Experimental Study On Vibration Characteristics Of Fiber Reinforced Concrete Based On DIC

Concrete has become an indispensable building material in today’s human society,because of its extensive material sources,high strength advantages,it is widely used in various construction projects.But in the actual use of the process,its toughness is relatively poor,but also relatively easy to produce cracks,doped fiber materials in concrete can effectively improve these problems.At present,in construction engineering,in order to improve the strength of concrete,the use of more means is to mix a variety of fibers in concrete.In order to study the vibration characteristics of fiber reinforced concrete under earthquake,the polyvinyl alcohol(PVA)fiber and steel fiber were used as the additive fiber,shaking table is used to simulate earthquake action,digital image correlation method was used to record and analyze the transverse principal strain,load cycle time and crack propagation law at the initial crack of fiber reinforced concrete column joints,the simulation results are compared with the experimental results.The main research contents are as follows:1、Standard cube blocks were made during the pouring of fibrous concrete square columns,with 3 cubes for each square column,it was divided into two groups.The first group: the PVA fiber was mixed into the concrete with the dosage of 00.05% 0.1% 0.15% 0.2%;the second group: keep the total amount of the two kinds of fibers unchanged at 0.2%,increase the content of the copper-plated microfilament steel fiber from 0.05% to 0.1%,0.15%,0.2%,with a total of 27 test blocks.The cube compressive strength test was conducted.The results show that the strength of concrete without fiber is increased by 10.26%,12.58%,18.21% and 19.54%,respectively,with the increase of PVA fiber content.Compared with the concrete mixed with 0.2% PVA fiber,the compressive strength of the hybrid fiber concrete increased by 3.9%,6.4%,7.8%,8.9%,respectively.The increase range was small,but the crack resistance effect was significant.2、The vibration characteristic test of PVA fiber reinforced concrete was carried out:Five dumbbell shaped concrete square columns were designed,and the fiber was mixed with the doping ratio of 0,0.05%,0.1%,0.15% and 0.2%.Spray speckle on the surface of the square column.Digital image correlation method was used to measure the transverse strain,crack propagation and load action time at the initial crack of column joints in vibration experiments.The results show that,compared with ordinary concrete,the transverse strain decreases by 22.62%,36.77%,45.8% and 57.23% with the increase of mixing content.,the crack control effect is obvious,and the load cycle time increases by 25.3%,29.4%,40.2%,53.8%.3、Test of vibration characteristics of hybrid fiber reinforced concrete: the total amount of fiber incorporation was kept unchanged at 0.2%,The fiber mixed with concrete was kept at 0.2%,and the content of copper-plated microfilament steel fiber in the hybrid fiber was increased from 0.05% to 0.1%,0.15% and 0.2%.The results show that the transverse strain at the initial crack of the column joint decreases by18.03%,47.05% and 81.66%,and the load cycle time increases by 7.9%,15.8% and20.4% with the increase of the steel fiber mixing proportion.4、According to the test in Chapter 3,ABAQUS analysis software is used for simulation,,and the results show that the failure rule of the fiber-reinforced concrete square columns in the simulation is basically consistent with the experimental results.