What is the maximum permissible Los Angeles abrasion loss for high-quality surface courses_______________?
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Answer: C. 30%
Explanation
For high-quality surface courses in flexible pavements, the maximum permissible Los Angeles abrasion loss is thirty percent. Surface course aggregates endure direct contact with moving tires and must resist severe mechanical wear and polishing. Restricting abrasion loss to thirty percent ensures long-term skid resistance and prevents excessive aggregate degradation. The Los Angeles abrasion test measures aggregate toughness by tumbling stone samples in a rotating steel drum. Higher abrasion losses indicate weaker mineral aggregates prone to crushing and producing excessive dust under traffic. Different pavement layers have varying aggregate quality requirements, with surface courses demanding the highest durability.
Option A suggests ten percent, which represents an extremely stringent requirement that few natural aggregates can meet. Option B proposes twenty percent, a threshold sometimes specified for heavy-duty wearing courses but more restrictive than standard. Option D lists forty-five percent, which is too high for quality surface courses and permitted only in lower base layers.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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