The Shrinkage Of Core Concrete And It's Influence To The Mechanical Performance Of The High Strength Concrete Filled Steel Tube

AbstractHigh strength concrete filled steel tube(CFST) is a kind of perfect composite material and its application is getting more and more widely. But the autogenous shrinkage of core concrete will be increase with the increase of core concrete strength. The influence of autogenous shrinkage to high strength CFST should be investigated. In this paper we made finite element analysis on the shrinkage influence of the CEFT and did a series of shrinkage and mechanical tests.1.To analyse the strength increase mechanism of CFST. To modify the finite element procedure considering the influence of shrinkage and create a series of compression-strain curves of CFST under axial compression depending the calculating results to analyse the influence of shrinkage on the mechanical performance of CFST under axial compression.2.To summarize the shrinkage and expansion mechanism of core concrete.3.To research the mixing methods of high strength concrete and decide the mix ratio of core concrete of the specimens.4.A set of equipment was designed for the shrinkage determination. Eight groups of test specimens was made to investigate the influence of different water binder ratio, mineral admixtures and size of the specimens. Theoretical analysis was made on the test results.5.Mechanical tests were made on 4 groups of the specimens and the compression-stain curves were drawed and compared with the curves produced by calculate to validate the calculation procedure.