Evaluation air void content of drilled porous asphalt mixture cores using non-destructive X-ray computed tomography

• Tomography technology is not usual when investigating drilled asphalt cores properties. Currently, there is no internationally recognised standard tomography method for asphalt pavements. Tomography provides, however, a non-destructive alternative to traditional, usually destructive, testing of drilled cores. Furthermore, tomography offers possibilities, which traditional laboratory analyses do not. It is not straightforward to distinguish mastic and aggre- gates in tomography results while air void content is less difficult to assess. To have a more reliable assessment of drilled cores properties found by tomography, the method must be carefully planned, executed, and the results compared to those of traditional laboratory methods. In this work, analysis was carried out using six in-situ drilled cores from a double layered porous asphalt pavement. This allowed a comparison of tomography and a standardised conventional laboratory air void measurement on the exact same samples. Comparisons of the air voids found by tomography in all three directions were also carried out, estimating how anisotropic and heterogeneous the samples are, which is not possible using traditional laboratory tests. As few as four tomography slices can give enough precision in the determination of air void content for the porous layers. No more than eight slices per sample were needed in the suggested tomog- raphy method. The statistical results did not indicate that the air void content determined by tomography is different from the laboratory results.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

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