Which statement best matches the SMA Theory description?

• A. Stone skeleton to resist permanent deformation (Stone on Stone Contact), Mortar for thick binder films
• B. Stone skeleton, One size aggregate, Thick binder films, No fine aggregate, High air voids
• C. Open Graded Friction Course uses high air voids
• D. Stone Matrix Asphalt (SMA) Theory

Answer: (D)

At its essence, SMA is built around a stone-on-stone skeleton that provides strength and rut resistance, with a rich asphalt binder forming a mortar between the aggregates to bind the structure together. The statement that explicitly names Stone Matrix Asphalt (SMA) Theory matches this description, making it the best fit. Other options describe characteristics of different mix types or misstate SMA features (for example, implying zero fines or very high air voids, which aren’t typical of SMA).