Aggregate Road

[Okiryu]

Hi, for analysis of pavements, if I have the same subgrade and traffic parameters, can it be possible that an aggregate road (CBR=80)has a total lesser thickness than a flexible pavement (AC layer + base CBR 80 + subbase CBR 20)? I was expecting the opposite but my calculations indicate that the aggregate road is thinner than the flexible AC pavement. Any input will be appreciated. Thanks !

 

[geomane]

What are the pavement component thicknesses? Asphalt has a higher structural coefficient than aggregate.
Per the FDOT pavement design manual:
Superpave layer coeff = 0.44
Limerock layer coeff = 0.18

 

[Okiryu]

Thanks jmcc3265...the client just decided to keep the AC pavement...

 

[Ron]

Okiryu...that's not practical. I think you have a calculation bust or the pavement loading doesn't require the thickness you have for the flexible pavement. Is the aggregate bound with emulsion or chemical treatment?

 

[Okiryu]

Hi Ron, I used the same traffic and checked the calcs and looked okay. I will double check again but anyways, it was an interesting result. The base and subbase aggregates are classified as GM or GW, with no emulsion of chemical treatment. Very good material as we use them also as engineered granular fill.