Effect of corroded stirrups on shear behavior of reinforced recycled aggregate concrete beams strengthened with carbon fiber-reinforced polymer

2019 ◽  
Vol 161 ◽  
pp. 357-368 ◽  
Author(s):  
Huifeng Zhang ◽  
Jin Wu ◽  
Fengyu Jin ◽  
Chengjun Zhang
Keyword(s):  
Carbon Fiber ◽  
Concrete Beams ◽  
Shear Behavior ◽  
Recycled Aggregate Concrete ◽  
Fiber Reinforced Polymer ◽  
Recycled Aggregate ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Reinforced Polymer

scholarly journals Ductility Evaluation of Damaged Recycled Aggregate Concrete Columns Repaired With Carbon Fiber-Reinforced Polymer and Large Rupture Strain FRP

2020 ◽  
Vol 7 ◽  
Author(s):  
Pengda Li ◽  
Yao Zhao ◽  
Xu Long ◽  
Yingwu Zhou ◽  
Zhenyuan Chen
Keyword(s):  
Concrete Columns ◽  
Recycled Aggregate Concrete ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Recycled Aggregate ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Reinforced Polymer ◽  
Concrete Cylinders

The inherent defects of recycled aggregate concrete (RAC) include the complex interfacial transition zone (ITZ) and the many micro-cracks that appear during its producing process, which result in some inferior mechanical properties compared with natural aggregate concrete (NAC). This drawback usually prevents RAC from being selected for structural purposes. Existing research has shown that the strength and ductility of damaged concrete in compression members can be significantly enhanced through external confinement using fiber-reinforced polymer (FRP) wraps. This application has been widely used in concrete structural repair and retrofitting technology. However, research on the effects of RAC damage coupled with different load damage conditions is rare, as is information on the mechanical properties of RAC reinforced with FRP jackets. This paper presents the results of an experimental study on the behavior of pre-damaged recycled aggregate concrete cylinders that were repaired with carbon fiber-reinforced polymer (CFRP) or large rupture strain (LRS)-FRP jackets. Tests were conducted on 58 concrete cylinders with variations in the replacement ratio, damage levels, and FRP properties. Test results demonstrated that the ultimate strain and strength of damaged recycled aggregate concrete could be significantly enhanced by FRP jackets and that aggregate quality plays a vital role in the strength of confined concrete. Also, the energy absorption of CFRP- and LRS-FRP-confined RAC were evaluated. The analysis indicated that, compared with CFRP-confined RAC, LRS-FRP can greatly improve the energy absorption capacity of RAC; thus, LRS-FRP confined concrete has a good potential to achieve a ductile design for concrete columns, especially when used in seismic reinforcement.

scholarly journals Shear behavior of concrete beams pre-stressed with carbon fiber reinforced polymer tendons

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401881687
Author(s):  
Zuohu Wang ◽  
Yuan Yao ◽  
Du Liu ◽  
Yuqiang Cui ◽  
Weizhang Liao
Keyword(s):  
Carbon Fiber ◽  
Failure Mode ◽  
Concrete Beams ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

This article presents experimental and numerical studies on the shear behavior of reinforced concrete beams pre-stressed with carbon fiber reinforced polymer tendons. A total of 23 beams were tested to analyze the failure mode and shear performance of pre-stressed concrete beams. Experimental results revealed that there were two typical shear failure modes, that is, shear compression failure and inclined compression failure. Next, the experimental and numerical results were used to explore factors influencing the failure mode and the shear behavior of the concrete beams, including the type of pre-stressing tendons, stirrup ratio, shear span–depth ratio, number of pre-stressing tendons, and their initial pretension levels. It is demonstrated that shear span–depth ratio and stirrup ratio are the two main determinants of the failure mode and shear capacity of the concrete beams pre-stressed with carbon fiber reinforced polymer tendons. However, the bonding conditions of the pre-stressing carbon fiber reinforced polymer tendons have no significant effect on the shear capacity of the pre-stressed concrete beam.

