Flexural behavior of ultra‐high performance concrete filled high‐strength steel tube

2021 ◽  
Author(s):  
Jiayue Li ◽  
Zongcai Deng ◽  
Tong Sun
Keyword(s):  
High Strength Steel ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Ultra High Performance Concrete

scholarly journals Evaluation of the nano silica and nano waste materials on the corrosion protection of high strength steel embedded in ultra-high performance concrete

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahar A. Mostafa ◽  
Mohamed M. EL-Deeb ◽  
Ahmed A. Farghali ◽  
A. Serag Faried
Keyword(s):  
High Strength Steel ◽  
High Performance ◽  
Open Circuit Potential ◽  
High Performance Concrete ◽  
High Strength ◽  
Open Circuit ◽  
Nano Materials ◽  
Nano Silica ◽  
Ultra High Performance Concrete ◽  
Transfer Resistance

AbstractCorrosion resistance of high strength steel (HHS) embedded in ultra-high performance concrete (UHPC) immersed in 3.5% NaCl solution is evaluated in the absence and presence of nano silica (NS), nano glass waste (NGW), nano rice husk ash (NRHA) and nano metakaolin (NMK) using open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) under normal and accelerated conditions. Data showed that the corrosion rate in the accelerated conditions is higher compared by the normal conditions due to the increasing in the rate of both anodic and cathodic reactions in the presence of anodic current. On the other hand, the presence of the studied nano materials decreases both the anodic and cathodic overpotentials, and shifts both the open circuit potential (Eocp) and corrosion potential (Ecorr) of HSS to more noble values, as well as decreases the values of the corrosion current densities (Icorr) in both normal and accelerated conditions. Furthermore, EIS analysis illustrates that the presence of these materials enhances both the concrete bulk resistance and the charge transfer resistance at HSS/UHPC interface, which retards the flow of the electrons between the anodic and cathodic sites, thus impeding the propagation of the corrosion process. The inhibitory effect of the studied nano materials for the corrosion of HSS is interpreted on the basis of the change in the microstructure and the compressive strength of the UHPC.

scholarly journals Experimental Investigation of Flexural Behavior of Ultra-High-Performance Concrete with Coarse Aggregate-Filled Steel Tubes

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6354
Author(s):  
Fanghong Wu ◽  
Yanqin Zeng ◽  
Ben Li ◽  
Xuetao Lyu
Keyword(s):  
Experimental Investigation ◽  
High Performance ◽  
Coarse Aggregate ◽  
High Performance Concrete ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Flexural Stiffness ◽  
Flexural Capacity ◽  
Ultra High Performance Concrete ◽  
Steel Tubes

This paper presents an experimental investigation of flexural behavior of circular ultra-high-performance concrete with coarse aggregate (CA-UHPC)-filled steel tubes (CA-UHPCFSTs). A total of seven flexural members were tested under a four-point bending load. The failure modes, overall deflection curves, moment-versus-curvature relationships, moment-versus-strain curves, strain distribution curves, ductility, flexural stiffness and ultimate flexural capacity were evaluated. The results indicate that the CA-UHPCFSTs under bending behaved in a good ductile manner. The CA-UHPC strength has a limited effect on the ultimate flexural capacity, while the addition of steel fiber can improve the ultimate flexural capacity. Increasing the steel tube thickness leads to higher flexural stiffness and ultimate flexural capacity. There is a significant confinement effect between the steel tube and the CA-UHPC core in the compressive zone and centroidal plane after the specimen enters the elastic-plastic stage, while the confinement effect in the tensile zone is minimal. Moreover, the measured flexural stiffness and ultimate flexural capacity were compared with the predictions using various design specifications. Two empirical formulas for calculating the initial and serviceability-level flexural stiffness of CA-UHPCFSTs are developed. Further research is required to propose the accurate design formula for the ultimate flexural capacity of CA-UHPCFSTs.

Shear strength of fiber-reinforced high-strength steel ultra-high-performance concrete beams based on refined calculation of compression zone depth considering concrete tension

2019 ◽  
Vol 22 (8) ◽  
pp. 2006-2018 ◽  
Author(s):  
Jianan Qi ◽  
Xiaomeng Ding ◽  
Zhen Wang ◽  
Yuqing Hu
Keyword(s):  
Shear Strength ◽  
High Strength Steel ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
Limit State ◽  
High Strength ◽  
Test Results ◽  
Compression Zone ◽  
Ultra High Performance Concrete

This article presents an experimental and theoretical investigation on the shear behavior of fiber-reinforced ultra-high-performance concrete beams reinforced with high-strength steel. The test parameters included the fiber volume fraction, fiber type, and stirrup ratio. The test results indicate that the shear failure in ultra-high-performance concrete beams is not brittle and catastrophic but has ductility characteristics. A moderate quantity of stirrups can significantly improve the shear behavior of ultra-high-performance concrete beams, as reflected in the thorough propagation of cracks in both shear span and pure bending zone. The depth of the compression zone considering concrete tension was derived based on the deformation compatibility and force equilibrium equations for both serviceability limit state and ultimate limit state. The comparison of the proposed method and classical beam theory shows that the concrete tension should not be neglected in the serviceability limit state analysis. After cracking, the concrete tension can be neglected for simplicity when the beam is heavily reinforced and should be considered when the beam is lightly reinforced. Then, a shear strength model was established based on Rankine’s failure criteria, the truss model, and Association Francaise de Génie Civil-Sétra. Finally, the proposed shear strength equation was verified by the test results and compared with other shear strength equations.

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