Grain size specifications of sand for highway pavement

Highway pavement sand, also known as aggregate sand, is a crucial component of the roadway structure. It is used in various layers, including the base, subbase, and surface courses, to provide strength, stability, and drainage capabilities. To ensure optimal performance, the sand used in highway pavement must meet specific grain size specifications.

The grain size specifications of sand for highway pavement typically fall within the following ranges:

Coarse Sand: Coarse sand, also known as CS, is characterized by its relatively large particle sizes. The grain sizes for coarse sand typically range from 2.36 to 4.75 mm (0.09 to 0.19 inches) in diameter. This type of sand is commonly used in the base and subbase layers of the pavement structure, where its primary function is to provide structural support and drainage.

Medium Sand: Medium sand, or MS, has particle sizes that are smaller than coarse sand but larger than fine sand. The grain sizes for medium sand typically range from 1.18 to 2.36 mm (0.046 to 0.09 inches) in diameter. This type of sand is commonly used in the lower layers of the pavement structure, such as the subbase and base courses, to provide strength and stability.

Fine Sand: Fine sand, also known as FS, has the smallest particle sizes of the three types. The grain sizes for fine sand typically range from 0.60 to 1.18 mm (0.024 to 0.046 inches) in diameter. This type of sand is commonly used in the upper layers of the pavement structure, such as the surface course, to provide a smooth ride quality and improve skid resistance.

The specific grain size specifications for sand in highway pavement can vary depending on the local climate, soil conditions, and traffic loads. Therefore, it is important for contractors and engineers to consult with local departments of transportation or highway agencies to determine the appropriate grain size specifications for the specific project at hand.

In conclusion, the grain size specifications of sand for highway pavement typically fall within the ranges of coarse sand (2.36 to 4.75 mm), medium sand (1.18 to 2.36 mm), and fine sand (0.60 to 1.18 mm). The appropriate grain size specifications should be determined based on the specific requirements of the project and the local highway agency's guidelines.