SIGMA supplies fiberglass geogrid warp-knitted from alkali-free glass fibre rovings and coated with modified bitumen. It is laid between asphalt layers, where its very high modulus and very low elongation intercept and redistribute the horizontal stress that drives a reflective crack up into a new overlay. Glass fibre softens above 1000 °C, so the grid survives hot-mix placement without losing strength — the reason an asphalt geogrid is made of glass rather than plastic. Standard EGA grades run 25-25 to 120-120 kN/m at 25.4 × 25.4 mm mesh in 1–6 m widths, with a self-adhesive EGAA range for jobs where nails and tack coat are impractical.
A fiberglass geogrid is not a soil reinforcement product. It is placed inside the pavement structure — between the milled or existing surface and a new asphalt layer — to deal with cracking rather than with bearing capacity. When an old crack or joint opens and closes under traffic and temperature, the movement concentrates stress at one line in the new overlay and drives a reflective crack straight to the surface, often within two or three seasons. The grid sits in that stress path, picks the load up in tension and spreads it sideways over a much wider band of asphalt, so no single section reaches its cracking strain. That is the whole purpose of an asphalt geogrid, and it is why the product is specified by modulus rather than by aperture size.
Plastic geogrids are the right answer under a road, not inside one. Two properties decide it. First, strain: asphalt cracks at well under 1% strain, so a reinforcement layer only helps if it carries load at a strain the asphalt can still tolerate. Glass fibre reaches its rated breaking strength at ≤ 4% elongation, while polymer grids need far more stretch before they take meaningful load — by then the overlay has already cracked. Second, heat: hot-mix asphalt is placed at roughly 150 °C and compacted immediately. Glass fibre softens above 1000 °C and is unaffected; polyolefin grids soften in that range. Together these two facts make glass fiber geogrid the standard material for geogrid asphalt reinforcement, and keep our biaxial geogrid and uniaxial geogrid in their own roles below the pavement.
The standard EGA range runs 25-25, 30-30, 40-40, 50-50, 60-60, 80-80, 100-100 and 120-120 kN/m, equal in warp and weft, all at ≤ 4% elongation at break. It is fixed with nails or staples over a tack coat before paving. The self-adhesive EGAA range carries the same strength ladder with a pressure-sensitive adhesive backing and release film, so the grid can be rolled out and pressed down without nails on smaller resurfacing jobs. Note that the self-adhesive range is published without a 60-60 grade — that is how the material is made, not a gap in our listing, so specify 50-50 or 80-80 in EGAA unless we confirm otherwise for your order. One mill quotes glass fibre grids up to 400 kN/m; grades above 120 kN/m are quote-on-request against a mill certificate rather than stock items.
The surface is milled or cleaned, potholes and wide cracks are patched, and a bitumen tack coat is sprayed at the rate the job specifies. The roll is laid flat with the machine direction along the paving direction, tensioned by hand so there are no waves, and overlapped roughly 100–200 mm at the seams; transverse joints are lapped in the direction of paving so the screed cannot lift an edge. Paving follows the same day. Because the modified bitumen coating melts into the tack coat and the new mix, the grid ends up embedded in mastic rather than lying loose — that bond is what lets geogrid pavement reinforcement transfer stress at all. A minimum 40 mm overlay is normal practice over the grid; thinner surfacings do not confine it properly.
The usual case is an asphalt overlay on a pavement that is structurally sound but cracked — fatigue-cracked highway, an old concrete slab road being surfaced, or a widening where the new and old sections will move differently. Airport aprons, port yards and bus lanes use the higher grades because loads are heavy and slow. Municipal resurfacing uses the lighter grades where overlay thickness is capped by kerb heights. Where the problem is the subgrade rather than the surface, the answer is a base-course grid or a separation layer instead: see steel-plastic geogrid and polyester geogrid for reinforcement, or nonwoven geotextile and woven geotextile for separation under the base.
We produce fiberglass geogrid across the full grade range, warp-knitting alkali-free glass fibre roving and coating it with modified bitumen on our own coating lines. That means we quote across grades and mesh sizes rather than pushing a single standard build. Mesh is available at 12.7, 25.4 or 50 mm, roll widths at 2, 4 and 6 m within a 1–6 m range, and strength, width and mesh can be customised to order. Roll length and mass per unit area are not published for this line and are confirmed per order with the mill. Send the required strength, mesh, width and quantity — plus whether you want standard or self-adhesive — and we will come back with an ex-works price and the current test certificate. The full range sits in our geosynthetics catalogue.
