Experimental Study On The Influence Of Quality Factors Of Prefabricated Concrete Slurry Anchor Connection

With the improvement of our country building industrialization level,prefabricated concrete structure began to rapidly developed,and the key to structure node connection of safe and reliable is to ensure that the key of the fabricated structure have been developing steadily.The slurry anchor connection is one of the main ways for vertical rebar connection of prefabricated concrete structure.In this paper,the influence of various quality factors on the properties of slurry anchor joints and the impact of grouting defects on the aseismic performance of grouted concrete columns are studied.At the same time,the detection method of grouting defect is explored and the corresponding indexes are put forward.The content of this paper is part of the "construction quality acceptance method and standard system of industrialized construction"(2016YFC0701805)of the national science and technology support plan of the 13 th five-year plan.Main research contents and work include:1.According to the actual engineering investigation and simulation test analysis,summarize the common quality problems and classify them and analyze their formation mechanism.2.The design and production of the various quality factors(grouting end,middle and discrete defects,inferior grouting materials,eccentricity,etc.)of 80 slurry anchor joints were designed and produced.3.The design and production of four slurry anchor joints connecting the assembled concrete columns,one without defect,and the remaining three with varying degrees of defects,carried out low-cycle repeated load test.4.The detection effect of impact echo method and concrete ultrasonic imager on the defect of grouting grouting was studied.5.Summarize all kinds of test data and preliminarily establish the basic indicators for acceptance of pulp anchor nodes.The experimental results show that: 1.The main quality problems of slurry anchor connection include end defects,middle defects,discrete defects,secondary water blending or sand grouting,and eccentricity of reinforcement,etc.Mainly because the grouting construction operation is not standard and so on.2.Considering the actual construction situation,it is considered that the influence of the connection of the slurry anchor is negligible,which is the quality problem within the acceptable range,considering that the defect of the end part is less than 40% and the middle defect is less than or equal to 30%.3.Due to the great influence of discrete defects on the performance of slurry anchor connection,such defects are not acceptable.4.Under the same defect condition,the end defect has the least influence on the slurry anchor connection,the central defect has a larger influence,and the discrete defect has the greatest influence.5.The metal bellows can provide a certain lateral restraint,and the helical stirrup is basically unstressed,and can be removed with spiral stirrup.6.The quality of the slurry anchor connection is greatly affected by the bad grouting materials such as sand mixing and water mixing,which should be strictly prohibited,and the quality of the slurry should be strictly controlled.7.The larger the load,the greater the impact of the defect on the connection performance of the slurry anchor.In the actual project,the diameter of the longitudinal bar with the slurry anchor connection should not exceed 20 mm.8.The effect of steel bar slanting or offset on the performance of the slurry anchor connection is very small,which is the quality problem within the acceptable range.9.Under cyclic loading,the influence of defects on bearing capacity is basically the same as that of monotone load,and has a great influence on deformation performance.10.The construction disturbance in a small scope has limited impact on the grouting anchor connection,but considering the actual construction situation,the disturbance range of the component is often large,and the next step should be carried out after the grouting is completed in 3d.11.When the strength of the slurry is greater than 60 MPa,it can meet the requirements of the grouting anchor connection,and the qualified pulp anchor material produced by the manufacturer with relevant qualification shall be adopted.12,defect of grouting anchor lap connection concrete column’s bearing capacity,ductility,stiffness and energy dissipation are larger,the influence of the bearing capacity,ductility,stiffness,and the least energy consumption dropped by 20%,16%,36% and 16%;13.Grouting full slurry anchor connection column has good seismic performance.The detection results show that the impact echo method and the concrete ultrasonic imager have limited recognition of the grouting defect,the result is not satisfactory.At present,there is still no suitable method for direct detection of grouting defects,and it is suggested to conduct the inspection and acceptance in an indirect manner.In this paper,a series of research is made on the connection of slurry anchor.This paper mainly demonstrates the influence of quality problem on the performance of the pulp anchor connection,summarizes the relevant data and results,and preliminarily establishes some acceptance indexes.It can provide some reference for the establishment of the acceptance specification for the late slurry anchor.