动态荷载下聚乙烯醇纤维混凝土阻裂性能试验研究OA北大核心

In order to investigate the effect of fiber volume content on the cracking resistance of polyvinyl alcohol fiber engineered cementitious composite(PVA-ECC)under dynamic loading,impact tests were carried out on the notched semi-circular bending(NSCB)specimen with five fiber volume content(0％,0.75％,1.50％,2.25％,3.00％)by separated Hopkinson pressure rod device(SHPB).Combined with the dynamic fracture process recorded by high speed camera,the dynamic cracking toughness and energy dissipation characteristics of material were analyzed,and the fractal dimension of cracking growth path was calculated according to the theory of box dimension.The results show that the dynamic cracking toughness of material increases first and then decreases with the increase of fiber volume content,and the dynamic cracking toughness is higher when the fiber volume content is in the range of 1.50％to 2.25％.The dissipative energy increases with the increase of fiber content in the range of 0.75％to 2.25％,but the total absorbed energy decreases with the increase of fiber content.Under constant velocity impact,the fractal dimension of final crack growth path after material failure is the highest when the fiber content is 2.25％,and the cracking resistance is best.When the fiber content is more than 2.25％,the fractal dimension of cracking growth path shows a downward trend,and the fiber cracking resistance gain effect decreases.