Research On Quality Detection Technology Of Monolithic Precast Concrete Shear Wall Structure Joints

Fabricated buildings can protect the environment,shorten the construction period and reduce energy consumption effectively,they Meet the needs of sustainable development and are supported and promoted strongly by the government.With the expansion of fabricated buildings industry scale,the quality and safety of fabricated buildings have been widely concerned by the public,they have also become the focus of management at all levels of government construction.There are essential joints and joints in fabricated concrete structures,The reliable connection between joints and joints is the key link of prefabricated concrete structure,it directly affects the quality and safety of fabricated concrete structures.It is precisely because of the construction quality control lax that hindered the development and promotion of prefabricated buildings in China to some extent.it is urgent to develop an effective method to detect joint and joint quality.At present,the joints of prefabricated concrete structures in China are mainly rebar splicing by grouting sleeve and rebar lapping in prout-filled hole,the seams are divided into horizontal seams and vertical seams.There are two construction techniques for horizontal seams,namely horizontal joints for seaming construction and horizontal joints for joint cavities.Due to the relatively simple medium environment,the quality testing of horizontal slurry joints and vertical joints can refer to the nondestructive testing method of concrete defects.However,the grouting construction of reinforced rebar splicing by grouting sleeve,rebar lapping in prout-filled hole and horizontal joint connecting cavity is a concealed project,and its quality inspection is a difficult problem at home and abroad.This paper first introduces the basic principle of ultrasonic detection of defects,and then around the horizontal joint grouting quality,sleeve,slurry grouting anchor fittings quality of grouting quality of ultrasonic testing technology research,finally analyzes the different grouting plumpness half-and-half socket connector mechanical properties and the effect of grouting formed a set of testing principle,testing instruments,test method,test results rating of complete sets of testing technology.The main research results and corresponding research results are as follows:(1)inspection of grouting quality of horizontal jointsAccording to the characteristics of horizontal joints in geometry space and material composition,a high-frequency small diameter ultrasonic transducer was developed.Considering the types of grouting defects that may occur in the construction site,the test components were designed and tested by the improved ultrasonic method.The results show that the improved ultrasonic method can effectively identify the hole defect,porous foam,plastic pad,and PVC wire pipe,which is not affected by the connecting steel bar.(2)inspection of grouting quality of joint connectionAccording to the actual design of the project,the grouting anchor lapped connection shear wall components and sleeve grouting connection shear wall components were designed and manufactured.Different grouting defects were set.Ultrasonic cross section imaging method was used for detection.The results show that the ultrasonic cross section imaging method can only qualitatively determine the defect and fullness of the shear wall members connected by the slurry anchor lap joint,and misjudgment may occur;The ultrasonic section imaging method should be used to detect the filling degree of the sleeve at the detection surface far away from the sleeve.The overall scanning imaging detection has a high accuracy,but there will still be misjudgment.The single imaging across the sleeve can improve the accuracy of the detection results.In view of the fact that ultrasonic cross-section imaging method can only qualitatively detect grouting fullness and there is a miscalculation,the research team developed the pre-perforated endoscopy method,which has been verified by laboratory research and engineering examples to be able to quantitatively detect grouting fullness with high detection accuracy and intuitive results.(3)Study on the effect of plumpness of grouting material on the performance of rebar splicing by semi-grouting sleevesFor GT14 and GT25 semi-grout sleeves,the mechanical properties of rebar splicing by semi-grouting sleeves with different plumpness of grouting material were tested.The test results show that when the plumpness of grouting material reaches 70%,the medium uniaxial tensile strength,deformation performance and ultimate tensile strength of the rebar splicing by semi-grouting sleeves can meet the requirements of the specification.The mechanical properties of the rebar splicing by semi-grouting sleeves will be slightly reduced due to the deflection of the steel bar in the sleeve.