Preparation And Finite Element Analysis Of Sleeve Grout For Rebar Connection

With the advent of the era of building industrialization,the status of prefabricated assembly structure and assembly technology is becoming more and more important.Prefabricated structure requires the formation of reliable and effective connection between components.Early strength high-performance sleeve grout is suitable for rapid connection between prefabricated components,secondary grouting of structural reserved gaps,with a broad scope of application and application prospects.In this project,P·O52.5 ordinary Portland cement,silica ash and fly ash were selected as the three-phase cementitious system of sleeve grout,quartz sand was used as fine aggregate,polycarboxylic acid high-efficiency water reducing agent was used to reduce water consumption and optimize working performance,swelling agent was used to compensate for self-shrinkage,new modified silicone defoamer was used to reduce the bubbles generated during slurry stirring,and early strength agent was used to improve the early strength of grout.The test results show that the cement substitution rate of silica ash and fly ash is about 30%,the dosage of water reducing agent is 2%,the dosage of swelling agent is 0.3%,the early strength agent is 0.5%,and the defoaming efficiency is the highest when the amount of defoamer is 0.2%.By continuously adjusting the mixing ratio,an early strength sleeve grout with an initial flow degree greater than 340 mm and a 28 d compressive strength greater than 85 MPa was prepared.In this project,the following main work was carried out :(1)The compressive strength test is carried out on the basis of the preparation of high-strength grout,and the compressive constitutive model curve of the grout is obtained based on the test data.(2)Prepare multi-scale grouting sleeve for high-stress repeated tensile and compression test,and study the applicability and reliability of the sleeve grouting connection through the strain detection of the sleeve and the final failure mode is studied.(3)Based on the early strength formula,three groups of water-cement ratio error grout joints were prepared,and the single-tensile mechanical properties were tested at different ages,and the influence of water-cement ratio error on the performance of the grouting joint with age was studied.(4)Based on the secondary development technology of Abaqus with Python,using random theory,the grout is regarded as mortar,fine aggregate and interface transition zone for three-phase meso-modeling.The particle size effect and size effect of three-phase composite materials are analyzed at the same time.The load-deformation curves of different models are obtained by displacement loading.The conclusions are drawn by comparison with each other,which provides a prilimilary reference for the preparation of composite cement-based grout.