Installation Guideline: Asphalt Overlay Fabric
- This document contains information consistent with generally accepted practices of identifying, handling, storing and installing geosynthetic material. Failure to follow these guidelines may result in the failure of the geotextile in a properly designed application.
- The geotextile will be rolled on cores having strength sufficient to avoid collapse and damage from normal use. Each individual roll will be wrapped with a plastic covering to protect the fabric from damage during shipping and handling and will be identified with a durable label clearly visible on the outside of the wrapping of the roll.
- While unloading or transferring the geosynthetic from one location to another, take care to prevent damage to the wrapping, core, label and the geotextile.
- During storage, elevate the geotextile off the ground ensuring that it is adequately covered with a tarpaulin or opaque plastic and protected from moisture, ultraviolet radiation, chemicals that are strong acids or bases, temperatures in excess of 140ºF and animal destruction.
- Mechanical or manual laydown equipment should be capable of laying down the geotextile fabric smoothly.
- For large distances, the geotextile fabric can be installed with a mechanical unit that is mounted on the front bucket of a tractor or backhoe.
- Stiff bristle brooms or squeegees to smooth the geotextile fabric, scissors or blades to cut the geotextile and brushes for applying asphalt sealant are required.
- Prepare the surface so that no damage to the geotextile occurs.
- Thoroughly clean the old pavement by removing all dirt, water, oil and foreign materials.
- Fill all cracks with an asphaltic cement slurry. Fill very large cracks (1/8" or larger) and potholes with a full depth hot mix.
Sealing & Applying Tack Coat
- Uncut asphalt cement is the preferred sealant to impregnate and seal the geotextile, as well as bond it to the pavement. Uncut asphalt cement is preferred because it develops adhesive strength quicker.
- Cut-back grade asphalt or emulsions which contain solvents are not recommended as tack coat.
- The application rate of the tack coat depends on the porosity of the existing pavement. Apply the tack coat at a distribution range of 0.20 gal/sy to .30 gal/sy.
- Use a calibrated distributor truck to assure the specified tack rate.
- Apply the tack coat 6 inches wider than the geotextile.
- If emulsions are used, allow any water to evaporate before applying the geotextile.
- Apply the tack coat at or above the recommended application temperatures of 140ºF for asphaltic cement and 160ºF for heavier grade emulsions.
- The tack coat temperature should not exceed 325ºF.
- Air and pavement temperatures during installation should be at least 50ºF and rising for asphaltic cement or 60ºF and rising for heavier grade emulsions.
- Place the geotextile with the untreated (fuzzy) side against the existing pavement while the tack coat is still tacky. Calendared side is facing up.
- Make sure the geotextile is smooth and straight.
- For sharp corners or curves, slice the geotextile and overlap ends in the direction of the paving operation.
- When a transverse joint is required, overlap the geotextile 4 to 6 inches in the direction of the paving operation.
- Overlap longitudinal joints 2 to 4 inches.
- Apply additional tack coat to any joints to insure proper bonding.
- After geotextile placement, proceed with standard paving operation.