about cbr test

[civilQ]

hello
what is the purpose of using a filter paper in cbr test and is it correct to use the modified proctor molds (152 mm dia 115 mm height ) for cbr without a spacer disk since it gives same sample volume ?

 

[ih8xc]

If you don't use the spacer disks how would you place the surcharge weights during soaking or during the test (pushing the plunger)?

 

[civilQ]

i can use the collar