Top 20 Common OC (Quality Control) Interview Questions and Answers for Construction and Engineering Professionals
Top 20 Common QC (Quality Control) Interview Questions and Answers
Common Questions Asked During OC Interviews
1. What is the Inspection & Test Plan (ITP)?
Answer: A mandatory item in the quality plan that guides and assures quality in a specific type of work through a sequence of quality control activities.
2. What is a Quality Control Procedure?
Answer: A document that details specific steps needed to fulfill the quality control activities outlined in the ITP.
3. What is a Quality Control Form?
Answer: A written documentation detailing a specific activity in the ITP and Quality Control Procedure.
4. What references will be found in an ITP?
Answer: Standard procedures, codes, and specification references.
5. What is a Specification?
Answer: A guideline to ensure the minimum quality standards are met.
6. What are the 4 types of inspection action points found in the ITP?
Answer: Hold, Witness, Surveillance, Review.
7. What is the minimum design compressive strength for structural concrete at 28 days curing?
Answer: 4000 psi.
8. Calibration of instruments, gauges, and test equipment should not exceed how many months?
Answer: 6 months.
9. What is the required minimum base of trench on either side of the pipeline?
Answer: 300 mm.
10. Asphalt surface regularity and thickness of the stabilized layer shall not show any deviation in excess of how many mm when tested with a 3m straight edge?
Answer: 6 mm.
11. Compaction by water jetting or flooding is only permitted if the fill material is cohesionless and freely draining. What is such material?
Answer: Sand.
12. What is the required compaction test percentage for base course materials and sub-base materials, respectively?
Answer: 95% to 100%.
13. What is the minimum required time for a moisture test after the concrete is ready for coating?
Answer: 16 hours.
14. What is the required temperature of grout on-site?
Answer: 23°C ± 3°C.
15. For pipelines, what is the maximum allowable unsupported length before backfilling?
Answer: 3 meters.
16. What is the setting time of concrete after the introduction of mixing water to the cement and aggregates?
Answer: 90 minutes or 1½ hours.
17. What is the required asphalt temperature on-site?
Answer: 139°C to 163°C.
18. Asphalt tolerance in thickness: Measurement of any core shall not be deficient by more than 10 mm or what percentage of the design thickness, whichever is less?
Answer: 15%.
19. What is the maximum allowable total dissolved solids in water used for curing concrete?
Answer: 1000 parts per million (ppm).
20. Key Takeaways for OC Interviews:
- Be familiar with ITP, Quality Control Procedures, and Forms.
- Understand specifications, standards, and codes relevant to the project.
- Know the technical requirements for materials like concrete, asphalt, and pipelines.
- Be prepared to explain inspection action points and their significance.
