Research On Size Effect Of Uniaxial Compressive Mechanical Properties Of Sulphate Attacked Concrete

Damage and accumulat ion of c oncrete structures will inevitably occur under the action of environmenta l erosion.Long-term damage accumulation can lead to deterioration of mechanical properties of materials,thereby reducing the safety and applicability of structures,and even causing early failure of structures.The durabilit y of the concrete structure design can effective ly improve the sulfate corrosion environment serving the safety of the structure,but the deterioration of concrete under sulfate corrosion model has not been clear,with the assumption of isotropy based concrete constit utive relations hip method is not applicable to environmental erosion concrete,the constit utive relation of concrete deterioration area did not get real.In view of the above proble ms,this topic w ill be systematically studied in the following aspects:The experimental study on the uniaxial compression performance of sodium sulfate corrosion concrete is carried out.A single axia l compression test was carried out on the specime ns with different erosion cycles,different sizes and different working condit ions,and the test results were analyzed.C onsidering t he inhomogene ity of erosion degree,the time-dependent damage constitut ive relation of concrete in sodium sulfate eroded area is established,and ver ified by different size concrete test data.The test results show that sodium sulfate has influence on the size effect of concrete strength,the phenomenon of size effect on the strength of concrete after erosion than the erosion of concrete is more signif icant;size effect has a significant impact on the peak stress,with the increase of specimen size,the peak stress was gradually decreased;the size effect has a certain influence on the peak strain over time,the size increases,the peak strain generally decreased;the size effect has little effect on the elastic modulus.The research of piezoelectric intelligent monitoring for the evolut ion process of regional damage caused by sodium sulfate erosion is carried out.Build a piezoelectric intelligent monitoring system of concrete structure,monitoring ind icators specifically applicable to the damage detection of concrete;the concrete specimens of different depth and location of embedded piezoelectric smart sensors for different degrees of accelerated erosion of sodium sulfate,and sodium sulfate erosion monitor ing platfor m operation monitoring damage change monitoring index in the process of development,given the damage at different depth of sodium sulfate erosion evolution equation.Based on the abaqus finite element platform,a mult i dimensiona l polygon random aggregate model is established.Based on the mechanical characterist ic value for mula of concrete obtained by compression test,the mechanical properties of concrete materia ls with different size and different erosion time are calculated,and different calculat ion results are given to units in different regions of the model.The simulation results are compared with the test results,and the rationa lit y of the simulation method is proved,and the proce ss of the compression test is reproduced by the numerical simulation method.