Tensar® Glasstex®

20 Years of Successful Project Use
2 Layer Composite Interlayer Product
3 Functions; Reinforcement, Stress-relief and Waterproofing
  • Glasstex stress absorbing membrane interlayers serves three functions: reinforcement (load transfer), stress relief and waterproofing
  • Controls cracking in asphalt to extend pavement life
  • One of a range of Tensar asphalt interlayer products – offering the right products for specific problems
  • Tensar has over 30 years of experience with asphalt interlayers, providing unrivalled expertise and knowledge.

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Glasstex is a low-profile composite stress absorbing membrane interlayer product comprising a grid of glass filament bundles, stitch-bonded to a non-woven paving fabric. The high-modulus glass filaments provide high absorption of stress at low strains. After being saturated with bitumen the fabric performs a sealing function. Glasstex provides reinforcement, stress relief and interlayer barrier functions, as defined by EN 15381.

Typically installed under the asphalt binder course, Glasstex’s high-stiffness grid is bonded to the asphalt, providing a reinforcement function by absorbing stress at low strain interlayer levels.

The reinforced stress absorbing membrane layer creates prolonged service life. It controls reflective cracking and mitigates longitudinal cracking caused by differential settlement between new and existing lanes on widened roads

Product Range

Available in a range of strengths

Glasstex is available in a range of tensile strengths to suit the needs of specific projects:

  • Glasstex P50
  • Glasstex P100
  • Glasstex P200

Tensar Glasstex delivers three functions

Glasstex is composed of a high-stiffness glass yarn grid stitch-bonded to a polypropylene paving fabric allowing it to perform three functions:

  • The grid absorbs stress at low strains by bonding with the asphalt overlay, providing a reinforcing effect. 
  • The fabric aids installation and together with the bitumen absorbed from the bond coat, provides a stress relief effect (stress absorbing membrane interlayer SAMI) and interlayer barrier against ingress of moisture and oxygen. 
  • The product functions of reinforcing, stress relief and interlayer barrier are as defined in EN 15381.

Stress Absorbing Membrane Installation

First, a bitumen bond coat is spray-applied to the substrate, and then Tensar Glasstex stress absorbing interlayer is simply unrolled onto the bond coat. The application rate of the bond coat is specified to ensure absorption into the interlayer fabric. Once cured, the bond coat firmly secures the interlayer in place ready for overlay with a traditional paving machine. 

While manually unrolling the interlayer is perfectly possible, the use of a specialist interlayer installation machine enables a faster installation to a high-quality.

Fully Millable and Recyclable

Unlike other interlayer systems, Glasstex mats are easily broken up by conventional milling equipment and reusable in other road projects as recycled asphalt pavement (RAP). Its main component is silica, a natural substance that is environmentally friendly.

The Benefits of Glasstex Stress Absorbing Membrane Interlayer

Glasstex FAQs

What is a stress absorbing membrane interlayer (SAMI)?

A Stress Absorbing Membrane Interlayer (SAMI) is a non-woven paving fabric composed of stitch bonded glass filament bundles. Once saturated with a top layer of bitumen or asphalt surfacing, the SAMI absorbs stresses from low strains, sealing existing cracking, preventing further reflective cracking and providing water resistance.   

What is reflective cracking in pavement?

Reflective cracks are the reappearance of existing overlaid cracks in asphalt pavement or road surfaces. Degraded asphalt needs to be overlaid with new layers to maintain integrity; cracks beneath the new layer can add additional concentrated stress to the upper surface and create a ‘reflection’ of the lower crack. Stress absorbing membrane interlayers help to prevent this.

To learn more, see our guide on types of road cracks and how to avoid them.