The pipe backfill in the cover zone should be compacted to a density of at least 95% of the Standard Proctor maximum density when the cover height below the bottom of base under asphalt, below concrete pavement, or below unpaved ground does what?

The pipe backfill in the cover zone should be compacted to a density of at least 95% of the Standard Proctor maximum density when the cover height below the bottom of base under asphalt, below concrete pavement, or below unpaved ground does what?

• A. Exceeds 15 inches
• B. Does not exceed 5 inches
• C. Is exactly 15 inches
• D. Is not specified

Answer: (A)

When backfilling around a pipe, how densely you compact the soil depends on how much cover sits above it. A thicker cover puts more load on the pipe area, so you require a denser fill to resist settlement and support pavement properly. The specification uses 15 inches as the cutoff: if the cover height below the base under asphalt, below concrete pavement, or below unpaved ground is greater than 15 inches, you must compact the pipe backfill to at least 95% of the Standard Proctor maximum density. The other options don’t match this threshold.

When backfilling around a pipe, how densely you compact the soil depends on how much cover sits above it. A thicker cover puts more load on the pipe area, so you require a denser fill to resist settlement and support pavement properly. The specification uses 15 inches as the cutoff: if the cover height below the base under asphalt, below concrete pavement, or below unpaved ground is greater than 15 inches, you must compact the pipe backfill to at least 95% of the Standard Proctor maximum density. The other options don’t match this threshold.