Experimental Study On Dynamic Mechanical Properties Of Natural Fiber Reinforced Concrete

Natural fiber(bamboo fiber and jute fiber)reinforced concrete is a geotechnical building material formed by cementation,coarse aggregate,fine aggregate and evenly distributed natural plant fiber through hydration reaction.It not only has the advantages of environmental protection,energy saving and low price,but also has the performance of cushioning energy absorption and strengthening the toughness of concrete structure.It is a green building material that can be vigorously developed.This paper focuses on the feasibility and necessity of applying bamboo fiber and jute fiber concrete to practical projects,and briefly introduces the history,progress and current situation of research on mechanical properties of natural fiber concrete.The experimental principle of SHPB impact compression and dynamic splitting test method selected in this paper is briefly described.Quasi-static compression,splitting,impact compression and dynamic splitting tests were carried out on jute fiber reinforced concrete with volume fraction of 0.5%,1.0%,1.5%,2.0% and bamboo fiber reinforced concrete with volume fraction of 0.5%,1.5%and 2.5%,respectively.The main mechanical parameters of bamboo fiber concrete and jute fiber concrete under two types of tests,such as compressive strength,dynamic enhancement factor,peak strain,toughness index,splitting strength,energy dissipation,tension and compression ratio,etc.were obtained for each test supplemented with plain concrete as the control group.By analyzing the relationship between these parameters and strain rate,some parameters such as dynamic enhancement factor and toughness index were fitted to obtain relevant empirical formulas.Then the effects of fiber type and content on the mechanical properties of concrete were discussed.The conclusion of this experiment is that in dynamic compressive test,in a very limited range of strength reduction,fiber improves the energy absorption effect of concrete,and both kinds of fiber reinforced concrete have the best energy absorption effect with the fiber volume content of 1.5%,and the strength reduction is the least,which reflects the effect of toughening;in dynamic splitting,the strength of bamboo fiber reinforced concrete decreases somewhat,and jute fiber reinforced concrete increases,while the total energy dissipation of both kinds of fiber reinforced concrete is higher than that of plain concrete.And both of them improve the dynamic tension-compression ratio,reflecting the effect of strengthening and toughening.