Comparative study on the dynamic tensile properties of polypropylene and polyethylene fiber reinforced engineered cementitious composites under low to high strain rates

Abstract

In this paper, by adopting the hydraulic direct tensile machine and the Split Hopkinson Tensile Bar (SHTB) apparatus, the direct tensile performances of the fiber reinforced engineered cementitious composites (FRECC) under low to high strain rates (0.0001 s−1 to 135 s−1) were examined with the consideration of different fiber types (polyethylene [PE] and polypropylene [PP] fibers) and fiber contents (1.0 %, 1.5 %, and 2.0 % by volume). The comparison of the direct tensile properties between PP-ECC and PE-ECC was discussed in terms of the failure mode, tensile strength, ultimate strain, and energy absorption. The cost-effective evaluation model was then proposed to assess the feasibility of PP-ECC and PE-ECC in structural application. The comparison revealed that: (1) At low fiber contents, the failure mode of PP-ECC was splitting along the main crack, while PE-ECC exhibited multiple cracks. At high fiber contents, both PP-ECC and PE-ECC performed multiple cracks. (2) Under low strain rates, PP-ECC exhibited a comparable tensile strength to the PE-ECC, and however, PP-ECC performed lower tensile strength than PE-ECC for the same fiber contents at high strain rates. (3) As the strain rates increasing, the ultimate strain of PP-ECC became closer to that of PE-ECC. (4) As fiber contents increased, the difference in the energy absorption between the PP-ECC and PE-ECC got smaller. (5) Based on the cost-effective evaluation, when the fiber content was 1 %, the PE fiber showed better mechanical and economic benefits than the PP fiber for use in structural applications under varied strain rates. However, when the fiber content was beyond 1 % (i.e. 1.5 % and 2 %), adopting the PP fiber in the FRECC performed a better cost-effective solution for structural application under high strain rates.