| Under the national policy vigorously support,at present,the construction of prefabricated construction in our country is in a stage of vigorous development,the construction process effectively reduces the architectural sewage,harmful gas,dust and noise emissions,reduced the construction of various effects in the surrounding environment,to improve the construction labor productivity,promote the design and construction of refinement,improve the overall quality of construction,save energy and decrease the rate of drainage,promote construction industry sustainable development in our country,to adapt to the needs of the development of national economy,will gradually become the mainstream of the building construction.In the construction process of prefabricated building,the connection between components is the top priority of construction,the quality of component connection is directly related to the structural safety of the building,currently the main way of component connection is reinforced sleeve grouting connection.If steel sleeve hole grouting material to appear,the casting defects such as imperfect,cause reinforced with grip of grouting material shortage,air in the cavity with water vapour can cause the sleeve inside the steel bar corrosion,impact contact intended use of the function,such as wind or earthquake under the action of horizontal loading,easily to connect the nodes to bear the load and damaged,which will cause the building shear wall,column,beam,loosening,and even collapsed structures,such as production.At present,this acceptance is mostly based on the site construction data,and there is no reliable qualitative or quantitative detection method for the defect of the compactness of the grouting material in the grouting sleeve.This test mainly uses the impact echo method to judge the compactness of the grouting material of the sleeve joint at the grouting sleeve joint and verify the mechanical properties of the sleeve joint under different compactness.The main contents and results of this study are as follows:1.The corresponding relationship between the waveform image and the grouting plumpness of the sleeve joint was established.Based on the principle of impact echo method,the defect of grouting material in reinforced grouting sleeve joint was detected and verified by impact echo instrument.By using the waveform image generated by impact echo instrument,the grouting compactness of the sleeve joint placed in the center of steel bar is judged by the method of auxiliary line length proportion,and the corresponding relationship between the impact echo image and the grouting plumpness of the sleeve joint is established.A large number of experiments have proved that it is feasible and accurate to detect the grouting compactness of sleeve joints by using the shock wave method.2.The corresponding relationship between sleeve grouting plumpness and joint strength was established.The in-center tensile test was carried out on the sample with the grouting plumpness of 30%-100% in the sleeve joint.The mechanical properties of the joints with different grouting plumpness were verified by high stress and large deformation tests of the samples with a plumpness of 70%-100%,and the corresponding relationship between the sleeve joints with different grouting density and their mechanical properties was proposed.3.The corresponding relationship between waveform image,grouting material plumpness and node strength was established.According to the research results obtained from the above tests,the corresponding relationship between waveform image,grouting material plumpness and joint strength was established for sleeve joints with different grouting plumpness.It is verified that the mechanical properties of the grouting sleeve joint with compactness less than 70% can not meet the design requirements.The mechanical properties of the tensile strength were inferred to determine the mechanical properties that the joint could achieve,so as to provide data support for the reinforcement and processing in the later stage.For the grouting sleeve joint with compactness ≥70%,its mechanical properties can meet the design requirements,and it can be judged that it meets the standard of qualified joints.In terms of design,it can be considered that its joint parts are equivalent to in-situ casting.In this paper,by making sleeve joints with different grouting compactness and testing them by impact echo method,it is proved that the impact echo method has high accuracy and application in the detection of sleeve grouting compactness.Based on different single tensile test of the compactness of joint,high stress and pressure,large deformation and compressive test repeatedly,verify the shock wave of different grouting compactness joint images and the corresponding relation of mechanical performance,and then puts forward the waveform images corresponding relation,grouting material plumpness,node strength,for the safety of the prefabricated building node location performance appraisal,defect detection testing provides a reference method. |
