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Published byIrene Mason Modified over 9 years ago
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Deterioration Unsealed Roads
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2 Gravel Earth (or Sand) * Unsealed Roads Classification * Engineered roads
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3 Unsealed Roads
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4 Unsealed Roads Deterioration
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5 Roughness Material Loss Rutting Looseness Impassability Models of Distress HDM-4
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6 Preservation Routine Off carriageway Grading Spot regravelling Periodic Regravelling Special Emergencies Winter maintenance Development Improvement s Widening Realignment Construction Upgrading New sections Unsealed Road Work Classification
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7 Roughness: Progression Effect of mechanical compaction Effect of grading Average annual roughness Steady state roughness Material Loss Unsealed Roads Models
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8 Roughness Without Compaction
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9 Grading
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10 Effect of Grading on Roughness
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11 Long term average roughness
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12 Roughness: Effect of Grading Frequency and Traffic
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13 Roughness: Effect of Terrain Type and Traffic
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14 Roughness: Effect of Environment Type and Traffic
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15 Roughness: Effect of Material Properties
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16 Material loss Effect of Rainfall and Traffic
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17 Material loss Effect of Rainfall and Terrain
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18 Road Roughness of Unsealed Roads Roughness equations valid for engineered unsealed roads with good maintenance (good drainage). Therefore: Higher rainfall yields lower roughness Higher percent of trucks yields lower roughness Earth roads (finer soils) have lower roughness than gravel roads, making difficult to evaluate regravelling works In practice, the condition of an unsealed road can be different from what is being predicted by the HDM models, specially related to the passability on the wet season
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19 Road Roughness of Unsealed Roads HDM equations for deterioration of unsealed roads are valid for engineered roads with proper drainage There is a need to understand the HDM relationships and calibrate the equations if proper drainage is not available
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