CSLB General Building (B)Planning and EstimatingHard
A contractor is preparing a bid for a new commercial building that requires substantial excavation. The earthwork plans specify a soil compaction requirement of 95% of maximum dry density. Which of the following tests is typically used to verify this compaction level in the field?
- AAtterberg Limits Test
- BHydrometer Analysis
- CSand Cone Test
- DProctor Compaction Test
Show answer & explanationAnswer & explanation
Correct answer: C. Sand Cone Test
The Sand Cone Test (or nuclear densometer) is a common field test used to determine the in-place density of compacted soil. This in-place density is then compared to the maximum dry density determined by a Proctor Compaction Test (performed in a lab) to verify the specified compaction level.
Why the other options are wrong
- A. Atterberg Limits tests (Liquid Limit, Plastic Limit) characterize soil plasticity, not field compaction.
- B. Hydrometer analysis is used to determine the particle size distribution of fine-grained soils, not compaction.
- D. The Proctor Compaction Test determines the *maximum* dry density in the lab, which is the target, but not the *field* verification method.
Soil Compaction Verification (Field)
The Sand Cone Test is a common field method used to determine the in-place dry density of compacted soil, which is then compared to a laboratory-determined maximum dry density to verify compaction requirements.
- Measures in-place soil density.
- Compares to lab-determined Proctor density.
- Crucial for foundation stability and settlement control.
Memory trick: Field Sand Cone, Lab Proctor's Home.