An asphalt overlay geotextile, or paving fabric, is designed to hold asphaltic cement tack coat and withstand the extreme temperatures associated with paving. It functions by creating a moisture barrier between the old asphalt layer and the overlay, decreasing introduction of water into the base, reducing the effects of reflective cracking and aiding in the flexibility of the pavement.
AASHTO lists the number one cause of pavement deterioration as water beneath the pavement. A pavement saturated 10% of the time will see its lifespan decrease by 50%. According to AASHTO, upwards of 75% of water striking pavement passes through the asphalt to the base. In addition, a 1/8" crack in the surface of the asphalt will allow 97% of water striking that area of the pavement to pass through to the base.
Paving fabrics boast a 40 year documented history of increasing the life span and improving the overall performance of pavements. The main reason for the success of paving fabrics is because they substantially decrease water intrusion through the asphalt.
The nonwoven paving geotextile, combined with the tack coat and aided by pressure from the asphalt overlay, creates an asphalt saturated waterproofing and stress reducing interlayer.
Paving fabrics reduce, but do not eliminate reflective cracking. However, in the instances where a crack reflects through from the original pavement, the paving geotextile system remains in tact as a waterproof membrane, preventing water from passing through.
Finally, paving systems need to remain flexible. Research has also shown that pavement systems utilizing a paving geotextile will flex 2-3 times more than pavements without a fabric before succumbing to failure from fatigue.
Paving fabrics have proven effective under both AC overlays and chip seals. US Fabrics offers two paving fabrics. Click on the link below for a data sheets and installation instructions.