Experimental Study On Bonding Performence Of All-light Shale Ceramsite Concrete And Steel Bar

All-light shale ceramsite concrete is a new type of lightweight aggregate concrete with shale ceramsite and shale ceramsite as aggregates.advantage.Under the background of my country’s "14th Five-Year Plan" that "accelerates the green transformation of development mode" and "deeply promotes the low-carbon transformation of industry,construction,transportation and other fields",all-light shale ceramsite concrete is a kind of impact on the construction industry.New building materials that are of great significance to achieve the goals of "carbon peaking" and "carbon neutrality" have good development and application prospects.At present,the research on lightweight aggregate concrete in China is mainly based on sand-light concrete,and research on all-light concrete is extremely rare.In order to promote the application of all-light shale ceramsite concrete,it is necessary to conduct basic mechanical properties,bonding and anchoring properties Numerous experimental studies.In view of this,this paper conducts experimental research on the bonding performance of all-light shale ceramsite concrete and steel bars.The main research contents are as follows:(1)Taking LC20,LC30,LC40,and LC45 as concrete strength indicators,three kinds of steel bars,HPB300,HRB400,and HRB500,were selected,and four kinds of steel bar diameters,Φ14,Φ16,Φ20,and Φ25 were considered,and 57 center pull-out specimens were made for research.Bonding properties of all-light shale ceramsite concrete and steel bars.The research results show that:when the anchoring length is 5d,the ultimate bond strength of HRB400 and HRB500 steel bars and all-light shale ceramsite concrete has no significant difference;the ultimate bond strength is approximately proportional to the tensile strength of concrete;the larger the diameter of the steel bar,the greater the,the lower the ultimate bond strength;the ultimate bond strength of the smooth round steel bar and the full light shale ceramsite concrete is lower,only 19.07%～46.33%of the ribbed steel bar.(2)The ultimate bond strength is one of the most important parameters in engineering design.The existing calculation methods of ultimate bond strength have large errors when applied to all-light shale ceramsite concrete.The theoretical value of the calculation formula for the ultimate bond strength of all-light shale ceramsite concrete and steel bars is in good agreement with the measured value,which can provide a reference for practical engineering applications.(3)Considering factors such as steel bar diameter,concrete strength,protective layer thickness,etc.,30 beam-type specimens were made by inserting strain gauges in steel bar grooves,and the ultimate adhesion between all-light shale ceramsite concrete and steel bars was studied.Joint strength and distribution of strain and bond stress in the anchorage section of steel bars under various loads.(4)Based on the finite element software Abaqus,the center pull-out specimen model was established,and the bond-slip constitutive relation proposed in this paper was used to define the slip properties of the contact surface between the steel bar and the concrete.The accuracy of the resulting constitutive relation.