Class 6A material is a selected and well-graded granular fill, that is used in highway construction. The grading requirement for this material are defined in Series 600 Earthwork of the Specification for Highway Works.
This is the only aggregate within the specifications that can be used underwater, meaning it has quite specific uses.
Its composition primarily consists of crushed stone particles, with a size of 500mm. Although there are some smaller particle sizes passing through.
This includes a wide range of materials such as natural gravel, natural sand, crushed gravel, crushed rock, crushed concrete, chalk, well burnt colliery spoil and recycled materials.
If it’s being used within highway construction it must meet the specifications laid out in Series 600 Earthwork of the Specification for Highway Work.
Compliance with these specifications is important in ensuring the durability, safety and reliability of highways for years to come.
Table 6/2: Grading Requirements for Acceptable Earthwork Materials
Table 6/5: Imported Onto Site Grading Requirements for Class 6 Acceptable Earthwork Materials