Abstract
In recent years, the application of engineered cementitious composites (ECCs) in structures subjected to cyclic fatigue loading, such as highway bridges, has gained widespread attention. However, most existing ECCs do not have sufficient strength and ductility, which limits their applications, especially in highway bridge structures under high-stress. In this work, an ultra-high performance engineered cementitious composite (UHP-ECC) was configured, which had a compressive strength of approximately 120 MPa, a tensile strength of up to 12 MPa, and a tensile strain capacity of more than 8%. This paper presents a study of the fatigue performance of UHP-ECC at four different fatigue stress levels through the four-point bending test. The mid-span deflection of the specimen was monitored along with the crack opening displacement (COD) of the pure bending section at the bottom of the specimen, and the crack width. In addition, the dissipated energy was calculated at various stress levels. The progressive formation of cracks under static loading was monitored using the digital image correlation (DIC) technique. The fibers at the fractured surface of the specimens were observed and analyzed by environmental scanning electron microscopy, and the morphology of the fibers was obtained at different fatigue stress levels. Eventually, the fatigue life under different stress levels was obtained, and the relationship between the fatigue life and the stress level was established.
Highlights
The engineered cementitious composite (ECC) is fiber reinforced and designed using micromechanical principles, which shows high ductility under uniaxial tensile and shear stress [1].The engineered cementitious composites (ECCs) enters the plastic deformation stage after the initial cracks are generated
After 2 million fatigue loading cycles at a stress level of 0.5 without failure, the ultra-high performance engineered cementitious composite (UHP-ECC) specimens were statically reloaded to failure; their flexural behavior was compared to that of the UHP-ECC specimen, which was directly statically loaded to failure
The UHP-ECC specimens were subjected to fatigue tests under different fatigue loading stresses
Summary
The engineered cementitious composite (ECC) is fiber reinforced and designed using micromechanical principles, which shows high ductility under uniaxial tensile and shear stress [1]. The ECC enters the plastic deformation stage after the initial cracks are generated. The strain-hardening process is accompanied by the continuous generation and development of micro-cracks. The ultimate tensile strain capacity of the conventional polyvinyl alcohol fiber ECC (PVA-ECC) exceeds 3%, which is 200 times that of concrete [2]. The crack width of ECCs falls within a reasonable range due to the constraint of the maximum bridging stress. Even during the stage where saturated multiple cracks are formed, the maximum crack width of PVA-ECCs can be maintained below 100 μm [3]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have