In HMA production, what does the term “absorption” refer to?

In the context of Hot Mix Asphalt (HMA) production, "absorption" specifically refers to the binder retained by the aggregate. This absorption is a critical concept because it affects the performance and durability of the asphalt mixture. Aggregates have the ability to absorb asphalt binder, which can influence the overall asphalt cement content in the mix. When aggregates absorb binder, they effectively enhance the mixture's ability to adhere and improve its resistance to stripping and other forms of distress.

Understanding this concept is essential for HMA inspectors as they need to ensure that the binder content is appropriate and that the mix performs as designed. Overlooking absorption can lead to inadequate or excessive binder content, which could compromise the quality and longevity of the pavement. Thus, recognizing the importance of absorption is vital for producing high-quality HMA mixes that meet performance specifications.