Chip Seal (Asphalt Surface Treatment/ Tar and Gravel ...- asphalt chip sealer gaskets ,Asphalt Surface Treatment (often referred to as chip seal, tar and gravel, BST-Bituminous Surface Treatment) is a widely used and very cost effective way to pave and maintain roadways, parking lots, driveways, and more.Chip Seal Treatment TypesA chip seal is a two-step process which includes first an application of asphalt emulsion and then a layer of crushed rock to an existing asphalt pavement surface. A chip seal gets its name from the “chips” or small crushed rock placed on the surface.