Arizona ADOT Geotextile Fabrics

Solmax DOT Standard Specification Product Chart (click image to expand)

Arizona ADOT - Geotextile Uses

Arizona highways cross hot deserts, caliche-rich subgrades, and streambeds that are bone-dry most of the year but carry intense flows during monsoon storms. Geotextiles help manage that mix. The first role is separation and stabilization. On new pavements and widenings, a woven geotextile is often placed between weak, dusty native soils and imported base. It prevents fines from pumping into the aggregate under traffic, spreads load, and preserves base thickness—especially helpful where construction must proceed over marginal subgrade after grading and dust control waterings.

Water management comes next. Even in arid regions, filtration and drainage are critical. Nonwoven geotextiles line underdrain trenches, wrap perforated pipes, and separate backfill from drainage stone behind retaining structures. In sandy or silty soils common to washes and alluvial fans, matching apparent opening size (AOS) and permittivity keeps fines in place while allowing rapid flow, reducing clogging and soft spots along the shoulder or at the toe of embankments.

Where flows concentrate—washes, culverts, outfalls, and channel linings—geotextiles serve as riprap underlayment. A robust nonwoven filter goes on the prepared slope before armor rock. It prevents subgrade from piping through rock voids during flash floods and helps the riprap “lock in.” This same underlayment protects embankments at bridge abutments and along drainage channels where high velocities and sediment-laden flows are routine in monsoon season.

ADOT corridors include long stretches of retaining walls and grade separations. In these MSE walls and structural interfaces, geotextiles act as joint and face filters—placed behind panel or block joints so backfill fines don’t migrate to the face. The fabric maintains drainage continuity while keeping the wall’s appearance clean and preventing loss of material into the fascia.

Arizona also makes heavy use of pavement interlayers. Asphalt-impregnated nonwoven geotextile beneath overlays reduces water intrusion and slows reflective cracking—important where daily thermal swings and oxidizing heat age pavements quickly. On chip seals, geosynthetic interlayers can improve waterproofing and extend service life, particularly on high-volume urban freeways.

For temporary erosion and sediment control, geotextiles show up in silt fence, inlet protection, and check structures. Even small rainfall events can move fine dust; fabrics let water bleed through while trapping sediment so re-vegetation or permanent armoring can take hold. At project entrances, stabilized construction exits typically include a nonwoven geotextile under coarse rock, distributing wheel loads and limiting track-out onto public roads—key for dust compliance in urban counties.

Finally, geotextiles provide liner protection in detention basins, lined ditches, and containment areas. Heavy nonwoven fabrics cushion geomembranes from angular aggregate and construction traffic, cutting puncture risk and extending system life.

Field practice ties it together: prepare subgrades smooth, avoid wrinkles, overlap seams generously, secure with pins or initial lifts, and cover promptly to limit UV exposure in extreme heat. Selection is function-driven—woven for stabilization and tensile strength; nonwoven for filtration, drainage, and protection—tuned to the project’s soils, hydraulics, and traffic.

Bottom line: on ADOT projects, geotextile isn’t “landscape fabric.” It’s a purpose-chosen engineering layer that stabilizes desert subgrades, controls water and fines during monsoon events, protects structures and liners, and stretches pavement life across Arizona’s demanding climate.

Arizona ADOT