Effect of multi-scale polypropylene fiber hybridization on mechanical properties and microstructure of concrete at elevated temperatures

2021 ◽  
pp. 136943322098862
Author(s):  
Ninghui Liang ◽  
Xiufei You ◽  
Guojun Cao ◽  
Xinrong Liu ◽  
Zuliang Zhong
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Elevated Temperatures ◽  
Polypropylene Fiber ◽  
Plain Concrete ◽  
Splitting Tensile Strength ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Multi Scale ◽  
Polypropylene Fiber Reinforced Concrete

This paper presents results of an experimental study on the compressive and splitting tensile strength of plain concretes and concretes incorporated with macro, micro and hybrid polypropylene (PP) fibers at elevated temperatures (20 °C, 200 °C, 400 °C, 600 °C, and 800 °C). Nine series of concrete mixtures with different contents PP fibers were prepared and the optimum mixing proportion of different sizes of PP fibers was discussed. The results indicated that the multi-scale polypropylene fiber reinforced concrete (dropped with three different sizes of PP fibers into concrete) had the best positive hybrid effect on resisting to high temperature, when the total PP fiber content was 6 kg/m3 and the macro PP fiber substitution was 80%. Meanwhile, the addition of macro PP fibers significantly enhanced the toughness of concrete. Compared with the value of plain concrete, the compressive and splitting tensile strength of the optimal multi-scale polypropylene fiber reinforced concrete at 800 °C increased 14% and 36% respectively.

Mechanical Properties of Polypropylene Fiber Concrete after High Temperature

2014 ◽  
Vol 662 ◽  
pp. 24-28 ◽  
Author(s):  
Xi Du ◽  
You Liang Chen ◽  
Yu Chen Li ◽  
Da Xiang Nie ◽  
Ji Huang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Polypropylene Fiber ◽  
Plain Concrete ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Fiber Concrete ◽  
Compressive Strength Of Concrete ◽  
Polypropylene Fiber Reinforced Concrete

With cooling tests on polypropylene fiber reinforced concrete and plain concrete that were initially subjected to different heating temperatures, the change of mechanical properties including mass loss, uniaxial compressive strength and microstructure were analyzed. The results show that the compressive strength of concrete tend to decrease with an increase in temperature. After experiencing high temperatures, the internal fibers of the polypropylene fiber reinforced concrete melted and left a large number of voids in it, thereby deteriorating the mechanical properties of concrete.

The influence of elevated temperatures on the mechanical properties of polypropylene fiber reinforced concrete

2017 ◽  
Vol 3 (3) ◽  
pp. 116
Author(s):  
Majid Atashafrazeh ◽  
Ahmet Ferhat Bingöl ◽  
Murat Caf
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Elevated Temperatures ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Strength Increase ◽  
Fiber Reinforced ◽  
Wool Fibers ◽  
Polypropylene Fiber Reinforced Concrete ◽  
Temperature Melting

This paper describes the strength of Polypropylene Fiber Reinforced Concrete (PFRC) exposed to the elevated temperatures. In the study, control specimens without any fibers and the concrete specimens with the ratios of 0.30, 0.60, 0.90 and 1.20 kg/m³ polypropylene fibers both in woolen and bar shape fiber have been produced. The specimens have been kept in the laboratory conditions for 28 days. Shortly after the curing period was completed, every group was heated at 23, 150, 300, 450, 600 and 750°C for two hours then the compressive strengths of them were determined. The maximum compressive strength was obtained by the specimens including 0.30 kg/m³ woolen polypropylene. For this group, the compressive strength increase was 8% according to the control specimens. The compressive strengths of bar polypropylene fiber concrete were higher than the wool fibers under elevated temperatures. On the other hand, more compressive strength values are obtained from the control specimens than fiber groups at 600°C temperature. Melting the polypropylene fiber at 500°C formed some pore spaces in concrete and caused reduction of the compressive strength.

