Reliability Analysis of Magnesium Cement Reinforced Recycled Fine Aggregate Concrete in Complex Environment

In order to study the service life of magnesium cement reinforced recycled fine aggregate concrete in saline soil environment,magnesium cement reinforced recycled fine aggregate concrete specimens were prepared by controlling the content of recycled fine aggregate and exposed to Xining saline soil area.Resistance nondestructive testing,combined with SEM microscopic testing methods to compare and analyze the damage degree of the internal structure of the specimen,and established a life model based on the Wiener random distribution function.The results show that under the influence of both harmful ions and harsh climate environment,the dynamic elastic modulus evaluation parameter λ₁ of the specimen increases first and then decreases,and the steel corrosion evaluation parameter λ₂ always shows a downward trend;When adding 15%,30% and 45% of fine aggregate,the erosive ions such as Cl^-,CO^2-₃ and SO^2-₄ have an increased probability of invading the interior of the specimen with the increase of the content of regenerated fine aggregate.react with magnesium cement hydration products to form expansive crystals.λ₁ and λ₂ can be used as the durability degradation parameters to accurately obtain the reliability function of the specimen.λ₁ is used as degradation parameter,the working lives of the specimens with different dosages are 22 000d,20 000d and 16 000d,respectively,the service life obtained by the steel resistance value is 16 000d,15 000d and 12 000d respectively.The steel resistance durability is more sensitive,which can be used for daily maintenance and detection of reinforced concrete members.