February 1, 2020 Thesis Open Access

ZEKARIYAS MUSSIE AMANU

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{
  "DOI": "10.20372/nadre:2536", 
  "author": [
    {
      "family": "ZEKARIYAS MUSSIE AMANU"
    }
  ], 
  "issued": {
    "date-parts": [
      [
        2020, 
        2, 
        1
      ]
    ]
  }, 
  "abstract": "<p>Asphalt Concrete mixtures were characterized by one of mechanistically modeling<br>\ntechnique, inherent anisotropy of the material. The performance of AC<br>\nmixtures is influenced by the arrangement of aggregates and their associated<br>\nair voids. The main objective of this study to analyze aggregate orientation<br>\nand evaluates inherent anisotropy in AC mixtures using X-ray CT images<br>\nby means of microstructure parameter. There are three AC mixture designs:<br>\ncoarse graded CMHB Type C, gap graded PFC and fine graded Superpave<br>\nType C AC mixtures. They are prepared with hard limestone aggregate and<br>\ncompacted with SGC, having a PG 76-22 modified binder.<br>\nDigital image processing algorithm is adopted for this study to process X-ray<br>\nCT scanned images and effectively separate the connected or overlapping aggregates<br>\nusing MATLABr 2018b, image processing toolbox. It includes for<br>\nboth coarse and fine aggregate particles ranging from 1.18 mm to 19 mm. The<br>\naggregate orientation, size and area can be used to define internal structure<br>\nparameters (i.e., modified Vector magnitude) to evaluate inherent anisotropy<br>\nof AC mixtures.<br>\nAggregates have three dominant average orientations having 20% of the aggregates<br>\nhas an inclination angle between (-10o-10o), 65% of the aggregates<br>\nhave an inclination angle between (-45o-45o) and 15% of aggregates have<br>\nan inclination angle between (-45o-90o) for three AC mixtures. Small inclination<br>\nangle indicates the aggregates lies flat in the horizontal direction that<br>\nis perpendicular to the compaction direction. In addition, statistical analysis<br>\nwas performed for AC mixtures within AC layers. It results, aggregate<br>\norientation varies within AC layers. Variation of aggregates orientation is<br>\nperformed using Scheffe multi-comparison test.</p>", 
  "title": "ANALYSIS OF INHERENT ANISOTROPY IN ASPHALT CONCRETE MIXTURES", 
  "type": "thesis", 
  "id": "2536"
}