Rheological Properties And Experimental Study Of Bamboo Fiber Self-compacting Concrete

Self-compacting concrete is a kind of high performance concrete with great application potential,which is widely used in thin-walled structures and dense reinforcement structures because of its good fluidity,good durability and environmental friendleness.Bamboo fiber is extracted from bamboo,which has the characteristics of easy availability of raw materials,low production cost and environmental friendliness.At the same time,it has good toughness,strong plasticity,good tensile properties and other mechanical properties.Combined with concrete,it can improve the corrosion resistance of ordinary concrete and crack resistance,etc.,is one of the current research hotspot of scholars both-at home-and-abroad.In thesis,a reasonable mix ratio of self-compacting concrete is selected and bamboo fibers of different volume ratios and lengths are added to prepare bamboo fiber self-compacting concrete.By means of mechanical experiment and numerical simulation,Experimental exploration and theoretical analysis of the rheological properties of the clean pulp and bamboo fiber self-compacting concrete slurry,as well as the hardening of the material specimens under compressive,tensile,bending and fatigue resistance,combined with numerical simulation for theoretical analysis.The following results are obtained:(1)The fluidity and rheological properties of bamboo fiber self-compacting concrete are tested respectively.The experimental results show that the slump of bamboo fiber concrete decreases with the increase of the volume ratio of bamboo fiber.The shear yield limit of bamboo fiber reinforced concrete increases with the addition of fiber.(2)Compared with plain concrete,the compressive strength of bamboo fiber concrete is slightly decreased,but the tensile strength of bamboo fiber concrete is obviously increased.When the fiber volume ratio is 1%and the fiber length is 30 mm,the tensile resistance is improved by 40%.The bending strength of concrete increases with the increase of bamboo fiber length,and increases first and then decreases with the increase of bamboo fiber volume.When the fiber length is 40mm and the content is 1%,the bending strength of concrete reaches the highest value of 4.34MPa.In the bending test,the addition of bamboo fiber did not increase the ultimate bending strength of concrete specimens.However,when bamboo fiber concrete reaches the ultimate stress,although there are micro cracks in the specimen,it can still withstand the tensile stress through the presence of bamboo fiber,so that bamboo fiber concrete can continue to work until the specimen is destroyed.It shows that bamboo fiber inhibits the development of microcracks and increases the toughness of concrete.(3)Through the flexural fatigue test of bamboo fiber reinforced concrete specimens under constant amplitude cyclic load,the deformation fatigue curves of bamboo fiber reinforced concrete members with different dosage were obtained.By comparing the test data,the results show that the strain development process of the test sample can be roughly divided into three stages,which are:the stage of rapid strain growth,the stage of uniform strain growth,and the stage of rapid strain growth.In the fatigue test of bamboo fiber concrete with different lengths and contents,the fatigue life of plain concrete specimen is the minimum,and the fatigue life of concrete specimen is the maximum when the volume percentage of bamboo fiber is 2%and the length is 40mm,which verifies that bamboo fiber inhibits the expansion of microcracks of specimen,thus improving its fatigue toughness.(4)ABAQUS software is employ the compressive strength,splitting tensile strength and bending strength of bamboo fiber concrete specimens.The simulated results are in good agreement with the experimental results.Bamboo fiber can increase the maximum compressive strain of concrete specimens and improve the splitting tensile strength of concrete.