CTQP Earthwork Construction Inspection 2 — Questions and Answers
Question 1: What piece of equipment is commonly used to compact cohesive soils in earthwork operations?
- Smooth drum vibratory roller
- Sheepsfoot or padfoot roller (Correct answer)
- Pneumatic tire roller
- Plate compactor
Correct answer: Sheepsfoot or padfoot roller
Sheepsfoot and padfoot rollers are most effective for compacting cohesive (clay) soils because their feet penetrate and knead the soil.
Question 2: What is the purpose of a subgrade proof roll in earthwork inspection?
- To apply waterproofing to the subgrade surface
- To identify soft or unstable areas in the prepared subgrade (Correct answer)
- To measure the thickness of the subgrade layer
- To compact the top 6 inches of subgrade
Correct answer: To identify soft or unstable areas in the prepared subgrade
A proof roll uses a heavily loaded tandem-axle dump truck driven across the subgrade to identify soft, pumping, or unstable areas that need remediation.
Question 3: What is 'muck excavation' as defined under FDOT pay items?
- Excavation of any material below the water table
- Excavation and removal of organic, unsuitable material (Correct answer)
- Excavation performed with specialized underwater equipment
- Excavation of rock material in wet conditions
Correct answer: Excavation and removal of organic, unsuitable material
Muck excavation is the removal of organic or otherwise unsuitable material from below the ground surface, typically replaced with suitable fill.
Question 4: When inspecting a fill slope, what ratio does '3:1' indicate?
- 3 feet vertical for every 1 foot horizontal
- 1 foot vertical for every 3 feet horizontal (Correct answer)
- 3% grade over 1 mile
- 3 tons of compaction force per 1 square foot
Correct answer: 1 foot vertical for every 3 feet horizontal
A 3:1 slope means 3 feet horizontal for every 1 foot vertical, and is a common slope for embankment side slopes in FDOT projects.
Question 5: Which soil classification system is most commonly referenced in FDOT earthwork specifications?
- USCS (Unified Soil Classification System)
- AASHTO Soil Classification System (Correct answer)
- USDA Textural Classification
- ASTM D 2487
Correct answer: AASHTO Soil Classification System
FDOT references the AASHTO soil classification system, which groups soils A-1 through A-7 based on gradation and Atterberg limits.
Question 6: What document controls the acceptable limits for earthwork on an FDOT project?
- The Standard Specifications for Road and Bridge Construction (Correct answer)
- The geotechnical investigation report only
- The contractor's quality control plan
- The environmental permit
Correct answer: The Standard Specifications for Road and Bridge Construction
FDOT's Standard Specifications for Road and Bridge Construction (and applicable special provisions) govern all earthwork requirements including material acceptance and compaction.
CTQP Earthwork Construction Inspection 2
What piece of equipment is commonly used to compact cohesive soils in earthwork operations?