CCI Construction Materials & Methods 3 — Questions and Answers
Question 1: A concrete mix design calls for a water-to-cement (w/c) ratio of 0.45. If 400 lbs of cement is used per cubic yard, how much water (in lbs) is required?
- 160 lbs
- 180 lbs (Correct answer)
- 200 lbs
- 220 lbs
Correct answer: 180 lbs
Water weight = w/c ratio × cement weight = 0.45 × 400 = 180 lbs of water per cubic yard.
Question 2: Which type of pile is most appropriate when driving through soft soils to reach a hard bearing stratum?
- Friction pile
- End-bearing pile (Correct answer)
- Batter pile
- Compaction pile
Correct answer: End-bearing pile
End-bearing piles transfer structural loads through weak soils to a firm layer such as rock or dense gravel at the pile tip.
Question 3: In roofing, what does 'R-value' measure?
- Reflectivity of the roofing surface
- Thermal resistance of insulation (Correct answer)
- Compressive strength of rigid board
- Wind uplift resistance
Correct answer: Thermal resistance of insulation
R-value is a measure of thermal resistance — the higher the R-value, the greater the insulating effectiveness of the material.
Question 4: What is the function of 'admixture' Type C (accelerator) in concrete?
- Delays set time in hot weather
- Speeds up hydration to allow earlier form removal (Correct answer)
- Reduces water content needed
- Improves sulfate resistance
Correct answer: Speeds up hydration to allow earlier form removal
Accelerating admixtures speed up the hydration of cement, increasing early strength gain and allowing earlier form stripping, especially useful in cold weather.
Question 5: When inspecting structural lumber, the designation 'No. 2 & Btr' means the lumber is:
- Only No. 2 grade material
- No. 2 grade or higher quality (Correct answer)
- Second growth timber only
- A secondary structural grade below No. 1
Correct answer: No. 2 grade or higher quality
'No. 2 & Better' (No. 2 & Btr) means the lumber meets at least No. 2 grade standards and may include No. 1 or Select Structural grade material.
Question 6: In welding inspection, what does the term 'undercut' describe?
- A weld that is lower than the required throat size
- A groove melted into base metal adjacent to the weld toe left unfilled (Correct answer)
- Porosity beneath the weld surface
- Incomplete fusion in the root pass
Correct answer: A groove melted into base metal adjacent to the weld toe left unfilled
Undercut is a groove or channel burned into the base metal at the weld toe that is not filled by weld metal, creating a stress concentration.
Question 7: What ASTM standard governs the specification for deformed and plain steel bars for concrete reinforcement?
- ASTM A36
- ASTM A615 (Correct answer)
- ASTM A325
- ASTM A572
Correct answer: ASTM A615
ASTM A615 is the standard specification for deformed and plain carbon-steel bars for concrete reinforcement, covering grades 40, 60, and 80.
CCI Construction Materials & Methods 3
A concrete mix design calls for a water-to-cement (w/c) ratio of 0.45.
If 400 lbs of cement is used per cubic yard, how much water (in lbs) is required?