hi i'm lookinf for specification for engineering fill material. Specifically type 1 and 6f2 6f5 etc. this is all uk types so may not be appicable to a lot of people here. this is all as specified in highway works.
If you go to the highways agency website, you can download all the specifications for free. Also you may need to reference BS EN 13242, however every time it needs to specify an actual value, it refers back to the SHW.