Experimental Study On Mechanical Properties Of Bamboo Fiber Reinforced Concrete

Bamboo fiber concrete is a kind of fiber concrete. The properties of bamboo fiber concrete are multiple, including the properties of inorganic and organic materials. Cement is a kind of brittle material, when combined into concrete with cement and other materials, the shape of the component easily deformed contraction,the weight become bigger, the toughness is poor, the tensile strength is low, easy to crack after forming. These characteristics make people have scruples in project application. we use the light weight, good elasticity, excellent toughness, high tensile strength, easy production processing, low carbon environmental protection features of bamboo fiber injection into concrete, to construct a new type of low carbon environmental protection material bamboo fiber reinforced concrete. Adding bamboo fiber to concrete will play a role in supporting aggregate, bamboo fiber concrete can withstand the tensile stress generated during the hardening stage and reduce the crack size and quantity of concrete directly. In this paper, the bamboo fiber is added to the reinforced concrete, that is, the structure of the bamboo fiber reinforced concrete structure.First, experiment of the concrete slump testing, reinforcement tensile testing, concrete cube compressive testing and material testing is carried,then according to the theory of scale model,to select the similar material and design the similar model.Normal section and oblique section bending is tested. Research and comparison bending deformation ability, development patterns, failure characteristics of bamboo fiber reinforced concrete beam. The main theoretical results and scientific research results are as follows:(1) Considering the effects of length diameter ratio of bamboo fiber, the selected two groups are the same, and suitable for the long diameter ratio of bamboo fiber were tested, the effects of different volume ratio of bamboo fibers on the test were also compared. The bamboo fibers with different volume ratio were divided into three groups with the same length and diameter,another long diameter ratio, but the volume ratio of bamboo fiber is also three groups,so the experiment group a total of six groups, no fiber content as a blank control group.(2) Because beam test is more, so the test using scale model to design the dimensions of the cross-section of the beam.In scale model test, the similarity between the model and the prototype is directly related to the accuracy of the prototype.The similar conditions of similar loads is often difficult in scale model test design.The scale model selection will largely determine the accuracy and precision of test data, design optimization scheme based on similar conditions.Selecting the suitable length width height ratio and seting the mode of loading,trial should stress to obtain the precise numerical determined scale for one-third of, that is, the test scheme is selected as the prototype to reduce the size of the third one.(3) Using the strength of bamboo fiber reinforced concrete beam tested before to concrete mix design.Bamboo fiber reinforced concrete beams are tested after the calculation of the normal section of the bamboo fiber reinforced concrete beam, including concrete slump test, steel bar tension test,concrete cube compressive strength test. Providing original basic data for bending test and cross section bending test of bamboo fiber reinforced concrete beams.(4) Positive cross section beam and curved beam with cross section each have 7,altogether 14. Both of these use the symmetric concentrated load system,detect of the function of each load after load:(1)Crack spacing,(2).crack width,(3)deflection,(4)strain of steel bar,(5)concrete strain.Observing and studying the development shape, deformation capacity, damage characteristics, crack number, crack width, etc of positive cross section beam and curved beam with cross section.(5) Reinforced concrete with bamboo fiber longitudinal reinforcement to the concrete binding can be good, made a third of bamboo fiber and concrete and longitudinal bars are fully integrated, complement each other, play their own advantages, the cracks appeared late, shorter length, and the number of less. The compressive strength of the reinforced concrete with bamboo fiber is higher, and the ductility and ductility are improved. When the crack develops and extends, the bamboo fiber has obvious control effect on it.(6) Bamboo fiber reinforced concrete cross section bending test as the load increased, the cracks began to develop to the point of loading and bearing.the main cracks continued to spread began to increase slowly,diagonal cracks are also beginning to appear in the designated area,when the load is gradually increasing, the main crack and the diagonal cracks begin to meet,but in order to prevent local pressure from local damage,the bamboo fiber reinforced concrete beam is loaded with a steel pad,so in the local stress state, the loading point of the two ends of the bamboo fiber reinforced concrete beam is not completely crack extension,in the diagonal crack with the increase of load also began to increase, and showing a state of "eight", the appearance and development of crack stability rules.When the main crack occurs, the gap is larger and the bamboo fiber can be seen through the cracks,the deflection value of bamboo fiber reinforced concrete beam in the middle of the limit load is increased rapidly,bamboo fiber, reinforced concrete, three from the initial combination now began to fall apart, finally completely unable to bond,Bamboo fiber reinforced concrete beams in the ultimate load is completely lost when the carrying capacity, the load will be a short period of time to stabilize, and then quickly dropped to the initial value.(7) The effect of bamboo fiber on the ultimate load is the process of increasing the load of each level, the bamboo fiber will absorb and bear the load.Even if the invisible cracks or the visible cracks, bamboo fibers can delay the development of cracks, and sometimes even hinder the occurrence of cracks.However ordinary reinforced concrete beams have not joined the bamboo fiber, the occurrence and development of cracks will become relatively rapid.The internal force redistribution of the test beam is improved, and the internal force redistribution is more stable and adequate.(8) The occurrence and development of both bending cracks and diagonal cracks are very stable and adequate When the bamboo fiber reinforced concrete beam is completely lost.In the vicinity of the neutral axis, the height of the vertical crack is relatively high,Some have even exceeded the height of the neutral axis,all the bamboo fiber reinforced concrete beams are destroyed by shear and compression.(9) Through the establishment of ANSYS numerical analysis model,analysis of stress, strain and displacement of bamboo fiber reinforced concrete flexural test by numerical simulation method,Compared with the corresponding experimental results.