in ACI 318 (2019) and the one proposed by Vambersky (1990) provided safe estimates of the load-bearing capacity of wet connections between reinforced RAC columns.