NASCLA Commercial General Building Contractor Exam — All Questions
2 questions
How many cubic yards of concrete are needed for a slab 20 ft by 30 ft placed 6 inches thick (before any waste factor)?
- a.11.1 cy✓
- b.3.7 cy
- c.22.2 cy
- d.100 cy
Convert thickness to feet (6 / 12 = 0.5 ft), then volume = (20 x 30 x 0.5) / 27 = 300 / 27 = 11.1 cubic yards. There are 27 cubic feet in a cubic yard, so dividing by 27 converts cubic feet to cubic yards.Concrete volume: (L x W x thickness) / 27
On a commercial pour, the crew measures the concrete's slump before placement. What does the slump test primarily indicate?
- a.The compressive strength at 28 days
- b.The chloride-ion content
- c.The consistency and workability (relative fluidity) of the fresh concrete✓
- d.The air-entrainment percentage
The slump test measures the consistency and workability of fresh concrete. It does not measure strength, which is verified by breaking cured cylinders (typically at 28 days per ACI 318). A slump outside the specified range signals a mix or water problem before the concrete is placed.ACI 318 / concrete slump test