Research On Restoration Of Defective Concrete Eccentric Compression Column Based On Different Methods Of Hole Drilling

Since the 1980 s,the method of sampling the actual strength of drill cores has been applied to the detection of concrete structures.The core drilling method has the advantages of simple operation,low cost,and strong reference for reference,so it is used in a large number of engineering inspections.However,the core drilling method is a semi-destructive testing method for drilling a core sample from the inside of a concrete core.After core drilling,the hole left behind tends to reduce the bearing capacity of the component,resulting in a structural defect of the concrete core section.For the filling of the remaining holes,people often do not pay enough attention to the damage caused by structural section defects.There is no scientific understanding.Today,the safety of building construction is increasingly valued.The discussion of the repair method of holes has very important significance.In order to make academic research not only at the door of the practice,the experimental conclusion can be applied to the actual project.This experiment studied the impact of the eccentric core and the different ways of hole filling on the performance of the test piece,which is fully compatible with the current detection industry.Combining the pressure column with drill hole filling method has academic innovation and engineering reference value.In the experiment described in this paper,a group of eight short columns with the same structure were designed and manufactured using a controlled test.The designed eccentricity was 50 mm.Each set of test pieces used an independent test procedure,and repaired the damaged parts of the test pieces by using two kinds of repair methods: micro-expanded concrete and pre-formed cores with epoxy adhesives.The test pieces were under stress in the corresponding state.Mechanical properties and displacement deformation.1.Eight concrete columns of the same size are poured,HRB400 steel reinforcement is used for longitudinal reinforcement,HPB300 steel reinforcement is used for stirrups,and C25 is designed for concrete strength.The test specimens are cured for 28 days under standard conditions.Surface treatment is performed after the test pieces are removed from the mold.Set the measuring point.2.The test pieces are divided into two groups and divided into four groups.Four load test methods are performed respectively: the intact test pieces are directly loaded to the damage,the damaged parts of the core are not filled and loaded into the damage,and the cores are used after the prefabrication of the core columns.After the adhesive steel is filled in the broken part,it is loaded until it is damaged,cores are drilled,and fine-scale micro-expanded concrete is used to fill in the damaged part and then loaded into the damage.In the test,for a test piece requiring a core drilling,a stable load state of 900 kN is maintained,and for a test piece to be filled with a hole,the load is maintained in a constant state for 72 hours.The test designs a method for maintaining the load for a long time under a power failure state of the hydraulic test machine to ensure the safety of the test machine and the stability of the load.3.The test carried out a vertical static load carrying capacity static load test on eight test specimens prepared.The VP-CSS40 data acquisition instrument was used to collect various data.The load capacity and strain indicators of the test specimens were recorded during the test,and the development of cracks was studied.In the case,the corresponding data curve is depicted,the test phenomenon is described and the test conclusion is drawn.The test results reflect the degree of repair of damaged specimens by different filling methods.Combined with the actual testing procedures in the project,the convenience,remediation and construction maintenance of the two types of repair methods were discussed,and the micro-expanded concrete backfill was obtained.The holes can be well matched with the concrete of the original specimen,and the performance recoverability is obvious.The prefabricated core pillar has obvious strengthening and restoring effects on the bearing capacity and lateral displacement,and both have their own advantages.