[This article belongs to Volume - 51, Issue - 05]
Gongcheng Kexue Yu Jishu/Advanced Engineering Science
Journal ID : AES-16-10-2021-30

Title : Analysis of Performance Deterioration of Concrete Material with Initial Freeze-thaw Damage Under Salt-freezing Condition
Xu C, Cheng Y, Wang R, Zhang H, Bai W, H. Lian,

Abstract :

In order to find out the damage evolution rule of the concrete with initial damage caused by early freezing under the coupling of freeze-thaw cycle and sulfate erosion, initial damage to concrete specimens by freezing and thawing them at the 7th and 14th day during the preparation of concrete specimens was carried. Based on this, different initial damage degree on macro performance and internal structure was researched. Then according to the principle of damage mechanics, the dynamic modulus of elasticity and compressive strength were defined as damage variables, by regression fitting analysis of damage process of variable, and the damage evolution equation of different initial damage specimen caused by early freeze-thaw was established in corrosion and freezing environment. The results indicated that two kinds of concrete specimens with different initial damage are affected by early freeze-thaw in the decay process of their mechanical properties and their form are " lead effect", which is closely related to the degree of initial damage. At the same time, the comparison and analysis of the change process of ultrasonic pulse propagation velocity and internal defect zone of concrete inferred that early freeze-thaw accelerates the propagation speed of cavity and crack, and the initial value of macroscopic mechanical properties of concrete and the ability of resisting salt and freezing in later stage are affected. The dynamic modulus of elasticity and the damage evolution equation of compressive strength can be used as a general formula for the attenuation of mechanical properties of concrete with similar damage degree, which can provide a theoretical basis for evaluating the service status and predicting the life of structures in similar environments. At the same time, the damage relationship between dynamic modulus of elasticity and compressive strength can be deduced from each other, which can reduce the limitation of data acquisition due to the shortage of instruments.