Damage evolution model of early disturbed concrete under sulfate attack and its experimental verification

Abstract

The disturbance during the early age of the setting and hardening stage of concrete usually creates microcracks in the concrete
matrix and thus decreases its strength and durability. Among the
factors that affect the durability of concrete, sulfate attack is one
of the important factors that cause damage. To analyze the damage development of early disturbed concrete under sulfate attack
environment, the residual coefficient of flexural strength of concrete was tested by the perturbation of horizontal vibrating table.
Using erosion damage factor to characterize the degree of erosion
deterioration of concrete, the sulfate attack tests were carried out
on the disturbed concrete. Starting from the crack initiation condition of sulfate attack, and based on the theory of microcrack
nucleation and growth in the process of erosion, the statistical
evolution equation of sulfate corrosion damage of concrete was
obtained by using micro crack propagation to characterize the
mechanical behavior of concrete after corrosion damage. Considering the influence of early disturbance on the critical stress of
concrete microcrack nucleation, the damage evolution model of
concrete with different disturbed conditions under sulfate attack
was established, and the corrosion degree of disturbed concrete at
different erosion ages was predicted. Based on the experimental
data of damage factors, the damage evolution equation was fitted
and the model was validated. Results demonstrate that the damage model curve fits well with the test curve of damage factor,
and the correlation coefficients are above 0.98, which can reflect
the damage evolution law of disturbed concrete sulfate attack.
This method provides a good reference for evaluating the effect of
early disturbance on the sulfate resistance of concrete.