CBR Specification CBR Specification D27 (Civil/Environmental) (OP) 19 Nov 15 15:32 Can you please help me where to find specification for CBR with regards to subgrade, subbase and base course? RE: CBR Specification cvg (Civil/Environmental) 19 Nov 15 19:19 http://www.astm.org/Standards/D1883.htm RE: CBR Specification Ron (Structural) 20 Nov 15 01:41 D27...please explain a bit more about what you want. Are you looking for an acceptable CBR value for each of the courses? If so, that will depend on what your pavement design requires. As an example, if you need a certain structural number, you can achieve that with various combinations of subgrade, subbase, base and surface course layer coefficients. Each of those will have a corresponding CBR value, except for the surface course. Generally, a pavement is built from the bottom up. The subgrade is strong because of its high thickness, even though a lower CBR is used in the subgrade. Each layer is correspondingly similar. RE: CBR Specification D27 (Civil/Environmental) (OP) 20 Nov 15 09:36 @ Ron, so you're saying there are no standard specification for CBR values for those materials, specs shall be base as per project pavement requirements? RE: CBR Specification cvg (Civil/Environmental) 20 Nov 15 14:05 certain agencies may have standard requirements for minimum CBR. otherwise it is the pavement designers responsibility to design the pavement structural section.