This method is applicable to the determination of moisture in asphalt mixtures as well as aggregate.

This method is applicable to the determination of moisture in asphalt mixtures as well as aggregate.

• A. True
• B. False
• C. Not applicable
• D. Sometimes

Answer: (B)

Moisture testing methods must account for what the sample is made of. An oven-drying (loss-on-drying) approach works well for aggregates because you’re mostly removing water at a temperature that won’t affect the mineral material. But asphalt mixtures contain a binder that reacts to heat. When you bake an asphalt mixture, the binder can soften, vaporize, or drain, and other heat-related changes can occur. Those changes change the sample’s mass in ways that aren’t just due to moisture, so the measured “moisture content” would be inaccurate. Because of that, the same method cannot be relied on for asphalt mixtures as for aggregate. You would need a method specifically suitable for asphalt mixtures (or for measuring moisture in the aggregate portion within the mixture) to get a valid result.

Moisture testing methods must account for what the sample is made of. An oven-drying (loss-on-drying) approach works well for aggregates because you’re mostly removing water at a temperature that won’t affect the mineral material. But asphalt mixtures contain a binder that reacts to heat. When you bake an asphalt mixture, the binder can soften, vaporize, or drain, and other heat-related changes can occur. Those changes change the sample’s mass in ways that aren’t just due to moisture, so the measured “moisture content” would be inaccurate.

Because of that, the same method cannot be relied on for asphalt mixtures as for aggregate. You would need a method specifically suitable for asphalt mixtures (or for measuring moisture in the aggregate portion within the mixture) to get a valid result.