Dynamic Compressive Behavior of Polyethylene Fiber Reinforced High Strength and High Ductility Concrete over Wide Ranges of Strain Rate

High strength and high ductility concrete (HSHDC) possesses extraordinary mechanical proper-ties, including high compressive strength (123.3 MPa), high tensile strength (9.1 MPa), and ideal tensile strain capacity (6.6%), and exhibits promising application prospects in structures against dynamic loadings. This study systematically explored the dynamic compressive behavior of Polyethylene (PE) fiber reinforced HSHDC over wide ranges of strain rates (10- 5-102 s-1) using the hydraulic servo-controlled testing machine and split Hopkinson pressure bar device. The dynamic stress-strain relations and failure patterns of HSHDC were obtained, based on which the dynamic compressive strength, peak compressive strain, and specific energy absorption (SEA) were analyzed in detail. It indicated that the compressive strength increased moderately at low strain rates (2.4 x 10- 5-2.4 x 10-2 s- 1) and obviously at high strain rates (105.8-258.8 s-1) with the increase of strain rate. To describe the dynamic compressive strength, several dynamic in-crease factor (DIF) formulae in the literature were evaluated, and an experimentally fitted DIF formula was proposed. The peak compressive strain remained almost constant at low strain rates, while it decreased significantly with the increase of strain rate at high strain rates. Besides, the dynamic SEA shows a bilinear growth law with the increasing strain rate and has a more obvious strain rate effect than the dynamic compressive strength. Finally, a nonlinear viscoelastic constitutive model was established, which satisfactorily predicts the compressive stress-strain relationship of HSHDC at different strain rates.