Improved Early-Age Cohesive Stress Response from Hybrid Blends of Micro and Macro Fibers

2021 ◽  
Vol 1046 ◽  
pp. 1-7
Author(s):  
Manjunath V. Bhogone ◽  
Kolluru V.L. Subramaniam
Keyword(s):  
Reinforced Concrete ◽  
Stress Response ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Early Age ◽  
Fiber Reinforced ◽  
Cohesive Stress ◽  
Concrete Matrix ◽  
Polypropylene Fiber Reinforced Concrete

The fracture response of macro polypropylene fiber reinforced concrete (PPFRC) and hybrid blend of macro and micro polypropylene fiber reinforced concrete (HyFRC) are evaluated at 1, 3, 7 and 28 days. There is an improvement in the early-age fracture response of HyFRC compared to PPFRC. The changing cohesive stress-crack separation relationship produced by ageing of the concrete matrix is determined from the fracture test responses. An improved early-age cohesive stress response is obtained from the hybrid blend containing micro and macro fibers. The hybrid fiber blend also has a higher tensile strength at early age when compared to an identical volume fraction of macro polypropylene fibers.

scholarly journals Influence of the Fiber Volume Content on the Durability-Related Properties of Polypropylene-Fiber-Reinforced Concrete

2020 ◽  
Vol 12 (2) ◽  
pp. 549
Author(s):  
Chenfei Wang ◽  
Zixiong Guo ◽  
Ditao Niu
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Volume Content ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Freeze Thaw ◽  
Chloride Environment ◽  
Polypropylene Fiber Reinforced Concrete

Polypropylene-fiber-reinforced concrete impacts the early shrinkage during the plastic stage of concrete, and the fiber volume content influences the durability-related properties of concrete. The purpose of this paper was to investigate the influence of fiber volume content on the mechanical properties, durability, and chloride ion penetration of polypropylene-fiber-reinforced concrete in a chloride environment. Tests were carried out on cubes and cylinders of polypropylene-fiber-reinforced concrete with polypropylene fiber contents ranging from 0% to 0.5%. Extensive data from flexural strength testing, dry–wet testing, deicer frost testing, and chloride penetration testing were recorded and analyzed. The test results show that the addition of the fiber improves the failure form of the concrete specimens, and 0.1% fiber content maximizes the compactness of the concrete. The flexural strength of specimen C2 with 0.1% fiber shows the highest strength obtained herein after freeze–thaw cycling, and the water absorption of specimen C2 is also the lowest after dry–wet cycling. The results also indicate that increasing the fiber volume content improves the freeze–thaw resistance of the concrete in a chloride environment. Chlorine ions migrate with the moisture during dry–wet and freeze–thaw cycling. The chlorine ion diffusion coefficient (Dcl) increases with increasing fiber content, except for that of specimen C2 in a chloride environment. The Dcl during freeze–thaw cycling is much higher than that during dry–wet cycling.

DURABILITY PERFORMANCE AND DIMENSIONAL STABILITY OF POLYPROPYLENE FIBER REINFORCED CONCRETE

2018 ◽  
Vol 13 (2) ◽  
pp. 20-41 ◽  
Author(s):  
Ali Mardani-Aghabaglou ◽  
Süleyman Özen ◽  
Muhammet Gökhan Altun
Keyword(s):  
Reinforced Concrete ◽  
Dimensional Stability ◽  
Polypropylene Fiber ◽  
Pulse Velocity ◽  
Fiber Reinforced Concrete ◽  
Concrete Mixture ◽  
Fiber Reinforced ◽  
Concrete Mixtures ◽  
Durability Performance ◽  
Polypropylene Fiber Reinforced Concrete

In this study, the durability performance and dimensional stability of polypropylene fiber reinforced concrete mixture were investigated. For this purpose, two series of concrete mixtures, including a 0.45 water/cement ratio was prepared both in the absence and presence of fiber. A CEMI 42.5 R type portland cement and crushed limestone aggregate with a maximum particle size of 25 mm were used. In addition to the control mixture without fiber, three different concrete mixtures were prepared by adding polypropylene fiber as 0.4%, 0.8% and 1% of total volume into the mixture. The time-dependent fresh state properties, strength, ultrasonic pulse velocity, transport properties, drying shrinkage and freeze-thaw resistance of concrete mixtures, sodium sulfate attack and abrasion were investigated comparatively. Test results demonstrated that utilization of fiber affected the fresh properties of the concrete mixtures negatively. However, the 0.8% fiber-bearing mixture showed the highest performance in terms of durability and dimensional stability. Beyond this utilization ratio, the durability performance of the concrete mixture was negatively affected. The risk of nonhomogeneous dispersion of the fiber in the mixture was relatively high in the excess fiber-bearing mixture. Consequently, with the formation of flocculation in the mixture the void ratio of concrete mixture increased.

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