Influence of strain rate and fiber blend mode on the tensile behaviors of steel-polyethylene hybrid fiber reinforced engineered cementitious composites
Liang Li, Zhengpeng Li, Jun Wu, Tangjun Li, Xiuli Du
Abstract
In order to study the static and direct dynamic tensile behaviors of steel-polyethylene hybrid fiber reinforced engineered cementitious composites (ST/PE-HFRECC), tests were conducted using a static test machine and the split Hopkinson tension bar (SHTB), respectively. The influence factors of interest in the study included the blend ratio of steel and polyethylene fibers in the ST/PE-HFRECC (Total fiber content is 2 %.), the strain rate (Range: 10 −5 s −1 - 100 s −1 ). The conclusions are as follows: (1) Increasing the polyethylene fiber content increases the static ductility of ST/PE-HFRECC. Increasing the steel fiber content causes its static brittle damage. Static ductility of polyethylene fiber reinforcement is superior to that of steel fibers. (2) The tensile strength , ultimate strain, energy absorption, and dynamic increase factor of ST/PE-HFRECC exhibit strain rate enhancement effect. Increased strain rate changes the damage state from multi-seam to main seam cracking. PE fibers increase strength and toughness better than steel fibers at different strain rates. (3) Increased polyethylene fiber content results in a more obvious strain-hardening effect and an increase in ultimate strain for ST/PE-HFRECC. 1.5 % or more polyethylene fibers increase the sensitivity of its tensile strength to strain rate. (4) The optimum fiber mixing ratio of ST/PE-HFRECC at various strain rates is different. Therefore, the correct fiber mixing method that matches the engineering application demand is important.