My local racing group got permission to dig up and replace our racing surface at the "track" we race at. The surface was basically what was left after removing the grass. We got a local company to donate material for the track and we were told it was going to be mostly clay. Unfortunately, its more like 90% silt and sand and 10% some kind of weird blue clay. (I know, shame on us for not looking at the material before taking delivery of it). Does anyone have any experience or suggestion on what i can mix in to this type of material to help it bind together better? The ruts and bumps we create during a race become unmanageable. Any help or ideas would be appreciated.