Which statement about asphalt mixtures is true?

• A. A well designed mixture with the proper amount of asphalt binder can help reduce segregation.
• B. A poorly designed mixture with too much asphalt binder reduces segregation.
• C. Segregation is unaffected by binder content.
• D. The asphalt binder amount has no effect on segregation.

Answer: (A)

Segregation happens when the mix separates during production, transport, or placement, so some particles or layers don’t stay uniformly coated and mixed. When the asphalt binder content is designed correctly for the chosen aggregate, it coats all particles evenly and binds them into a cohesive mass. That uniform coating and cohesion help the material behave more consistently as it’s worked and compacted, reducing the tendency for the larger and smaller chunks to separate.

If the binder amount is not right, problems arise. Too much binder can lead to drainage, bleeding, and a softer mix that doesn’t hold its shape, which can promote movement and separation of particles. Too little binder can leave some particles under-coated and not well bonded, also promoting segregation. And binder content in general does influence segregation, so saying it has no effect isn’t accurate.

So the statement that a well designed mixture with the proper amount of asphalt binder can help reduce segregation is the best choice because it directly ties correct binder content to the goal of uniform coating, cohesion, and stability.