Construction QC/QA Representative Samples 1

Quality Control / Quality Assurance

Obtaining a representative sample

Senior/Graduate

HMA Course

Construction QC/QA Representative Samples 2

Sample Size

• Mixture Component Variability

• Confidence Level

• Error or Bias From True Value

• Effect on Performance

Construction QC/QA Representative Samples 3

Frequency of Sampling/Testing

• Mixture Production Variability

• Effect on Performance

• Previous History

• Compliance With Specifications

Construction QC/QA Representative Samples 4

SAMPLING

• Preliminary Investigation of the Potential Source

• Control of Product at the Source of Supply

• Control of Operations at the Site of Use

• Acceptance or Rejection of Material

Construction QC/QA Representative Samples 5

SIZE AND NUMBER OF

SAMPLES

D 3665 Random Sampling of Construction Materials

E 105 Probability Sampling of Materials

E 122 Choice of Sample Size to Estimate the Average Quality of a Lot or Process

E 141 Acceptance of Evidence Based on the Result of Probability of Sampling

Construction QC/QA Representative Samples 6

SAMPLE SIZE

Nominal

Maximum Size Minimum Mass, lbs.

No. 8 4

No. 4 4

3/8 8

1/2 12

3/4 16

1 20

Construction QC/QA Representative Samples 7

Types of samples to be taken

• Aggregate

• Asphalt binder

• HMA mixture