General Contractor License Site Work and Concrete 2 — Questions and Answers
Question 1: What does the term 'slump' measure in fresh concrete?
- Compressive strength after 28 days
- Workability and consistency of the mix (Correct answer)
- Air entrainment percentage
- Water-cement ratio
Correct answer: Workability and consistency of the mix
Slump measures the workability and consistency of fresh concrete by how much a standard cone of concrete settles.
Question 2: Which type of retaining wall relies primarily on its own weight for stability?
- Cantilever wall
- Gravity wall (Correct answer)
- Sheet pile wall
- Anchored wall
Correct answer: Gravity wall
A gravity retaining wall resists lateral earth pressure through its own mass and weight without reinforcement.
Question 3: What is the minimum curing period for most structural concrete under normal temperature conditions?
- 3 days
- 7 days (Correct answer)
- 14 days
- 28 days
Correct answer: 7 days
A minimum of 7 days of continuous moist curing is required for most structural concrete to achieve adequate early strength.
Question 4: During grading operations, 'cut' refers to:
- Removing vegetation before grading
- Excavating earth to lower an existing grade (Correct answer)
- Spreading imported fill material
- Compacting subgrade soils
Correct answer: Excavating earth to lower an existing grade
Cut is the excavation of existing earth to reduce the elevation to a desired grade level.
Question 5: What additive is used in concrete to reduce the water-cement ratio while maintaining workability?
- Accelerator
- Fly ash
- Water reducer (plasticizer) (Correct answer)
- Calcium chloride
Correct answer: Water reducer (plasticizer)
Water reducers (plasticizers) allow a lower water-cement ratio while keeping the mix workable, improving strength and durability.
Question 6: A percolation test is performed on a site primarily to determine:
- Bearing capacity of the soil
- Soil absorption rate for septic system sizing (Correct answer)
- Groundwater table depth
- Soil compaction density
Correct answer: Soil absorption rate for septic system sizing
A percolation (perc) test measures how quickly water drains through soil, which is essential for sizing septic drain fields.
Question 7: Which concrete placement method is most appropriate for thin slabs and areas difficult to reach by chute?
- Direct discharge from truck
- Concrete pump (Correct answer)
- Wheelbarrow placement only
- Drop chute from crane bucket
Correct answer: Concrete pump
A concrete pump can efficiently deliver concrete to thin slabs and remote or confined areas where truck chutes cannot reach.
General Contractor License Site Work and Concrete 2
What does the term 'slump' measure in fresh concrete?