Abstract
To explore the effect of multi-scale polypropylene fiber (PPF) hybridization on the mechanical properties of roller-compacted concrete (RCC), the early-age (3, 7, 14, 28 days) compressive strength, splitting tensile strength and uniaxial tensile test of RCC reinforced with micro-, macro- and hybrid polypropylene fibers were investigated. Then, the tensile stress–strain curve of polypropylene fiber-reinforced roller-compacted concrete (PFRCC) and the corresponding tensile parameters were obtained. The uniaxial tensile constitutive equation of PFRCC and fiber hybrid effect function was also proposed. Finally, the enhancement mechanism of fiber hybridization on mechanical properties of RCC was analyzed. The results indicated that the strength and toughness of PFRCC improved with the incorporation of PPF, showing obvious plastic failure characteristics of PFRCC. Before curing the concrete for 7 days, micro-PPF played a major role in strengthening RCC, while macro-PPF played a major role in reinforcing concrete after that. Moreover, the tensile strength and toughness indexes of multi-scale PFRCC performed the best, indicating the positive hybridization of three types of PPF. The proposed PFRCC uniaxial tensile constitutive equation and fiber hybrid effect function based on existing researches were also well matched with the experimental results.
Highlights
Roller-compacted concrete (RCC) is commonly used in a variety of road pavements, pavement bases and et al (Lopez-Uceda et al, 2016), which is known for saving cement, early high strength and reducing construction time
The addition of macro-polypropylene fiber (PPF) maintained the integrity of polypropylene fiber-reinforced roller-compacted concrete (PFRCC) A3 ~ A8 specimens and improved the compressive toughness of rollercompacted concrete (RCC)
4 Conclusions Through the above research on the effect of hybrid effect of polypropylene fibers on the compressive strength, splitting tensile strength and axial tensile properties of RCC, the main conclusions can be summarized as follows: (1) The addition of micro-PPF had a significant effect on the compressive and splitting tensile strength of RCC within 7 days, and the addition of macro-PPF played a major role in RCC after curing for 7 days
Summary
Roller-compacted concrete (RCC) is commonly used in a variety of road pavements, pavement bases and et al (Lopez-Uceda et al, 2016), which is known for saving cement, early high strength and reducing construction time. RCC includes some disadvantages, such as low tensile strength, poor crack resistance and toughness, limiting its development in engineering structures (Bayagoob & Bamaga, 2019; Lam et al, 2018). Previous studies (Ahmad & Umar, 2018; Benouadah et al., 2017; Marushchak et al, 2019; Yoo & Banthia, 2016) have shown that the addition of fibers can effectively control the formation and development of cracks in concrete, and greatly increase the strength and toughness of concrete. Steel fiber has high elastic modulus and stiffness, which is widely used for its good strengthening and toughening effect on concrete. Its development is limited by its deficiencies of high cost, poor corrosion resistance and inconvenient construction.
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