Experimental Study on Fracture Properties of Hybrid Fiber Reinforced Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 518-522 ◽  
Author(s):  
Yun Da Shao ◽  
Wen Feng Wang

Though fracture test on the fifteen specimens with notch of hybrid fiber reinforced concrete with the size of 100mm×100mm×400mm, this paper explores the hybrid effect between steel fiber and polypropylene fiber and impact on the fracture properties, such as critical effective crack length, critical crack tip opening displacement, effective stress intensity factors and fracture energy. The test results indicate that the addition of fiber is helpful to improve the fracture properties of concrete. Synergistic effect of two kinds of fibers is good, the steel fiber with high elastic module can restrain the cracking of concrete when the crack displacement is small, polypropylene macro-fiber with high ductility is more beneficial to increase the fracture properties of concrete than steel fiber when the crack displacement is big. The best fiber compounding can be gotten when the volume fractions of steel fiber and polypropylene fiber is respectively 0.5%and 1.0%in this experiment.

2021 ◽  
Vol 261 ◽  
pp. 02019
Author(s):  
Tu-Sheng He ◽  
Meng-Qian Xie ◽  
Yang Liu ◽  
San-Yin Zhao ◽  
Zai-Bo Li

The influence of steel fiber and polypropylene fiber mixed on compressive strength of high performance concrete (HPC) was studied. The steel fiber content (0.5%, 1.0%, 1.5%, 2.0%) (volume fraction, the same below), polypropylene fiber content (0.05%, 0.1%, 0.15%, 0.2%) and length (5mm, 6.5mm, 12mm, 18mm) were studied by L16 (45) orthogonal test for 28d ages, the range analysis and variance analysis of the test results are carried out, and the prediction model of compressive strength of hybrid fiber reinforced concrete was established. The results show that: The significant influence factor of concrete compressive strength is the volume fraction of polypropylene fiber, while the length of polypropylene fiber and the volume fraction of steel fiber are not significant; the concrete compressive strength with polypropylene fiber shows negative hybrid effect; The prediction model of compressive strength of hybrid fiber reinforced concrete has high accuracy, and the average relative errors is 2.96%.


2013 ◽  
Vol 652-654 ◽  
pp. 1237-1241
Author(s):  
Guo Dong Mei ◽  
Xiao Fan Liu ◽  
Ji Xiang Li ◽  
Wen Fu Duan

The cracking bending strength for steel-polypropylene hybrid fiber reinforced concrete (HFRC) had been studied based on experimental test. the inicial cracking strength achieve significant improvement compare to plain concrete, and the highest increase is 16.7%. There is a synergistic effect exist when steel fiber is 1.0% in volume or polypropylene fiber is 0.1% in volume, and the synergistic effect raise to vertex (1.043) when both of those two requirements are fulfilled.


2011 ◽  
Vol 239-242 ◽  
pp. 2006-2010
Author(s):  
Xiao Fan Liu ◽  
Guo Dong Mei ◽  
Ji Xiang Li ◽  
Yun Xia Lun

Orthogonal tests are designed for hybrid fiber reinforced concrete. Bending toughness of hybrid fiber reinforced concrete, with the substrate intensity C30, the quantity of the volume for the steel fiber dosage 0~1.5% and polypropylene fiber dosage 0~0.3%, are studied. The results show that the hybrid fibers significantly improve the toughness of the concrete matrix. When the dosage reaches to a certain number, the affection of fiber toughness is decreased. Based on the test results the best dosage of hybrid fibers which is the steel fiber 1% mixed with 0.1% polypropylene fiber is recommended.


