Mechanical and Freeze-Thaw Durability Properties of Recycled Aggregate Concrete Made with Recycled Coarse Aggregate

TLDR

The study investigates how recycled coarse aggregates affect the fresh, hardened, and freeze‑thaw durability properties of recycled aggregate concrete. Four mixes were tested—one with natural aggregate and three with 30%, 40%, and 50% RCA replacement—using national standards to assess fresh and hardened properties, compressive strength at multiple ages, stress‑strain behavior, modulus of elasticity, Poisson’s ratio, and freeze‑thaw resistance. Results show that RAC performance slightly declines as RCA content increases, yet remains comparable to natural aggregate concrete, supporting its use for greener, sustainable construction.

Abstract

The influence of recycled coarse aggregates (RCAs) on the fresh, hardened, and freeze-thaw durability properties of recycled aggregate concrete (RAC) is investigated in the research reported in this paper. Four different mixes were considered with natural aggregate and three different replacement levels of RCA [i.e., (1) 30%, (2) 40%, and (3) 50%]. The fresh and hardened properties of RAC were investigated according to national standards where the target strength was 35 MPa in 56 days. The compressive strengths of different concrete mixes were determined after 3, 7, 28, 56, and 120 days of moist curing. The results are also presented in terms of stress-strain curves, modulus of elasticity, and Poisson’s ratio. Freeze-thaw durability performance of RAC was studied in accordance with a national standard. This paper shows that the performance of RAC slightly decreases with increasing RCA replacement levels; however, their overall performance is comparable to natural aggregate concrete (NAC). This paper indicates that the use of RCA in new concrete production can lead to a greener environment and pave the way for sustainable construction.