Flexural fatigue behaviour of steel reinforced PVA-ECC beams

摘要

This paper presents an experimental investigation of the flexural fatigue behaviour of steel reinforced polyvinyl alcohol-engineered cementitious composite (PVA-ECC) beams. The influence of the PVA-ECC matrix and stirrups on the fatigue strength of steel reinforced beams was studied. Eleven beams, including three steel reinforced normal concrete beams (RC beams), four reinforced PVA-ECC beams with stirrups (RECC beams) and four reinforced PVA-ECC beams without stirrups (RECC-NS beams), were tested under a constant amplitude cyclic loading. The minimum load of each cycle was set at 20% of the static strength of the corresponding beam while the maximum loads ranged from 60% to 90%. Experimental results showed that the RC and RECC beams exhibited flexural failure with fracture of tensile reinforcement bars. By contrast, RECC-NS beams tested under 20-90%, 20-70% and 20-60% load ranges were respectively failed by shear, combined of shear and flexural, and flexural with tensile reinforcement bars yielded. The test results showed that the RECC beams generally had shorter fatigue life than the RC beams when tested under relatively high load ranges. This could be due to greater stiffness degradation which eventually led to a higher stress increasing rate in tensile reinforcement bars of the RECC beams. (C) 2019 Elsevier Ltd. All rights reserved.