What is the effect of thermal expansion on asphalt pavements?

The effect of thermal expansion on asphalt pavements primarily involves the potential for cracks to develop due to movement and stress within the pavement structure. As temperatures rise, asphalt can expand, which might lead to increased internal pressure within the pavement layers. When this expansion occurs without enough room for the materials to flex in response, it can create stress points that ultimately lead to cracking. These cracks can compromise the integrity of the pavement, allowing water infiltration and potentially causing further damage.

Conversely, the other choices do not accurately describe the impact of thermal expansion. For example, while flexibility is important for asphalt, thermal expansion can actually lead to rigidity and cracking rather than increased flexibility. The bonding of aggregates is more dependent on the mixing process and the quality of materials rather than thermal expansion, and drainage capabilities are influenced by the design and slope of the pavement rather than temperature changes alone.