Work

Influence of mix design method on the shear capacity of reinforced concrete beams made with high‐quality recycled coarse aggregate

Year: 2026

Type: article

Abstract: This study investigates the shear capacity behavior of reinforced concrete (RC) beams without stirrups incorporating recycled coarse aggregate (RCA). An extensive database comprising 269 experimental data points from 40 journal articles published between 2001 and 2025 was compiled, excluding specimens with recycled fine aggregate or fiber reinforcement. Key parameters analyzed include RCA replacement ratio, shear span‐to‐effective depth ratio ( a / d ), longitudinal reinforcement ratio ( ρ ), concrete compressive strength, RCA water absorption (WA), and effective depth (d). The analysis indicates that the normalized shear capacity of RAC is strongly influenced by a / d , with deep beams showing greater variability and sensitivity to RCA replacement, while beams with larger a / d generally maintain stable performance. Overall, RAC specimens with adequate compressive strength and moderate RCA replacement levels exhibit normalized shear capacities comparable to or exceeding those of conventional concrete, although unfavorable parameter combinations at full replacement may lead to reduced performance. Experimental tests on eight RC beams with up to 50% RCA using an optimized equivalent mortar volume (EMV) mix design demonstrated comparable crack patterns, diagonal cracking strength, and ductility before peak load relative to natural aggregate control beams, though post‐peak failure was more brittle. Comparison with eight international design provisions shows that the shear capacity of high‐quality RAC generally exceeds code‐based predictions, while maintaining conservative lower‐bound estimates in most cases. In addition, RAC produced using EMV‐based mix designs exhibits consistently superior normalized shear capacity compared with conventionally mixed RAC, particularly at moderate RCA replacement levels up to 50%. These findings provide critical insights for sustainable concrete design and support the development of accurate shear capacity prediction models for recycled aggregate concrete beams.

Source: Structural Concrete

DOI: 10.1002/suco.70574

Author: Sungchul Yang

Institution: Hongik University

Language: English

Topic: Recycled Aggregate Concrete Performance

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: hybrid

Estimated APC paid: $3,820