Quantitative analysis of geometric characteristics of crushed-stone-reinforced polymer composite microstructures

The stiffness and structural costs of a polymer can be effectively improved and reduced, respectively, by adding crushed stone aggregates. Therefore, it is necessary to study the effect of crushed stones on polymer composites. Scanning electron microscopy (SEM) and digital image processing analysis (DIPA) technology were adopted to study the micromorphologies of polymers and crushed-stone-reinforced polymer (SRP) composites with medium and high densities. A method for defining and determining the interface transition zone (ITZ) between the polymer and crushed stone was proposed. The distribution characteristics of the cell structure and ITZ in the SRP were statistically analyzed, and the influence of the crushed stone particle spacing on the polymer microstructure was explored. The results show that two types of ITZs are present in the SRP: low density (i.e., an ITZ density lower than that of the matrix) and high density (i.e., an ITZ density higher than that of the matrix). Furthermore, the relative content of the low-density ITZ decreases under the increase in SRP polymer density. The ITZ thickness in the SRP is generally below 1500 mu m. Under an identical polymer density, the ITZ thickness increases under an increase in particle spacing; under an identical particle spacing, the ITZ thickness increases with an increase in polymer density. This provides a theoretical basis for exploring the strength meso-mechanisms of SRPs and establishing meso-level finite element models.

Automated summary

This study investigates the effect of crushed stone aggregates on polymer composites and proposes a method for determining the interface transition zone. The results show that two types of ITZs exist in the composites, with their relative content and thickness being influenced by polymer density and particle spacing.