Load-bearing capacity of precast recycled aggregate concrete column-to-column connections

Abstract

Recycled aggregate concrete (RAC) often shows different strength and deformation properties from 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 partially or fully replace 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 show that regardless of RCA content, the equation specified in ACI 318 (ACI, 2019) and the one proposed by Vambersky (1990) provide safe estimates of the load-bearing capacity of wet connections between reinforced RAC columns.