Abstract
Gravel roads may fail due to a number of mechanisms. In this paper, the researchers are only considering those cases in which the road was constructed with aggregates that met or were predicted to meet the specifications but failed due to either unforeseen changes in the materials or due to unrecognized contaminants in the materials. These cases can be divided into three types: failures due to low permeability caused by the presence of plastic or micaceous fines; failures due to low permeability caused by the presence of bacteria and algae; and failures due to breakdown of the coarse aggregate to the sand sizes. (A)