Granular Sealing and Tack Coat

Granular sealing is a sprayed asphalt emulsion, cutback or tall oil pitch designed to seal and protect road shoulders from water penetration. The emulsion is sprayed and penetrates the shoulder to lock it in place and to promote water run off. It is beneficial to use granular sealing around guardrail bases to prevent water erosion and ensure road structure stability.

A prime coat is a single application of either a specially formulated asphalt emulsion or a low-viscosity asphalt cutback. Their primary functions are to penetrate quickly into the granular surface and bind the material together, to partially waterproof the granular surface to prevent water erosion, to provide a temporary riding surface prior to overlay or seal coating and to provide a bond between the existing surface and the new wearing surface.

The asphalt emulsions used as prime coats typically contain a combination of asphalt and specially engineered agents to aid in penetrating the granular surface, while binding the aggregate particles to achieve stabilization.

A tack coat is the application of an asphalt emulsion between an existing asphalt or portland cement concrete surface and a new asphalt overlay or patching. The tack coat provides an enhanced bond between layers, preventing slippage and ensuring sound structural performance.