Study On The Mechanical Property And Bond Anchorage Property Of Self-compacting Lightweight Concrete

Lightweight aggregate concrete(LWC)has the characteristics of light weight,high strength,thermal insulation,refractory antifreeze,etc it Can significantly improve seismic performance and durability of the structure.But SCLC has the problem of Low modulus of elasticity,poor ductility with damage occurred in the aggregate and the thickness of aggregate stratified phenomenon is serious because of increase of the aggregate in the concrete construction process.Self-compacting fiber lightweight aggregate concrete(SCLC)with the advantage of lightweight aggregate concrete and self-compacting concrete which can significantly improve the ductility and improve the construction technology of lightweight aggregate concrete,but less in terms of the research at home and abroad.Therefore,this paper has made a systemic study on mixture ratio design,performance,failure mechanism,microstructure characteristics,slippage of SCLC on the previous investigations by other scholars as follows:(1)Mixture ratio design and performance.By considering the raw materials and by adjusting the water-binder ratio,content of admixture,six mix proportions for SCLC are designed by the overall calculation method with fixed fine and fixed fine and coarse aggregate contents after many times revised tests.The workability of the six types of fresh SCLCs is quantitatively evaluated by the slump flow,V-funnel,L-box,U-box.The uniformity of distribution of LWAs along the specimen is also evaluated by profile.It can be concluded that the workability of six mix proportions SCLCs is good and can meet the requirements of actual work.(2)Basic mechanical.The cube compressive strength,splitting tensile strength,bending strength of the six mix proportion SCLCs were study by system and have a in-depth analysis of the influence of fiber on the mechanical properties.It can be concluded that coarse aggregate of shear failure is the important reason for leading to SCLC presents obvious brittle failure and the splitting tensile strength,the bending strength,the toughness,the characteristics of brittle failure of SCLC can be improved by adding fiber.(3)Microstructure.The Coarse aggregate-slurry interface,fiber-slurry interface of SCLC with different age and different mineral were test by using electron microscope scanning(SEM)technology.It can be concluded that SCLC interface transition zone is very dense,bonding performance is better than that of ordinary concrete,the interface connection with aggregate were enhanced and the ductility were improved.(4)The bond anchorage behavior.Strength grade of concrete,steel bar diameter,bar anchorage length,different fiber content were analysis to find out the effect and the reason on the bond-slip of Self-compacting lightweight aggregate concrete by designing 10 center drawing test specimen.SCLC bond strength calculation model was put forward through the theoretical analysis and the stress-slippage of the constitutive relation model between SCLC and steel bars was established.It can be concluded that the cement paste and aggregate strength together decided the bond strength,paste intensity of influence is greater than the coarse aggregate.The stress-slip constitutive relation model results agree well with the test results.Thesis research results can provide theoretical basis for the engineering application of lightweight aggregate concrete and provide ideas to improve ductility of lightweight aggregate concrete which has important theoretical significance and practical value.