If a pavement mixture appears brown and dull, what issue could it reflect?

A pavement mixture that appears brown and dull is indicative of having too much asphalt binder. When there is an excess of binder in the mix, it can lead to a change in appearance, where the typical dark black color associated with well-balanced asphalt mixtures becomes dull or brownish. This is due to the larger amount of binder causing a lack of proper aggregate interlock and affecting how the light reflects off the surface.

A good HMA mixture should have a proper balance of materials, where the aggregate particles are adequately coated with asphalt while still allowing for proper density and compaction. Therefore, when the mixture appears excessively brown and dull, it suggests that the asphalt binder content has surpassed the optimal levels needed for a high-quality pavement, leading to potential performance issues in terms of longevity and usability.