Study On Mechanical Properties Of Ferrous Mill Tailings Concrete Columns After Fire Under Axial Compression

Large-scale mining of fine aggregate in concrete will damage the environment.Using Ferrous mill tailings to replace natural sand can solve the problem of shortage of natural sand and reduce environmental pollution caused by iron tailings.Due to the instability of Ferrous mill tailings under high temperature,the study of mechanical properties after high temperature is conducive to damage assessment and repair and reinforcement of damaged parts.This paper analyzes the residual capacity of Ferrous mill tailings columns with different parameters under different fire times and compares them with ordinary columns under axial compression.Research contents are as follows:1)Determine the highest temperature experienced by the column through finite element numerical analysis combined with the subroutine UEXPAN and USDFLD,and determine the corresponding constitutive properties of the material.2)The numerical model of temperature field and force field was established,and its validity was proved by comparing with the experimental results.Through the calculation results of temperature field,it is found that the variation rule of temperature field of Ferrous Mill Tailings concrete is roughly the same as that of ordinary concrete.3)The influence of the five parameters on the residual bearing capacity of the column can be concluded as follows: the fire condition and section size significantly affect the residual bearing capacity;The influence of slenderness ratio and protective layer is small and decreases with the increase of fire exposure time.With the increase of concrete strength,the damage degree increases gradually.Compared with ordinary concrete columns,the residual bearing capacity of Ferrous mill tailings columns under axial compression is lower after high temperature,but the reduction law of them after fire is similar to some extent.In practical engineering application,parameters such as slender-to-slender-to-concrete strength should be reasonably designed to ensure the fire safety of the columns.Figure 29;Table 8;Reference 78...