Behavior of Recycled Aggregate Concrete Slender Column under Concentric Axial Loading

Abstract

This investigation investigates the structural behavior of slender reinforced concrete RC containing different RCA replacement portions in addition to the slenderness effect. To perform this, eight (8) slender RC columns with two main types of transverse reinforcement (ties and spiral reinforcement) and three recycled coarse aggregate RCA replacement percentages (25, 50, and 100%) were modeled and subjected to axial concentric loading. The gathered experimental results are monitored and analyzed to better estimate the structural characteristics of the RC slender column (The ultimate carrying load, first cracking load, load-displacement curve, and load-strain response). The results showed that replacing NCA with (25, 50, and 100%) of RCA reduced the ultimate capacity of tied RC columns by (13.41, 14.07, and 23.33%), respectively, and reduced their first cracking load values by (19.64, 15.96, 22.50%), respectively. The reduction in ultimate load capacity and the first cracking load were (4.10, 17.33, 22.63%) and (12.26, 23.15, 25.00%) for spirally RC columns, respectively. Spiral transverse reinforcement slightly increases the carrying load capacity compared to tie reinforcement. It delays the fast propagation of the first cracking load, furthers the effect of spiral reinforcement in improving the deformation capacity, reducing the longitudinal and lateral mid-height strains, and developing the flexural stiffness of the load-displacement curve.