CSLB C-27 Landscaping ContractorSite Preparation and DrainageMedium
A C-27 contractor is preparing a site for a new gravel pathway that will experience moderate foot traffic. To ensure stability and prevent settling, what is the minimum relative compaction percentage generally required for the subgrade beneath a gravel pathway?
- A95% relative compaction
- B100% relative compaction
- C90% relative compaction
- D85% relative compaction
Show answer & explanationAnswer & explanation
Correct answer: C. 90% relative compaction
For gravel pathways experiencing moderate foot traffic, a minimum of 90% relative compaction for the subgrade is typically required. This provides sufficient stability to prevent settling and maintain the pathway's integrity over time.
Why the other options are wrong
- A. 95% relative compaction is often specified for heavier load areas like driveways or building foundations.
- B. 100% relative compaction is difficult to achieve and usually only required for very critical structures or pavement under heavy loads.
- D. 85% relative compaction is generally too low for a pathway and could lead to significant settling.
Subgrade Compaction (Gravel Pathway)
The minimum relative compaction percentage required for the subgrade beneath a gravel pathway, typically 90%, to ensure stability and prevent future settling.
- Prevents differential settling of the pathway.
- Increases load-bearing capacity of the subgrade.
- Ensures the longevity and evenness of the pathway surface.
- Achieved through mechanical compaction with appropriate moisture content.
Memory trick: Ninety percent for paths, so they last.