Restoring Initially Cracked Reinforced Concrete Beams utilizing Carbon Fiber Reinforced Polymer Strips

2019 ◽  
Vol 7 (1) ◽  
pp. 30-34
Author(s):  
A. Ajwad ◽  
U. Ilyas ◽  
N. Khadim ◽  
Abdullah ◽  
M.U. Rashid ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Loading Test ◽  
Control Beam ◽  
Reinforced Polymer ◽  
Cfrp Sheet ◽  
Carbon Fiber Reinforced

Carbon fiber reinforced polymer (CFRP) strips are widely used all over the globe as a repair and strengthening material for concrete elements. This paper looks at comparison of numerous methods to rehabilitate concrete beams with the use of CFRP sheet strips. This research work consists of 4 under-reinforced, properly cured RCC beams under two point loading test. One beam was loaded till failure, which was considered the control beam for comparison. Other 3 beams were load till the appearance of initial crack, which normally occurred at third-quarters of failure load and then repaired with different ratios and design of CFRP sheet strips. Afterwards, the repaired beams were loaded again till failure and the results were compared with control beam. Deflections and ultimate load were noted for all concrete beams. It was found out the use of CFRP sheet strips did increase the maximum load bearing capacity of cracked beams, although their behavior was more brittle as compared with control beam.

scholarly journals Study of Mechanical Properties of an Eco-Friendly Concrete Containing Recycled Carbon Fiber Reinforced Polymer and Recycled Aggregate

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4592
Author(s):  
Chen Xiong ◽  
Tianhao Lan ◽  
Qiangsheng Li ◽  
Haodao Li ◽  
Wujian Long
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Fiber Reinforced Polymer ◽  
Recycled Aggregate ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Flexural Performance ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

This study investigates the feasibility of collaborative use of recycled carbon fiber reinforced polymer (RCFRP) fibers and recycled aggregate (RA) in concrete, which is called RCFRP fiber reinforced RA concrete (RFRAC). The mechanical properties of the composite were studied through experimental investigation, considering different RCFRP fiber contents (0%, 0.5%, 1.0%, and 1.5% by volume) and different RA replacement rates (0%, 10%, 20%, and 30% by volume). Specifically, ten different mixes were designed to explore the flowability and compressive and flexural strengths of the proposed composite. Experimental results indicated that the addition of RCFRP fibers and RA had a relatively small influence on the compressive strength of concrete (less than 5%). Moreover, the addition of RA slightly decreased the flexural strength of concrete, while the addition of RCFRP fibers could significantly improve the flexural performance. For example, the flexural strength of RA concrete with 1.5% RCFRP fiber addition increased by 32.7%. Considering the good flexural properties of the composite and its potential in reducing waste CFRP and construction solid waste, the proposed RFRAC is promising for use in civil concrete structures with high flexural performance requirements.

Friction Loss of Externally Prestressed Concrete Beams with Carbon Fiber-Reinforced Polymer Tendons

2010 ◽  
Vol 163-167 ◽  
pp. 3701-3706 ◽  
Author(s):  
Tian Lai Yu ◽  
Li Yuan Zhang
Keyword(s):  
Friction Coefficient ◽  
Carbon Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Friction Loss ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
External Prestressing ◽  
Carbon Fiber Reinforced

Friction loss is an important component of the calculation of prestressing loss for external prestress strengthening technology. Unfortunately, the test data of relevant curvature friction and wobble coefficients is scarce, especially for beams strengthened by external prestressing Carbon Fiber-Reinforced Polymer (CFRP) tendons. Through the experiment of 12 concrete beams strengthened by external prestressing CFRP tendons, this study attempts to discuss the friction loss algorithm and the reasonable value of friction coefficient. The test results demonstrated that traditional friction loss algorithm for prestressed steel tendons is also suit to external prestressing CFRP tendons, but the value of curvature and wobble coefficients should be determined by different types of CFRP tendons and saddle design. What is more, aiming at the domestic production of CFRP tendons and the adopted special saddle design in this paper, the curvature friction coefficient is 0.263 and the wobble coefficient is 0.0067 at the deviator. Results of the research provide a reference for external prestress strengthening design with CFRP tendons.

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