Evaluating Penetration of Prime Coats Produced with Kerosene and Bio-Solvent

The prime coat is used to create a layer of bitumen to seal the base layer surface in road pavements, protecting under-layers from water intrusion, binding the surface material, enhancing adhesion between unbound and asphalt layers, and preventing slippage between them. The presence of the solvent improves penetration of prime coat material through facilitating the capillary action. Because of environmental aspects, in this study, the cationic emulsion is produced with two different solvents, namely Kerosene and bio-solvent, with three different quantities, 0, 7, and 12 percent by emulsion. Penetration of emulsions in compacted base layer material was evaluated in dry and wet condition. The results showed that the amount of solvent had a remarkable influence in the penetration of emulsion and the solvent-containing emulsions had better penetration than emulsion without solvent. Also, aggregate type and their moisture content had a significant effect on the penetration of emulsion, so that the penetration in wet calcareous aggregates was more than dry calcareous and wet and dry siliceous aggregates.