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Title: High-Temperature Behavior of Lightweight Aggregate Reinforced Concrete Beams

Author(s): F. Dabbaghi, A. Tanhadoust, M. L. Nehdi, M. Dehestani, H. Yousefpour, and H.-T. Thai

Publication: Materials Journal

Volume: 119

Issue: 5

Appears on pages(s): 199-212

Keywords: finite element analysis; flexural capacity; lightweight aggregate; post-fire response; reinforced concrete; residual strength; stress-strain relationship

DOI: 10.14359/51736093

Date: 9/1/2022

Structural lightweight-aggregate concrete (LWAC) has gained a broad range of applications in the construction industry owing to its reduced dead load and enhanced fire resistance. In this study, the potential of using lightweight expanded clay aggregates as a partial replacement for fine and coarse natural aggregates was experimentally and numerically examined. Testing was performed on cylindrical specimens made of normalweight and lightweight concrete incorporating microsilica as a partial replacement for cement to determine the associated stress-strain behavior. Subsequently, three-point bending testing was conducted on reinforced concrete beams to evaluate their structural behavior. Four levels of temperature were considered: 25°C (ambient temperature), and 250, 500, and 750°C (elevated temperatures). The finite element method through Abaqus software was deployed to numerically investigate the behavior at elevated temperatures through a comprehensive parametric study. The experimental and numerical results indicate that under high-temperature exposure, LWAC outperforms its normal counterpart in terms of strength, stiffness, and Young’s modulus. It is also noticeable that LWAC beams retained their load-bearing capacity better than normal weight aggregate concrete (NWAC) after reaching the peak load.