Research on Tensile Softening Constitutive Relation of Macro Polypropylene Fiber Reinforced Concrete

LIU Jinhui; LIU Xiaolong; LIU Tao; DONG Wei

doi:10.3724/j.gyjzG23091904

Volume 54 Issue 5

May 2024

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LIU Jinhui, LIU Xiaolong, LIU Tao, DONG Wei. Research on Tensile Softening Constitutive Relation of Macro Polypropylene Fiber Reinforced Concrete[J]. INDUSTRIAL CONSTRUCTION, 2024, 54(5): 220-225. doi: 10.3724/j.gyjzG23091904

Citation:

LIU Jinhui, LIU Xiaolong, LIU Tao, DONG Wei. Research on Tensile Softening Constitutive Relation of Macro Polypropylene Fiber Reinforced Concrete[J]. INDUSTRIAL CONSTRUCTION, 2024, 54(5): 220-225. doi: 10.3724/j.gyjzG23091904

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Research on Tensile Softening Constitutive Relation of Macro Polypropylene Fiber Reinforced Concrete

doi: 10.3724/j.gyjzG23091904

1. Dalian Power Supply Company, State Grid Liaoning Electric Power Co., Ltd., Dalian 116001, China;
2. Faculty of Construction Engineering, Dalian University of Technology, Dalian 116024, China

Received Date: 2023-09-19
Available Online: 2024-06-22

Abstract

Abstract

In order to reveal strengthening and toughening mechanisms of the macro polypropylene fiber reinforced concrete, the tensile softening constitutive relation of the macro polypropylene fiber reinforced concrete was investigated. Three fiber lengths, i.e. 20 mm, 30 mm and 40 mm, and three mass contents, i.e. 0.13%, 0.17% and 0.21%, were selected. Mechanical and fracture properties of the macro polypropylene fiber reinforced concrete, i.e. tensile strength, initial cracking load, and the maximum load, were studied by the splitting tensile test and the three-point bending fracture test, and the tensile softening constitutive relation was derived by the improved J-integral method. The results showed that the cohesive stress decreased rapidly with the increase of the crack opening displacement. Compared with the ordinary concrete, the stress free opening displacement of the macro polypropylene fiber reinforced concrete significantly increased and the fracture process zone length significantly increased, indicating that the brittleness degree significantly reduced. According to the simplified method recommended by Wittmann, a bilinear softening curve for the macro polypropylene fiber reinforced concrete was proposed, in which the cohesive stress at the turning point σ_s = 0.135f_t, the crack opening displacement at the turning point w_s = 0.054G_f/f_t, and the stress free opening displacement w₀ = 14.417G_f/f_t. With the increase of fiber length and mass content, the stress free opening displacement w₀ significantly increased, indicating that the brittleness degree significantly decreased.
- macro polypropylene fiber,
- concrete,
- tensile softening constitutive relation,
- fiber length,
- mass content

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References(15)

References

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