United States
Hong KongConcrete
Six of 115 scored questions covering formwork and shoring, reinforcing steel placement and cover, mixing and placing, and curing and weather concreting. The safety provisions overlap with General Requirements.
Six questions. Worth preparing properly because the numbers are specific and lookup-friendly.
The four subtopics
- Formwork, shoring and reshoring
- Reinforcing steel - placement, cover and splices
- Mixing, placing, consolidation and joints
- Curing, testing and cold and hot weather concreting
The numbers
| Item | Figure |
|---|---|
| Standard test age | 28 days |
| Common specified strength | 3,000 pounds per square inch |
| Cover against earth | 3 inches |
| Cover, formed and exposed to weather | 2 inches with larger bars |
| Cold weather threshold | 40 degrees Fahrenheit |
| Hot weather threshold | 90 degrees Fahrenheit |
| Common minimum moist curing | 7 days |
Learn cover as a pair. Three inches against earth, two inches formed and exposed - the difference is whether concrete was cast directly against the ground.
Protruding reinforcing steel must be guarded to eliminate the impalement hazard, under 29 CFR 1926.701(b). It sits in the concrete category and the answer is in the OSHA standards, which is exactly the kind of cross-reference that costs time if you have not thought about it.
Formwork removal
Only when the concrete has gained sufficient strength, determined under a plan prepared by a qualified person, at 29 CFR 1926.703(e).
Note qualified rather than competent. The distinction is tested.
The slump test
Measures workability, not strength. Candidates who half-remember it as a strength test lose the question, and it is asked.
Common questions
How many concrete questions are on the NASCLA exam?
6 of the 115 scored questions.
At what age is concrete strength tested?
28 days is the standard age for compressive strength testing.
What concrete cover is required against earth?
3 inches where cast against and permanently exposed to earth, and 2 inches for formed surfaces exposed to weather with larger bars.
What does the slump test measure?
Workability, not strength.
When may formwork be removed?
When the concrete has gained sufficient strength, determined under a plan by a qualified person, at 29 CFR 1926.703(e).