Analysis of the Relationship between Mechanical Properties and Pore Structure of MSW Incineration Bottom Ash Fine Aggregate Concrete after Freeze-Thaw Cycles Based on the Gray Theory

Abstract

The destruction of concrete building materials in severely cold regions of the north is more severely affected by freeze-thaw cycles, and the relationship between the mechanical properties and pore structure of concrete with fine aggregate from municipal solid waste (MSW) incineration bottom ash after freeze-thaw cycles is analyzed under the degree of freeze-thaw hazard variation. In this paper, the gray correlation method is used to calculate the correlation between the relative dynamic elastic modulus, compressive strength, and microscopic porosity parameters to speculate on the most important factors affecting their changes. The GM (1,1) model was established based on the compressive strength of the waste incineration ash aggregate concrete, the relative error between the simulated and actual values in the model was less than 5%, and the accuracy of the model was level 1, indicating that the GM (1,1) model can well reflect the change in the compressive strength of the MSW incineration bottom ash aggregate concrete during freeze-thaw cycles. Using the gray correlation method, the correlation between the relative dynamic elastic modulus, compressive strength, air content, specific surface area, pore spacing coefficient, and pore average chord length was calculated, and the pore spacing coefficient and pore average chord length were determined to be highly correlated with each other. This determination can help analyze and infer the deterioration mechanism of concrete subject to freeze-thaw cycles. These results can provide a theoretical basis for guiding the engineering practice of concrete with fine aggregates of household bottom ash in the northern cold region.