| With the continuous advancement of urban development process,the demand of concrete materials is increasing,and the durability of concrete structure has become a hot spot for scholars at native and foreignThis paper briefly introduces the classical theory of concrete freeze-thaw cycles,and summarizes the influence of freeze-thaw action on the mechanical properties of concrete and the sensitivity of concrete parameters.On the basis of concrete freeze-thaw test,through the study of the dynamic load test of structure,stress-strain curves of the structure under different freeze-thaw cycles,different strength grade of concrete,different loading rates are calculated.Using large-scale finite element software ABAQUS numerical simulation on heat transfer process of concrete freezing and thawing cycles,the thermal stress file is imported after the static analysis by different loading rates of concrete structure model,the corresponding stress-strain curves are obtained,through the comparison of the curve peak stress analysis the law of structure damage degradation.The numerical simulation results are compared with the experimental results,and the feasibility of the dynamic loading analysis of concrete under freeze-thaw cycles is verified.The results show that:(1)Based on the analysis of the heat conduction can effectively restore the temperature change of concrete in the freeze-thaw test,the node temperature and the temperature setting of fast freeze-thaw machine curve is consistent;(2)With the same strength grade and the same loading rate of concrete structure,the greater the number of freeze-thaw cycles,the more obvious decrease trend of stress,the steeper the decrease in the stress-strain curve;(3)With the same loading rate,the same concrete structure under freeze-thaw cycles,the higher level of intensity,the greater the peak stress,the stronger the frost resistance,with the increase of freeze-thaw cycles,the faster the stress drop,the more brittle characteristics significantly;(4)With the same strength grade,the same concrete structure of freeze-thaw cycles,the smaller the dynamic loading rate,the smaller the corresponding peak stress,and the slope of stress-strain curve rises gradually,the descending part finally stabilizes. |
