In Innovative Ap Approach to o th the As Assessment of of Roa - - PowerPoint PPT Presentation

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In Innovative Ap Approach to o th the As Assessment of of Roa - - PowerPoint PPT Presentation

Mar 10, 2024 145 likes •368 views

Dr Richard Unitt In Innovative Ap Approach to o th the As Assessment of of Roa oad Agg Aggregates Petrographic and Metrological Analysis Follow the product from quarry to laboratory to end-use in road surface course. Measure

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SLIDE 1

Dr Richard Unitt

In Innovative Ap Approach to

  • th

the As Assessment

  • f
  • f Roa
  • ad Agg

Aggregates

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SLIDE 2

Petrographic and Metrological Analysis

  • Follow the product from quarry to laboratory to end-use in road surface course.
  • Measure microtexture (roughness) of aggregate particles
  • Examine, microscopically, the mechanisms that cause aggregate particles to wear

and weather.

  • Develop ‘fingerprints’ to ensure traceability of aggregates.
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SLIDE 3

Providing reliable quantitative measurement

  • f microtexture
  • 2D profiles of aggregate chippings not enough
  • 3D areal surface texture
  • Roughness (ISO 25178)
  • Digital Microscope
  • Leica Map Software
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SLIDE 4

Focus Stacking – Z- stacking

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SLIDE 5

Sq - Root mean square height of the scale- limited surface

  • 𝑇𝑟 =

1 𝐵 ׭ 𝐵 𝑨2 𝑦, 𝑧 d𝑦d𝑧 = Roughness

  • Measurement in microns (µm)
  • Can be measured from:
  • freshly crushed aggregate
  • aggregate artificially polished in the laboratory
  • aggregate in road-core
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SLIDE 6

Road Core

HRA + PCC PMSMA

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SLIDE 7

Roughness Measurement

  • Aggregate particles mapped for each core ‘cap’
  • Visible petrography using a stereomicroscope – grain-size, colour, identifiable

minerals

  • Transferred to digital microscope
  • Each particle measured in a specified field-of-view
  • Large topographical differences (concave/convex) removed
  • Remaining height variation = roughness
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SLIDE 8
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SLIDE 9

Experimental Work

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SLIDE 10

Major Factors Controlling Aggregate Microtexture (Roughness) and Durability

  • Grain-size
  • Mineralogy
  • Main minerals present
  • Distribution of ‘matrix’
  • Micro-structure
  • Induration/fluid infiltration
  • Degree of weathering
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SLIDE 11

Quarry Face Mapping

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SLIDE 12

Lithology

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SLIDE 13

Structure + Fluid Infiltration

0.5m

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SLIDE 14

Hand Samples and Thin Sections

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SLIDE 15

Raman Spectroscopy

  • Raman Spectroscopy –

expose mineral to a light source of specific wavelength (laser). The light interacts with molecular vibrations causing a shift in the energy

  • f the laser photons and is

recorded as a spectra.

  • Generate mineral maps of

thin sections and aggregate particles

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SLIDE 16

Equipment

  • Map rough, uneven, and curved

surfaces

  • Little or no sample preparation is

required

  • View Raman chemical images in 3D

and see both the chemistry and the topography

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SLIDE 17

Raman Mapping

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SLIDE 18

Understanding Mineralogy and Grain Relationships

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SLIDE 19

3D Imaging

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SLIDE 20

Laser Generated Topographic Maps

Provide detailed information on the microtexture (roughness)

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SLIDE 21

Research Output

  • Generate database of aggregates utilised in Ireland
  • Quarry samples
  • APM shoes
  • Road Core
  • Develop model for ranking aggregates based on their petrography
  • Ability to maintain required roughness (microtexture) over predicted lifetime
  • f surface
  • Durability – under load, chemical stability, resistance to freeze/thaw