scholarly journals Shear Bond between Ultra-High Performance Fibre Reinforced Concrete Overlays and Normal Strength Concrete Substrates

2021 ◽  
Vol 13 (15) ◽  
pp. 8229
Author(s):  
Sara Javidmehr ◽  
Martin Empelmann

Strengthening or retrofitting of existing structures is a more sustainable and resource-efficient solution than replacing them with new constructions. To enhance the performance and effectiveness of strengthening works the use of high-performance materials is a promising method. Using ultra-high performance fibre reinforced concrete (UHPFRC) as supplementary concrete is one of such solutions leading to high structural resistance and better durability. For such UHPFRC overlays the shear bond resistance of the interface between the existing substrate, usually normal strength concrete (NSC), and the UHPFRC is a significant design aspect. This paper presents the results of push-off tests conducted on NSC-UHPFRC specimens, which were produced with different substrate treatment methods. Using different surface measurement techniques including the sand patch method and digital microscopy, the effects of substrate roughness and treatment method on shear bond behaviour and failure mechanisms are investigated, and the results are analysed with design approaches and further calculation models in the technical literature. Based on the results, the significance of considering roughness parameters and failure mode for the design of high-performance overlays is highlighted. Furthermore, the effectiveness of different substrate treatment methods is discussed and an effective treatment method is suggested.

Author(s):  
Charles K.S. Moy ◽  
Jun Xia ◽  
Chee Chin ◽  
Jianzhong Liu

Ultra-high performance fibre reinforced concrete (UHPFRC) has very high compressive strength up to 200 MPa and exhibits strain hardening effects under flexural loading. The bond strength between UHPFRC and steel reinforcement is much better than the normal strength concrete. Therefore, there is a potential to use UHPFRC material at the beam-column joint region to reduce the congestion of reinforcement as well as to improve the seismic resistance of the structure. In this pilot study, the beam column joints made of normal strength concrete and UHPFRC were tested under lateral cyclic loading up to failure using a 500 tonne capacity computer control servo hydraulic machine. The specimen with normal strength concrete failed at the joint region while the specimen with UHPFRC material failed due to yielding of the rebars in the beam sections near the column face and no obvious cracks were observed at the joint area. The specimens with UHPFRC as joint material exhibited higher initial lateral stiffness and achieved slightly higher ultimate load capacity than the specimen with normal strength concrete.


2013 ◽  
Vol 47 (10) ◽  
pp. 1773-1785 ◽  
Author(s):  
Pierre Rossi ◽  
Jean Philippe Charron ◽  
Maléna Bastien-Masse ◽  
Jean-Louis Tailhan ◽  
Fabrice Le Maou ◽  
...  

2018 ◽  
Vol 183 ◽  
pp. 02005
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni

The paper presents the results obtained on cylindrical Ultra High Performance Fibre Reinforced Concrete specimens with diameter of 30mm and a height of 60mm under compression at high stress rate (1.7–2.3 TPa/s). Four different percentages of fibre reinforcement are considered (1, 2, 3, and 4% fibre content) and compared with the results of the matrix (UHPC). A slight reduction of the strength and fracture time with the introduction of fibres is observed. The experimental results are analysed and discussed with the intent to better understand the mechanical behaviour of UHPFRC materials in case of dynamic event under service loading conditions.


2008 ◽  
Vol 17 (11) ◽  
pp. 316-317
Author(s):  
Daniel de MATTEIS ◽  
Pierre MARCHAND ◽  
Aude PETEL ◽  
Thierry THIBAUX ◽  
Nicolas FABRY ◽  
...  

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