What is true about using RAP low in moisture in HMA mixtures?

• A. It can be used in smaller amounts.
• B. It can be used in greater amounts.
• C. It is ineffective for mixing.
• D. It should not be used at all.

Answer: (B)

Using Reclaimed Asphalt Pavement (RAP) that is low in moisture in Hot Mix Asphalt (HMA) mixtures allows for a greater percentage of RAP to be incorporated effectively. When RAP is dry, it has a lower potential for introducing excess moisture into the mix, which can negatively impact the performance and durability of the pavement. The presence of moisture in RAP can cause issues such as stripping, which leads to a weak bond between the binder and aggregates, ultimately compromising the structural integrity of the pavement.

By using lower moisture RAP, asphalt producers can achieve a better overall quality within the HMA mixture. This enhanced quality enables the incorporation of a higher percentage of RAP without fear of the adverse effects that moisture could cause. Therefore, it allows for better resource utilization, which is a significant benefit in terms of both cost and environmental sustainability.