Is sampling the HMA mix directly behind the paver allowed by the AASHTO standard?

• A. Yes, it is allowed
• B. No, it is prohibited
• C. Only with special permission
• D. It depends on the project specifications

Answer: (B)

The AASHTO standard typically does not allow for sampling of the Hot Mix Asphalt (HMA) mix directly behind the paver. This is due to the potential for ongoing adjustments and variability in the mix as it is being laid down, which can result in discrepancies in sampling. Sampling at this stage might not accurately reflect the final product, as it could capture variations that have not fully settled or integrated into the surface.

By prohibiting sampling directly behind the paver, the focus is on ensuring that sampling is done at a stage where the material is more consistent and representative of the mix that will ultimately be compacted and used. This practice helps in achieving reliable testing results that are crucial for quality control and assurance in pavement construction.

The other options suggest either conditional permissibility or allowance under certain circumstances, but they do not align with the strict guidelines which prioritize accuracy and quality in sampling processes.