Study On Preparation And Properties Of Directional Steel Fiber Reinforced Large Flow Concrete

With the continuous rise of centralized mixing,long-distance transportation and pumping,and modern super high-rise buildings,higher requirements are put forward for the fresh mixing performance of traditional concrete.The inherent brittleness of concrete materials further limits the development of modern concrete structures.While ensuring good construction workability,improving the deterioration of brittle failure of concrete structures is an important direction for the development of concrete structures in the future.Large fluid concrete mortar in the premise of meeting the requirements of concrete specifications of fresh performance,with super flow properties,can be well adapted to modern concrete mortar long-distance,high-floor transport conditions,the addition of steel fibers is to further improve the inherent defects of traditional concrete materials.The technology of directional steel fiber reinforced large flow concrete is to add steel fiber and realize orientation on the basis of traditional large flow concrete technology,in order to improve the performance of concrete.Therefore,this paper focuses on the manufacturing process of directional steel fiber reinforced large flow concrete,and makes an in-depth discussion on the basic mechanical properties of oriented components through experimental methods.Firstly,this paper introduces the preparation method of directional steel fiber reinforced large flow concrete,designs the raw materials,matrix mix proportion and fiber content according to relevant specifications,inquires the data,briefly summarizes and introduces the evaluation method of the working performance of large flow concrete,and evaluates the freshness of the concrete matrix prepared in this study by means of experiments.Based on the principle of electromagnetic induction,the steel fiber magnetic field orientation device is made.Through theoretical analysis,the time when the matrix is placed in the magnetic field is roughly determined,and the relevant specimen sizes required for this test are designed.Secondly,in order to better observe the orientation process of steel fiber in the matrix,verify whether the theoretically calculated orientation time can meet the test requirements and whether the orientation effect is good under this set of self-designed orientation test device.Based on the similarity of rheological properties,visualization of orientation process is realized by using the method of preparing transparent concrete substitute by carbomer gel.The orientation effect of steel fiber in the test block is detected based on electromagnetic induction method.The experimental results show that within the theoretical analysis time,the steel fiber in the matrix can basically complete the directional rotation,and it is detected that the inductance increment in the three directions of the disorderly steel fiber concrete specimen is almost the same,and the inductance increment of the directional test block in one direction is much greater than that in the other two directions,which shows that the directional effect of the test pouring test block is good.Finally,the similarities and differences of compressive properties,splitting tensile properties and bending toughness between non oriented steel fiber test block and oriented steel fiber test block under different fiber content are compared by experimental method.The failure mode of steel fiber reinforced concrete test block is very different from that of ordinary concrete test block.Due to the joining effect of steel fiber,the further development of cracks will be hindered after the concrete is stressed and cracked.After orientation,the number of steel fibers connecting cracks will be greatly increased,which will be further improved.Moreover,due to the two-dimensional distribution form of steel fiber after orientation,It will make the bearing capacity of its components anisotropic.According to the experimental analysis,it can be seen that the mechanical properties of directional steel fiber specimens are much better than ordinary concrete and non directional specimens.