| In recent years,the fabricated structure has been deeply valued and widely used,and its overall working performance has attracted much attention.The connection between components is critical,and the sleeve grouting connection is one of the commonly used important connection methods.The overall quality of the structure will be directly affected by the quality of the sleeve grouting connection,and it is critical to the safety of the structure to ensure the fabricated shear wall structure sleeve grouting compactness.Therefore,a correct and reasonable non-destructive testing method is adopted to detect the compactness of the sleeve grouting connection,which is of great significance to the safety and durability of the fabricated structure.First of all,in this thesis,through the acoustic emission(AE)system composed of an AE instrument and a signal generator,the compactness of the grouting connection of the fabricated shear wall sleeve was initially tested,and the AE signals of different working conditions were analyzed.The results show that: In the C40 specimen with the sleeve centered,the AE signal amplitude,energy,RMS,ASL,rise time and frequency can be used as the parameters for evaluating concrete specimens such as compact sleeve,hollow sleeve,no sleeve,and spliced rebar compact sleeve.However,the AE signal duration and ring count cannot evaluate the above working conditions;the amplitude,energy,RMS and ASL of AE signal of concrete specimens such as hollow sleeve,no sleeve,spliced rebar compact sleeve and compact sleeve increase in turn,and the rise time of AE signal of concrete specimens such as hollow sleeve,compact sleeve,spliced rebar compact sleeve and no sleeve decreases in turn.Secondly,the influence of the material characteristics of the fabricated structural shear wall on the testing results of the sleeve grouting compactness was explored.The material characteristics of the fabricated structural shear wall include concrete strength,sleeve material and the type of grouting material in the sleeve.The received AE signals were analyzed by the AE system combined with the signal generator and AE technology.The results show that: AE signals RMS,ASL,rise time and frequency are less sensitive to concrete strength evaluation,so it is not suitable for the compactness detection of fabricated structural sleeve grouting affected by many factors.The AE signal amplitude and energy are more sensitive to concrete with a small difference in compactness,and can be used to analyze the influence of material characteristics;the concrete strength of the fabricated shear wall specimen increased from C30 to C40,and the amplitude and energy of the AE signals increased accordingly;the amplitude and energy of the bellows sleeve are both less than that of nodular cast iron and carbon steel sleeve,and the amplitude energy of the latter two is not much different.Compared with the sleeve materials,the volume and shape of the sleeve has a greater impact on the AE signals;AE signals will be affected by the types of grout,the more compact UJOIN-108 type grout amplitude and energy are 68.4 d B and 29.5 m V*m S,BY(S)-YJ85 type grout amplitude and energy are 67.4 d B and 19.5 m V*m S,the amplitude and energy of UJOIN-108 type grout is greater than BY(S)-YJ85 type grout.Finally,the AE system composed of an AE instrument and a signal generator was to study the grouting problems such as no grouting,grouting emptying,and grouting compaction in the concrete sleeve grouting connection of the fabricated shear wall.it is divided into four types of common grouting problems: no grouting,slurry backflow in the sleeve outlet,no slurry in the sleeve outlet and slurry in the sleeve outlet.The results show that: in the C30 specimen with the plum blossom arrangement of the sleeve,the AE signals such as amplitude,energy,RMS,ASL,rise time and frequency were analyzed,and the amplitude,energy and frequency can be used as the parameter basis for evaluating four common types of grouting problems,such as no grouting,slurry backflow in the sleeve outlet,no slurry in the sleeve outlet and slurry in the sleeve outlet;the difference between the energy of the AE signals of the slurry backflow in the sleeve outlet and no slurry in the sleeve outlet is small,and the amplitude difference is large.The amplitude of the AE signals is more sensitive than the energy to the compactness of the sleeve grouting.The amplitude in each working condition is more distinguishable.The amplitudes of no grouting,slurry backflow in the sleeve outlet,no slurry in the sleeve outlet and slurry in the sleeve outlet are increased sequentially,which are 62.6 d B,64.6 d B,65.5 d B and 68.1 d B respectively. |
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