A Comparative Study on the Flexural Behavior of UHPC Beams Reinforced with NPR and Conventional Steel Rebars
Abstract
1. Introduction
2. Brief Description of Experimental Program
2.1. UHPC Beam Specimens Reinforced with HRB 600 Steel Rebars
2.2. UHPC Beam Specimens Reinforced with NPR Steel Rebars
2.3. Direct Tensile Test of Reinforced UHPC
2.4. Materials Properties
3. Test Results and Discussions
3.1. Crack Pattern of UHPC Beams
3.2. Load-Deflection Curves of UHPC Beams
3.3. Tensile Load–Strain Curve of Direct Tensile Reinforced UHPC Specimens
3.4. AE Evolution of Direct Tensile Reinforced UHPC Specimens
4. Damage Mechanism Analysis
5. Conclusions
- (1)
- Unlike the single main crack typical of HRB 400-reinforced UHPC beams, beams with HRB 600 rebar under balanced–reinforced failure transitioned to failure via a few (2–3) main cracks. In contrast, the NPR-reinforced UHPC beams developed multiple (6–8) uniformly distributed main cracks within the pure bending region.
- (2)
- Both the HRB 600 and NPR steel rebars significantly enhanced the load-bearing capacity and deformation ability of the reinforced UHPC beams given a certain longitudinal reinforcement ratio.
- (3)
- The AE analysis method provided robust detection of sub-0.01 mm defects while elucidating the micro-level damage evolution process in the reinforced UHPC specimens.
- (4)
- The superior and distinct tensile characteristics of NPR steel rebar could promote effective stress transfer resulting from minimizing the strain differential between the rebar and the UHPC. Besides, NPR steel rebar might mitigate localized crack deterioration while offsetting the strength reductions from fiber bridging failure.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Test Batch | Specimen ID | Type of Cross-Section | Type of Steel Rebar | Longitudinal Reinforcement | Reinforcement Ratio |
---|---|---|---|---|---|
The first part of the beams | R-400-2.62% | Rectangle | HRB 400 | 3C20 | 2.62% |
R-600-2.62% | Rectangle | HRB 600 | 3E20 | 2.62% | |
T-400-2.91% | T-shape | HRB 400 | 4C20 | 2.91% | |
T-600-2.91% | T-shape | HRB 600 | 4E20 | 2.91% | |
The second part of the beams | R-400-1.72% | Rectangle | HRB 400 | 2C16 | 1.72% |
R-400-2.58% | Rectangle | HRB 400 | 3C16 | 2.58% | |
R-NPR-1.72% | Rectangle | NPR | 2N16 | 1.72% | |
R-NPR-2.58% | Rectangle | NPR | 3N16 | 2.58% |
Specimen Batch | Type of Steel Rebar | Diameter (mm) | Yielding Strength (MPa) | Ultimate Strength (MPa) | Elongation (%) |
---|---|---|---|---|---|
The first part of the beam specimens | HRB 400-1 | 20 | 480 | 613 | 16.6 |
HRB 600 | 20 | 670 | 749 | 12.7 | |
The second part of the beam specimens | HRB 400-2 | 16 | 425 | 575 | 14.0 |
NPR steel rebar | 16 | 645 | 1097 | 40.3 | |
Direct tensile specimens | HRB 400-2 | 16 | 425 | 575 | 14.0 |
HRB 600 | 16 | 670 | 749 | 12.7 | |
NPR steel rebar | 16 | 645 | 1097 | 40.3 |
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Gu, J.-B.; Chen, Y.-H.; Tao, Y.; Wang, J.-Y.; Zhang, S.-X. A Comparative Study on the Flexural Behavior of UHPC Beams Reinforced with NPR and Conventional Steel Rebars. Buildings 2025, 15, 2358. https://doi.org/10.3390/buildings15132358
Gu J-B, Chen Y-H, Tao Y, Wang J-Y, Zhang S-X. A Comparative Study on the Flexural Behavior of UHPC Beams Reinforced with NPR and Conventional Steel Rebars. Buildings. 2025; 15(13):2358. https://doi.org/10.3390/buildings15132358
Chicago/Turabian StyleGu, Jin-Ben, Yu-Han Chen, Yi Tao, Jun-Yan Wang, and Shao-Xiong Zhang. 2025. "A Comparative Study on the Flexural Behavior of UHPC Beams Reinforced with NPR and Conventional Steel Rebars" Buildings 15, no. 13: 2358. https://doi.org/10.3390/buildings15132358
APA StyleGu, J.-B., Chen, Y.-H., Tao, Y., Wang, J.-Y., & Zhang, S.-X. (2025). A Comparative Study on the Flexural Behavior of UHPC Beams Reinforced with NPR and Conventional Steel Rebars. Buildings, 15(13), 2358. https://doi.org/10.3390/buildings15132358