Stress‐Strain Relation of Steel‐Polypropylene‐Blended Fiber‐Reinforced Concrete under Uniaxial Cyclic Compression

Abstract

This paper investigates the cyclic stress-strain behavior of steel-polypropylene-blended fiber-reinforced concrete (BFRC) under uniaxial cyclic compression. A total of 48 prism specimens were tested for different fiber volume fractions and aspect ratios. The results show that the introduction of blended fibers has synergetic effects on improving the cyclic behavior of concrete in terms of peak strength, postpeak ductility, hysteretic energy dissipation, and stiffness degradation. Moreover, the increase in the volume fractions of both steel and polypropylene fibers can lead to a remarkable decrease in plastic strain accumulation. Furthermore, the stiffness degradation ratio as well as the stress deterioration ratio of BFRC can be significantly alleviated in comparison with those of plain concrete, notwithstanding that the degradation amount is insensitive to the variations of fiber parameters. Subsequently, based on the test results, a constitutive model is developed to generalize the cyclic stress-strain responses of BFRC, with the contributions of blended fibers taken into account. The developed model is then verified by independent experimental results and other test data reported in the literature. It is observed that the prediction yields a close estimation of the cyclic compressive behavior of BFRC with varying fiber parameters.

Multiscale Geomechanical Behavior of Fiber-Reinforced Cementitious Composites Under Cyclic Loading Conditions—A Review

“…Correspondingly, the peak point B (Figure 1) is followed by a noticeable stress drop with distinguished unloading and reloading paths that highlight the hysteretic behavior of FRCC under cyclic tensile loading (Boulekbache et al, 2016). However, in the post-peak region (paths CD and DE in Figure 1), fiber sliding, and pull-out mechanisms are the main contributors to the energy dissipation capacity of FRCC, which causes more defined hysteretic loops with increasing load cycles (Xu et al, 2018a). Conversely, the sudden drop after the peak stress is associated with the fracturing of the cementitious matrix.…”

“…The envelope curve, usually referenced as the upper boundary of the cyclic response, can be used to analyze the constitutive behavior of FRCC under cyclic compressive loading (Xu et al, 2018a). Specifically, the deviation of the envelope stress-strain curve from the monotonic envelope could be an important mechanical characteristic of FRCC's post-peak behavior.…”

“…The inconsistent cyclic and monotonic envelop curves in the post-peak stage can be attributed to the strengthened multiple-cracking characteristic of FRCC under cyclic compressive loading (Nataraja et al, 1999;Krahl et al, 2019). Specifically, this multiple cracking process results in significant microscale damage accumulation and macroscale stress deterioration (Li et al, 2017;Xu et al, 2018a). Consequently, fiber reinforcement is able to yield different damage and post-peak (softening or hardening) mechanisms responsible for the macroscale mechanical response under monotonic and/or cyclic loadings (Krahl et al, 2019).…”

Numerical Simulation of Static Stress‐Strain Relationship and Failure Mode for Freeze‐Thaw Concrete

“…e calibrated CDP model in ABAQUS was used to predict the responses of HFRC materials and structural members subjected to shear and seismic loads [20]. Fourteen (group) parameter values were required for finite analysis based on the CDP constitutive model, while plasticity parameters and stiffness recovery factors have the default values [21] for ordinary concrete (Table 2).…”

Preparation, Performance Test, and Microstructure of Composite Modified Reinforced Concrete

“…e toughness of concrete was improved. Xu et al [27] studied the volumetric content and length-diameter ratio of polypropylene fibers. Compared with ordinary concrete, the failure mode of polypropylene fiber concrete is ductile failure, which significantly improves the compressive toughness and postpeak ductility of concrete.…”