Study on the Performance Degradation of Concrete Under Freeze-thaw Cycles Based on Mesoscopic Mechanical Models
To clarify the influence of mesoscopic characteristics on the structural performance degradation of con-crete under freeze-thaw conditions,a three-dimensional mesoscopic mechanical model of concrete under different freeze-thaw levels was developed using ABAQUS secondary development,combined with freeze-thaw cycles and uniaxial compression test results.The mechanical performance of concrete with varying aggregate characteristics was analyzed using peak stress and peak strain as evaluation metrics.The findings are as follows:(1)During com-pression,cracks in the concrete initiate around the aggregates,primarily appearing in the mortar and interfacial layers.Diagonal surface cracks form in the early stages of loading,while microcracks appear in the central internal region.As compression displacement increases,the length and width of cracks grow,and diagonal cracks rapidly extend in-to through-cracks,causing structural failure;(2)As freeze-thaw damage intensifies,the damage distribution in con-crete becomes more extensive,and crack width and length increase;(3)With increasing freeze-thaw cycles,larger aggregate gradation and particle size result in a greater rate of change in peak stress and a smaller rate of change in peak strain.Conversely,higher aggregate content leads to smaller rates of change in both peak stress and peak strain;(4)Optimizing aggregate gradation,increasing aggregate content,and reducing aggregate particle size im-prove freeze-thaw resistance and compressive strength of concrete,while aggregate shape has no significant impact.
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维普
