| Basalt Fiber(BF)is a kind of green non-metallic fiber.The research shows that basalt fiber can combine with concrete to form basalt fiber modified concrete,which can improve the brittleness of concrete and the weakness of low tensile strength by virtue of its advantages of good tensile resistance,corrosion resistance,wide range of temperature application and so on.Basalt fiber modified concrete is widely used in modern buildings such as cold,coastal and complicated working environment.At the same time,in order to meet the requirements of modern architecture for construction environment and concrete strength grade,High-strength self-compacting concrete(HSCC)has been widely used in buildings with many problems,such as self-weight of concrete structure,difficulty in vibration after pouring,and difficulty in construction,due to factors such as large span,heavy load and complex structure.Applying BF to HSCC structure can not only improve the strength grade of concrete and reduce self-weight,but also improve the crack resistance and durability of concrete.In practical engineering,reinforced concrete columns are important members under eccentric compression.Therefore,the influence of basalt fiber on eccentric compressive behavior of high-strength self-compacting concrete columns is studied.The following several parts of work have been done:(1)Basalt fiber volume fraction and length were used as experimental parameters to prepare high strength self-compacting concrete modified by basalt fiber with different parameters,and the performance indexes such as relative strength and fluidity were satisfied.(2)The effect of basalt fiber on the performance of high-strength self-compacting concrete column was studied.Five groups of component columns made of concrete with different fiber parameters were respectively subjected to large and small eccentric compression tests to obtain the related stress performance of the basalt fiber modified high-strength self-compacting concrete column,and finally,the damage phenomenon,the cracking load value,the load-strain curves of reinforcing steel bar,the load-strain curve of the concrete,the Mid-span deflection value of the column,ultimate load values and etc.performances recorded during the test were analyzed to comprehensively measure the effect of basalt fibers on the failure patterns,crack resistance,toughness and compressive performance of concrete columns,and to evaluate the influence of fiber length and volume fraction on the eccentric compressive performance of concrete columns.The experimental results show that the addition of basalt fibers can restrain concrete cracking and increase cracking load value in the early stage of loading,at the same time improve the deformability of members,reduce the strain value of concrete when the members reach the ultimate bearing capacity,increase the maximum deflection value of columns,and then increase the ultimate bearing capacity.When the volume content of basalt fibers is 0.1%and the length is 15 mm,the effect of improving the mechanical performance of components is the best.(3)In order to deeply analyze that modification mechanism of the basalt fiber to the stress property of the high-strength self-compacting concrete column,the basalt fiber model was embedded by the method of running the Python script in the ABAQUS software,so that a component finite element model was established to obtain the stress nephograms of steel bar,the concrete and the fiber stress nephograms of the test columns,and the relationship between the Mid-span deflection value and ultimate load values of the column with the volume fraction and length of the fiber.What's more,the simulation results were compared with the experimental results,and the feasibility of the fiber modified component column simulation analysis was verified by the method of embedding the fiber model by running the script,and the optimal parameters of basalt fiber in eccentric compression simulation analysis of the column were obtained. |
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