Asphalt preservation, before it becomes replacement

Asphalt does not fail suddenly. It oxidizes, goes brittle, loses its grip on the aggregate, and lets water into the structure. Terra Fog treats aging asphalt and chip seal while there is still something to preserve.

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Where Terra Fog goes in an aged chip seal A section through an aged chip seal: stone chips sit in a layer of aged asphalt binder over the base. Terra Fog, shown in orange, fills the binder between the chips and runs into a small crack, rather than coating the tops of the stones.
  • Stone chips
  • Terra Fog, in the binder between the chips and into small cracks
  • Aged binder
  • Base
Illustration of the mechanism described in the Terra Fog product documentation. Not to scale.

The cost of waiting

Preservation is a maintenance line. Replacement is a capital one. The gap between those budgets is the whole argument for treating a surface before it needs rebuilding.

  • Oxidation makes the binder brittle

    Asphalt hardens with age and exposure. A brittle binder cracks, and cracks are how water gets in.

  • Chip seal starts shedding stone

    When aged binder can no longer hold the chips, aggregate comes loose: a windshield liability as well as a surface failure.

  • Water reaches the base

    Once water is through the surface it works on the layer that carries the load, and surface damage becomes structural.

  • Fines pump out of the base

    Heavy rain on a compromised surface draws fine material up out of the base, hollowing out the layer doing the work.

How Terra Fog works

Terra Fog is a non-petroleum maintenance treatment for aged asphalt and chip seal surfaces. Its low viscosity carries it into the asphalt binder rather than onto the stone, which the documentation gives as the reason it limits the friction loss seen with other fog seals.

It penetrates between the aggregate and seals the surface, slowing the oxidation that makes binder brittle, and reaches into small cracks to protect the base from water.

It contains no solvents and is water soluble. The documentation states that only water evaporates as it cures.

The documentation also reports test sections where the pumping of fine material into the base after heavy rain was substantially reduced.

Source: Terra Fog product data.

Where it applies

Preservation works on pavement that is aging, not pavement that has already failed. If the structure underneath is gone, this is the wrong product and we will say so.

  • Highways

    Aged asphalt wearing surfaces and chip seals on higher volume routes.

  • Streets

    Municipal and county streets on a preservation cycle rather than a rebuild cycle.

  • Parking lots

    Commercial and institutional lots where full resurfacing is not yet justified.

  • Airfields

    Runway, taxiway, and apron surfaces, where loose aggregate carries its own risk.

Application requirements

No special equipment, but the conditions are not negotiable, and one of them affects safety.

  1. Clean the surface thoroughly

    A power broom or blower works best. The product has to reach the pavement, not the dust on it.

  2. Check it is dry and warm enough

    The surface should be dry and above 55°F (13°C), which the documentation also gives as the most suitable temperature for spraying.

  3. Dilute and distribute evenly

    Mixed with water in a holding tank and spread evenly over the asphalt. No special equipment or handling is required.

  4. Do not over-apply

    The documentation states that over-application may reduce skid resistance. Follow the suggested rates: this is the one place where more is worse.

Dilution for Terra Fog only: 1 part product to 3 to 5 parts water. Source: Terra Fog product data. The rate for a specific surface comes out of an assessment of that surface.

  • Prime coats

    Terra Prime is a non-petroleum prime coat developed as an alternative to MC-30. Terra Prime

  • Cold in-place recycling

    Where the asphalt is worn out rather than aging, Top-Seal Black can rebind it in place as the new layer. Top-Seal Black

  • Unpaved roads and bases

    Where the problem is the base, not the surface. Soil stabilization

What we are not claiming

  • We are not repeating the literature's broad safety statements. No safety data sheet for Terra Fog has been supplied to us yet, so ask for it before any application.
  • We do not claim a guaranteed number of years of extra pavement life. That depends on the surface, the traffic, and the climate.
  • It will not rescue a pavement whose structure has already failed. Preservation is for surfaces with life left in them.

Documents

Is your surface worth preserving?

Send the location, area, surface type, its age if you know it, and what it is doing now. If the structure is gone and preservation would be money wasted, that is the answer you will get.

Request a Project Assessment

936-208-9076
info@solidearthsolutions.com

We reply within 24 to 48 hours.