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Short note: Project quality control

Short answer

Project quality control uses operational activities—inspection, testing, measurement—to ensure work meets standards and correct non-conformance. Techniques include inspection and testing, statistical sampling, control charts, Pareto charts, cause-and-effect diagrams, histograms, scatter diagrams, check sheets, flow charts, and quality audits.

Write a short note on project quality control and its techniques.

Project quality control

Quality control (QC) is the set of operational activities used during the project to check that the work and materials meet the specified standards, to find defects early and to correct their causes. It includes inspection, testing, measurement, and taking action on non-conformance, so that the product is acceptable to the client.

Main steps: set standards and acceptance limits, take samples and test, compare with standards, correct or reject, and record.

Techniques of quality control

  1. Inspection and testing: visual checks, measurement and laboratory/field tests (cube strength, slump, field density, bitumen content).
  2. Statistical sampling: a small sample is tested to judge the whole lot, with acceptance limits.
  3. Control charts: plot test results with upper and lower control limits over time to show whether the process is under control.
  4. Pareto chart: bar chart arranging the causes of defects in order; shows the vital few causes (80/20 rule).
  5. Cause-and-effect (fishbone) diagram: finds root causes of a defect under headings such as man, machine, material, method.
  6. Histogram: shows the distribution of measured values.
  7. Scatter diagram: shows the relation between two variables (water-cement ratio and strength).
  8. Check sheet and flow chart: record defects and show process steps.
  9. Checklists and quality audits of work stages.

✓ Answer checked by Claude Opus 5.5 (high effort)

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