Research On Nondestructive Testing Of Assembly Structure Grouting Connection

With the continuous development of housing industrialization in recent years,the scale of fabricated buildings is expanding.It is more and more necessary to study the quality detection technology of assembly structure components.Because of the particularity and complexity of the connection condition,the existing detection means can not meet the actual needs of the project.At present,there is no perfect detection method and standard for the quality of the connection part of the assembled reinforced concrete structure in the relevant specifications.Therefore,the non-destructive testing technology of sleeve grouting and slurry anchor lap grouting is studied in this paper.In this paper,the principle of damping vibration and the equivalent wave velocity method of impact echo are used to study the nondestructive testing of sleeve grouting and anchorage joint link nodes.Using the principle of damping vibration,put the vibration sensor into the buried metal sleeve in the three groups of the same specifications in advance,received and analyzed before and after grouting sensor signal amplitude attenuation and energy amplitude to determine whether the sensor coated with grouting material,to determine the density of the sleeve grouting material of the situation.With using the impact echo equivalent wave velocity method,the upper part of the three groups of slurry anchorage channel that anchored steel bar but with different grouting conditions are excited,then,receive the reflected signal and analysis the contour map,obtain the location and length of the hole defect,compare with the actual situation,and determine the reliability of the method.In addition,a set of slurry anchorage channels without anchorage reinforcement and ungrouted reinforcement and a set of slurry anchorage channels without anchorage reinforcement and grouting dense slurry anchors are set up as control groups to determine whether the anchorage bars affect the inspection data.The quantitative calculation of the grouting density in the grouting tunnel is also carried out by the analysis of these equivalent wave velocity data.In this paper,two kinds of NDT technologies are measured and tested in different working conditions.According to the test results,the grouting quality of the project is determined.Research shows that,(1)With useing damping vibration method,the vibration waveform diagram before and after the Grouting grouting can directly reflect the internal state of grouting sleeve was: waveform display features before filling large amplitude andamplitude attenuation is slow,and the output value of energy;waves of solidification grouting material after the show features of small amplitude speed,amplitude attenuation,and the output value is very small.This method can be used as the basis for detecting the density of the grouting in the sleeve,and it has the advantages of intuitionistic,reliable and quick.In the construction site test,we found that during the grouting process,the amplitude and attenuation rate of the waveform waveform were moderate compared with the laboratory results,and the output energy value was moderate,so we can interpret the vibrator in the fluid grouting material.Therefore,this method can be used as a monitoring means in the process of sleeve filling,which can be used to find out whether the grouting material in the sleeve is full,and whether it needs to be filled with two times.The quality evaluation and acceptance of the grouting work can be provided by classifying the grouting situation of the test points.(2)With using the impact echo equivalent wave velocity method,through the analysis of laboratory and field testing of the stress wave contour map,contour map can reflect the defects of each point: when the contour map in color on the abscissa represents the thickness,shown here should be after the stress wave the distance is equal to the thickness,the stress wave diffraction that did not happen,this decision point filling isoline dense;when the color on the abscissa represents the thickness of the right side,said here should walk through the stress wave greater than the plate thickness,indicating the stress waves diffraction,determine the test point filling density.The grouting density index of the point can be calculated by the equivalent wave velocity of the stress wave of each test point,and then the grouting quality of the whole slurry anchor pass is evaluated.It is found that this method can be used as a basis for evaluating the grouting quality of slurry anchorage by comparing the grouting density index with the actual grouting condition of the specimen.The contour map in the left part of color distribution,the judge may be because the concrete distribution within the component aggregate test caused by uneven stress wave propagation velocity changes,by adjusting the mixing ratio,concrete aggregate to improve after the test.