What is asphalt used for in highway construction?

Asphalt plays a crucial role in highway construction primarily as a binder in roadway surfaces. This means it is utilized to hold together the aggregate particles, which include sand, gravel, and crushed stone, creating a stable and durable pavement. The binding properties of asphalt allow it to provide flexibility and resilience, which are essential for withstanding the stresses and loads imposed by vehicular traffic.

The use of asphalt contributes to the longevity of road surfaces, as it enhances their resistance to deformation, cracking, and weather-related damage. It also aids in providing a smooth driving surface, which is important for vehicle safety and comfort. Without asphalt as a binder, the quality and durability of road surfaces would significantly diminish, leading to increased maintenance needs and decreased longevity of the infrastructure.

The other options mentioned do not capture the primary function of asphalt in highway construction, which is focused on its binding capabilities rather than aesthetics, soundproofing properties, or reinforcement for concrete.