How can aggregates with materials subject to decomposition affect HMA mixtures?

• A. They enhance mixture flexibility
• B. They can adversely affect the mixture
• C. They improve aesthetic appearance
• D. They reduce costs significantly

Answer: (B)

Aggregates that include materials subject to decomposition can negatively impact Hot Mix Asphalt (HMA) mixtures primarily because such decomposing materials can change the physical and chemical properties of the asphalt mix. Decomposing aggregates may lead to issues like moisture susceptibility, reduced binding effectiveness, and overall structural integrity of the pavement.

When these aggregates break down over time, they can create voids or weaken the bonds within the mixture, leading to reduced load-bearing capacity and ultimately affecting the longevity and performance of the pavement. This degradation can contribute to premature cracking, raveling, or other forms of pavement distress, impacting the durability and safety of the roadway.

In contrast, the other options do not accurately reflect the implications of using decomposing materials in HMA mixes. Such materials do not enhance mixture flexibility, improve aesthetic appearance, or significantly reduce costs; rather, they introduce risks and potential expenses related to maintenance and repair.