What does the term "stability" refer to in aggregate base materials?

The term "stability" in the context of aggregate base materials primarily refers to the ability to maintain structural integrity under load. This characteristic is crucial for ensuring that the material can support the weight of the structures or vehicles above it without experiencing undesirable deformation or failure. A stable aggregate base provides a solid foundation, allowing for effective load distribution and minimizing the risk of settling or shifting over time. This property is pivotal in applications such as road construction or pavement design, where consistent performance under traffic loads is essential for safety and durability.

The other options, while related to the performance of materials, do not encapsulate the primary definition of stability in aggregate base materials. Retaining moisture, expanding under heat, or resisting environmental conditions can influence performance but do not specifically define the core characteristic of stability important for load-bearing capacity.