Abstract

The fiber length has a significant impact on the fiber bridging capacity and the mechanical properties of high ductility cementitious composites (HDCCs), which is related to fiber/matrix interfacial bonding. However, this fundamental knowledge of HDCCs design has rarely been investigated systematically. To this end, this study deeply investigates the effect of the fiber length on the bridging stress and the complementary energy with various fiber/matrix interfacial bonds in theory. Then, the mechanical performances of HDCCs with various fiber lengths and compressive strengths were evaluated experimentally. In micromechanical design, longer fibers can achieve stronger bridging stress and more sufficient complementary energy regardless of the fiber/matrix interfacial bonding properties. However, it should be noted that the increase in bridging capacity was quite slow for the overlong fibers and excessive interfacial bonding. The experiments indicated that overlong fibers (18 mm and 24 mm) easily twined on the mixer blade and were hard to disperse evenly. The HDCCs with shorter fibers displayed better workability. The compressive strength was less affected by the fiber length, and most striking differences were less than 5.0%, while the flexural properties and the tensile properties first increased and then decreased when the fiber length ranged from 6 mm to 24 mm. Consequently, the fibers with lengths of 9 mm and the fibers with lengths of 12 mm were better candidates for the HDCCs with compressive strengths of 30 MPa to 80 MPa, and fibers with lengths of 9 mm caused the HDCCs to exhibit higher ductility properties in general.

Highlights

  • High ductility cementitious composites (HDCCs) are a special kind of civil engineering materials that have attracted increasing interest in recent years due to their high tensile strain and robust strain hardening behaviour

  • The excellent crack control ability of HDCCs features the characteristics of multiple cracks rather than a localized crack, and the typical crack width is generally less than 100 μm [1,2,3,4,5]. e unique mechanical properties of HDCCs materials overcome the weaknesses in the inherent brittleness and cracking sensitivity of traditional concrete

  • This paper made an in-depth study on the influence of fiber length on fiber bridging capacity and HDCCs properties by combining experimental and theoretical method. e purpose was conducted to tailor the polyvinyl alcohol (PVA) fiber length to achieve better mechanical performance of HDCCs

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Summary

Research Article

E fiber length has a significant impact on the fiber bridging capacity and the mechanical properties of high ductility cementitious composites (HDCCs), which is related to fiber/matrix interfacial bonding. This fundamental knowledge of HDCCs design has rarely been investigated systematically. To this end, this study deeply investigates the effect of the fiber length on the bridging stress and the complementary energy with various fiber/matrix interfacial bonds in theory. En, the mechanical performances of HDCCs with various fiber lengths and compressive strengths were evaluated experimentally. The fibers with lengths of 9 mm and the fibers with lengths of 12 mm were better candidates for the HDCCs with compressive strengths of 30 MPa to 80 MPa, and fibers with lengths of 9 mm caused the HDCCs to exhibit higher ductility properties in general

Introduction
Fiber length Fiber diameter
Fiber bridging stress σ
Aspect ratio
No fiber twining phenomenon
Results and Discussions
Tensile specimen
Uniaxial compression
Full Text
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