Class 6B material is a grade of material that is categorised within series 600 Earthworks of the Specification for Highway Work. It is a selected, well-graded granular fill material intended as a starter layer
You should place the material as the first layer or layers of fill above the existing ground level, or any required ground improvement measures. Before compaction, you need to lay it in layers using a crawler tractor of at least 15 tonnes. After compaction, if there are any voids remaining, you must fill them with an approved grade of granular material. This ensures that all surface voids are properly filled before adding the subsequent layer or commencing capping and sub-base construction.
This wide range of materials can include natural gravel, natural sand, crushed gravel, crushed rock, crushed concrete, chalk, well burnt colliery spoil, slag and recycled aggregates
When class 6B material is employed for highway construction, it is imperative to adhere to the grading requirements outlined in Series 600 Earthwork of the Specification for Highway Work. These specifications ensure the longevity and structural integrity of highways.
Below are the specification.
Table 6/2: Grading Requirements for Acceptable Earthwork Materials
Table 6/5: Imported Onto Site Grading Requirements for Class 6 Acceptable Earthwork Materials