Effect of carbon nanotubes on shear behavior of PVA-ECC beams

초록

This study experimentally verified the effect of adding carbon nanotubes (CNTs) on the shear behavior of polyvinyl alcohol-engineered cementitious composites (PVA-ECC) beams without shear reinforcement at different longitudinal reinforcement ratios and shear span-to-depth (a/d) ratios. The test results indicated that CNTs addition significantly enhanced the shear capacity, showing an improvement of up to 15 % in tests with a variable longitudinal reinforcement ratio and up to 33 % in tests with a variable shear span-to-depth ratio. Furthermore, in load-deflection responses, the initial stiffness increased for all variables due to CNTs addition. However, the test results of some specimens indicated that CNTs addition increased the uncertainty associated with the material properties of PVA-ECC. The uncertainty is considered to require incorporation into safety factors in the design process through further research. The test results were compared with the shear capacities predicted by fib Model Code 10 (MC10), fib Model Code 20 (MC20), and the equations proposed in previous studies. The investigation revealed that MC20 showed the most reasonable prediction in this study.

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