Fiberglass geogrid — standard EGA range and self-adhesive EGAA range. Values verbatim from the source datasheet; roll length and mass per unit area are not published for this line.
| Property | Unit | 25-25 | 30-30 | 40-40 | 50-50 | 60-60 | 80-80 | 100-100 | 120-120 |
|---|---|---|---|---|---|---|---|---|---|
| EGA — Breaking strength, warp | kN/m ≥ | 25 | 30 | 40 | 50 | 60 | 80 | 100 | 120 |
| EGA — Breaking strength, weft | kN/m ≥ | 25 | 30 | 40 | 50 | 60 | 80 | 100 | 120 |
| EGA — Elongation at break (warp / weft) | % ≤ | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| EGA — Mesh size | mm | 25.4 × 25.4 | ← | ← | ← | ← | ← | ← | ← |
| EGA — Roll width | m | 1–6 | ← | ← | ← | ← | ← | ← | ← |
| EGAA (self-adhesive) — Breaking strength, warp / weft | kN/m ≥ | 25 | 30 | 40 | 50 | — | 80 | 100 | 120 |
| EGAA (self-adhesive) — Elongation at break | % ≤ | 4 | 4 | 4 | 4 | — | 4 | 4 | 4 |
| EGAA (self-adhesive) — Mesh size | mm | 25.4 × 25.4 | ← | ← | ← | — | ← | ← | ← |
| EGAA (self-adhesive) — Roll width | m | 1–6 | ← | ← | ← | — | ← | ← | ← |
They solve different problems. A plastic geogrid goes under the pavement, in the base or subgrade, to spread wheel loads and confine aggregate. A fiberglass geogrid goes inside the pavement, between asphalt layers, to control reflective cracking. Glass fibre is used there because it reaches full strength at ≤ 4% elongation and withstands hot-mix temperatures, neither of which a polymer grid does.
An existing crack or joint moves under traffic and temperature, and that movement concentrates stress at one line in the new overlay. The grid sits in the stress path, takes the load in tension at very low strain and redistributes it across a wider band of asphalt, so the strain at any point stays below the cracking limit. It delays and diffuses the crack rather than preventing movement in the layer below.
The self-adhesive EGAA grid has a pressure-sensitive backing and release film: clean the surface, roll it out, peel and press it down, no nails needed. On small resurfacing jobs a separate tack coat can be omitted, which is the main reason to choose it. On larger or dusty sites, on milled surfaces, and in hot weather, we still recommend a light tack coat under the standard EGA grid with nails or staples — the adhesive alone does not hold well on a loose or dirty surface.
Plan on at least 40 mm of asphalt over the grid. The grid only works when it is fully confined in the mix, and a thin surfacing does not develop enough confinement — it can also be dragged or lifted by the screed. Follow the overlay thickness in your project specification where one is given.
Yes. Glass fibre grids are brittle and break into short filaments under a milling drum rather than winding around it, which is one practical advantage over polymer grids in asphalt. The millings can go back into RAP within the limits your local specification sets for reclaimed material. Very high-strength grades and dense meshes mill more slowly, so tell the crew the grid is there.
For municipal resurfacing and light traffic, 25–50 kN/m is typical. Highways, heavy-truck routes and concrete slab rehabilitation usually call for 80–120 kN/m. Airport aprons and port yards are designed case by case. Where a project specifies geogrid for roads by tensile strength at a given strain, send us the specification and we will match the grade.
Mesh is available at 12.7 × 12.7, 25.4 × 25.4 or 50 × 50 mm, with 25.4 mm the usual choice. Standard roll widths are 2, 4 and 6 m, within a 1–6 m range. Strength, width and mesh can be customised to order. Roll length and mass per unit area are not published for this line and are confirmed per order.
Yes. We knit and coat fiberglass geogrid in-house, alongside the geomembrane and geotextile ranges we produce. Because the grade, mesh size and coating are set on our own lines rather than bought to another mill standard, we build to the specification a project calls for, and every shipment ships with a current mill test certificate.
Tell us quantity, destination port, and any questions — we reply within one business day.
Geogrid Punched and drawn PP biaxial geogrid for subgrade stabilization and base reinforcement — 15-15 to 50-50 kN/m grades, square apertures, 93% junction efficiency.
Geogrid PP and HDPE uniaxial geogrid for retaining walls, MSE walls and reinforced slopes — 60–300 kN/m machine-direction strength, long oval apertures, low creep.
Geogrid Warp-knitted PET geogrid with published long-term design strength — 34 to 452 kN/m LTDS at a 120-year design life, PVC, SBR or bitumen coated.
