Application Study of Polypropylene Fiber Reinforced Concrete Railway Tunnel Lining Structure within Hard Rock Mass Using Wet-Sprayed Technique

2009 ◽  
Vol 610-613 ◽  
pp. 76-80
Author(s):  
Tai Quan Zhou ◽  
Yuan Hua
Keyword(s):  
Rock Mass ◽  
Reinforced Concrete ◽  
Polypropylene Fiber ◽  
Tunnel Lining ◽  
Fiber Reinforced Concrete ◽  
Railway Tunnel ◽  
Sprayed Concrete ◽  
Rock Mass Stability ◽  
Lining Structure ◽  
Polypropylene Fiber Reinforced Concrete

The wet sprayed concrete technique has good virtue of improving the working condition within the tunnel, fewer reflective concrete loss and higher sprayed concrete quality. The concrete mixed with polypropylene fiber could improve the concrete inner structure, the flexural strength, tensile strength and anti-penetrating ability. The application of the wet sprayed polypropylene fiber reinforced concrete in the construction of tunnel lining structure could improve the stability of tunnel rock mass. The nonlinear finite element analysis is performed on rock mass stability of the railway tunnel lining structure and the rock mass stability is analyzed both for the un-lining tunnel and the lining tunnel. The computation result shows that the rock mass plasticity zone distribution with the lining structure is fewer than that without lining structure. To measure the deformation behavior, tunnel deformation measurement sensors are installed in the railway tunnel transverse section. The measured railway tunnel deformation result also shows that the lining structure deforms little and the rockmass is in stable state.

Early Stage Tunnel Lining Experimental Study of Jinhuashan Railway Tunnel Construction within Soft and Weak Rock Mass

2012 ◽  
Vol 204-208 ◽  
pp. 1532-1537
Author(s):  
Li Qiao Jin ◽  
Tai Quan Zhou ◽  
Bao Hua Lv
Keyword(s):  
Rock Mass ◽  
Reinforced Concrete ◽  
Early Stage ◽  
Tunnel Lining ◽  
Fiber Reinforced Concrete ◽  
Concrete Lining ◽  
Fiber Reinforced ◽  
Railway Tunnel ◽  
Tunnel Section ◽  
Lining Structure

Polypropylene fiber reinforced concrete can improve the common concrete flexibility and it is beneficial for interaction between concrete lining structure and rock mass. The use of fiber reinforced concrete with wet sprayed concrete technique can improve the concrete lining structure construction quality and improve the rock mass self-bearing capacity. The wet-sprayed fiber reinforced concrete is first introduced in Jinhuashan railway tunnel early stage lining structure within soft and weak rock mass. The design of Jinhuashan railway tunnel lining structure using fiber reinforced concrete is introduced and the requirement of material used is explained. To evaluate the lining effect using wet-sprayed fiber reinforced concrete, the online monitoring method is used to measure the rock mass pressure and the concrete lining layer stress for both the experimental tunnel sections and comparison tunnel section. The monitoring data result shows that the rock mass pressure in experimental section is even distribution with lower rock mass pressure and lower concrete lining layer stress. The value of rock mass pressure and tunnel lining layer stress in comparison tunnel section is a little higher than that in experimental tunnel section. The experimental tunnel section using fiber reinforced concrete has good lining effect.

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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