Using micro-CT to Examine Material Structural Properties

Through the assessment and modeling of construction materials, researchers can derive detailed structural predictions of material performance over time1. Micro-CT provides a tool for civil engineers to non-destructively examine structure and generate a detailed map of the internal features suitable for use in finite element analysis. These powerful computations can be coupled to physical testing of samples to calibrate predictive models of material performance in real-world scenarios.

For our demonstration in examining both asphalt and concrete this month, we chose to utilize our SkyScan 1173 system because of  its large sample capacity, high power, and fine spatial resolution.

Micro-CT Scans of Paving Samples

After reconstructing the x-ray attenuation data for both materials, we are able to examine both samples in two-dimensional views from each of the coordinate axis directions (Figure 1). This allows us to pinpoint interesting features within the samples while also observing the overall structures that are present in each sample.

In both samples we observe large aggregate particles present (bright large shapes), with the aggregates present generally appearing larger in the concrete than in the asphalt sample examined (Figure 2). In these images, higher density areas scale towards green while lower density areas scale towards black. We observe the large aggregate particles clearly highlighted in green for both samples.

In addition to reviewing the samples in two-dimensional views, we also can create realistic 3-dimensional renderings for still images and video files suitable for presentation or publication (Figure 3).

Conclusion

Micro-CT can be used to assess the internal features of paving materials, such as porosity, aggregate sizing, and particle distribution, while also generating detailed structural information suitable for further computer modeling and simulation. We hope you found this image of the month illustrative. If you have an image of the month sample that you would like us to scan, please contact us by calling Seth Hogg at 610-366-7103 or e-mailing seth.hogg@microphotonics.com

Scan Specifications

All scans completed on our large capacity SkyScan 1173 micro-CT system at the Micro Photonics Imaging Laboratory in Allentown, PA. Reconstructions were completed using NRecon and visualization of 2D and 3D results were completed using DataViewer and CTVox.

Works Cited

1. https://www.intechopen.com/books/computed-tomography-advanced-applications/the-use-of-computed-tomography-to-explore-the-microstructure-of-materials-in-civil-engineering-from-