海水干湿循环作用下UHTCC动态压缩性能试验研究OA北大核心CSTPCD

To study the effects of the strain rate and the seawater dry-wet cycle on the dynamic compression performance of ultra-high toughness cementitious composites(UHTCC),a separate Hopkinson pressure rod system with a diameter of 75 mm was used to carry out dynamic compression tests on UHTCC after 0 to 120 d of the seawater dry-wet cycle.An UHTCC dynamic constitutive model considering the seawater dry-wet cycle was proposed by improving the ZWT nonlinear viscoelastic constitutive model.The results show that the dy-namic compressive strength increase factor of UHTCC decreases with the increase of the dry-wet cycle.Under the same impact pressure,the peak stress and the energy dissipation of UHTCC first increase and then decrease with the increase of the dry-wet cycle,and reach the peak values at 60 and 90 d,respectively.Under the same dry-wet cycle,the peak stress,the dynamic compressive strength increase factor and the energy dissipation of UHTCC increase with the increase of strain rate,showing obvious strain rate effect.The improved dynamic constitutive model can describe the dynamic compressive stress-strain relationship of UHTCC under the seawa-ter dry-wet cycle.