2014 ◽  
Vol 906 ◽  
pp. 311-317
Author(s):  
Si Hui Xiong ◽  
Dong Tao Xia ◽  
Xiang Kun Liu

In order to focus on hybrid fiber reinforced concrete flexural toughness,mixed 0.7% steel fiber/0.3% modified polypropylene fiber reinforced concrete, mixed 0.89% steel fiber/0.11% Dura fiber reinforced concrete were chosen to perform flexural toughness test. The test method is giving a central point load to the notched beam specimens (H*B*L1:150mm*150mm*550mm, h1*B1:2mm*25mm) with a 0.2 mm/min loading rate. The load we carry out should not stop until the mid span deflection is more than 3mm.Based on calculating the contribution of the fiber to the energy absorption value Dcr when the concrete cracking,the contribution of the fiber to the energy absorption value D1f when mid-span deflection is δ1,the contribution of the fiber to the energy absorption value D2f when mid-span deflection isδ2 and the equivalent flexural tensile strength feq1,feq2,the effect of the way use to hybrid fiber on the flexural toughness of concrete were investigated. The results shows that the hybrid fiber can significantly improve the flexural toughness of concrete, have favorable deformability and the ability to control crack. The result of 0.7% steel fiber/0.3% modified polypropylene fiber reinforced concrete is shown: Dcr=2185 Nmm,D1f=7634.26 Nmm,D2f=2198.67 Nmm, feq1=4.89 MPa,feq2=2.83 MPa, hence it shows the positive enhancement effect of hybrid fiber and flexural toughness increase significantly.


2013 ◽  
Vol 438-439 ◽  
pp. 309-313
Author(s):  
Hong Yuan Huo ◽  
Liang Zhang ◽  
Tong Xing

Experiments were conducted to study the resistance of steel-polypropylene hybrid fiber reinforced concrete (HFRC) to freezing and tharwing. The mix proportions of concrete in strength grade CF40 were designed according to the superposition mix design method, where five mass contents of polypropylene fiber changing in range of 0.3~1.5kg/m3 with 0.3kg/m3 increment while the fraction of steel fiber by volume was constant as 1.0%, and four fractions of steel fiber by volume changing in range of 0.5~2.0% with 0.5% increment while the mass content of polypropylene fiber was kept as 0.9kg/m3. The results show that the steel-polypropylene hybrid fiber can significantly increase the resistance of HFRC to freezing and thawing, the losses of dynamic elasticity modulus and flexural strength of HFRC decrease with the increasing mass content of polypropylene fiber and fraction of steel fiber by volume, there is the coupling effect of enhancing on resistance of HFRC to freezing and thawing by hybrid fibers.


2021 ◽  
Vol 30 (2) ◽  
Author(s):  
Tao Zhang ◽  
Deng Pan

This study mainly analyzed the effect of steel fiber (SF) mixed with polypropylene fiber (PF) on the performance optimization of concrete. Firstly, the steel fiber reinforced concrete (SFRC), polypropylene fiber reinforced concrete (PFRC) and steel-polypropylene hybrid fiber reinforced concrete (SP-HFRC) specimens were designed. Then, the slump experiment, compressive strength experiment, and tensile strength experiment were carried out. The results demonstrated that the increase of fibers reduced the slump, and the influence of PF on the slump was the largest, followed by SF and SP; when the content of SF was 1% and the content of PF was 0.1%, the compressive strength and tensile strength of the concrete were 73.16 MPa and 6.33 MPa, which was superior to the concrete mixed with single fiber. The experimental results demonstrate that SP-HFRC has a superiority in mechanical property and can be further promoted and applied in building structure.


2020 ◽  
Vol 12 (7) ◽  
pp. 168781402094402
Author(s):  
Dong An ◽  
Zheng Chen ◽  
Linghan Meng ◽  
Guangyao Cui

The fault-crossing tunnel in meizoseismal area is directly subjected to strong ground motion, which leads to the failure of the tunnel lining. In order to improve the seismic safety of tunnel, fiber-reinforced concrete is applied to tunnel lining in this article. Taking the section of Zhongyi tunnel crossing Wanlong fault as an example, seismic performance of fiber-reinforced concrete tunnel lining was studied by finite difference numerical calculation software FLAC3D. The seismic displacement, stress response, and side wall convergence of secondary lining structures which are plain concrete, steel fiber-reinforced concrete, and steel-basalt hybrid fiber-reinforced concrete were comparatively analyzed. Moreover, the safety factor of each lining structure was investigated with the present numerical model. With the obtained data, seismic performance of steel-basalt hybrid fiber-reinforced concrete secondary lining is better than that of steel fiber-reinforced concrete secondary lining. The results may provide references for seismic design of fault-crossing tunnels in meizoseismal area.


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