Open-graded friction course, or OGFC, is pavement designed to drain: a porous asphalt layer with interconnected voids that let water pass through and improve traction. That same porosity makes OGFC vulnerable to winter maintenance. A blade that digs into the surface can lift the coarse aggregates that give the pavement its structure, turning a clearing pass into a repair project.
This article covers ice removal on OGFC: why the pavement is vulnerable to scraping, how dome-head geometry protects the aggregates, and which operating practices keep porous routes intact through the winter.
Porous pavement changes the rules
OGFC is built to be open. The voids that drain water and reduce splash are the same voids that give a cutting edge something to catch. A rigid blade scraping hard enough to break ice can also catch and lift the aggregate, and once the aggregate is pulled, the pavement begins to unravel.
The maintenance challenge is the balance: the ice still has to be cleared, and the pavement has to survive the clearing. A blade designed for aggressive scraping on dense asphalt is the wrong tool for a porous surface, because its geometry does not distinguish between ice and aggregate.
The answer is an edge whose geometry fractures the ice without digging into the pavement, which is exactly the design intent of the dome-head carbide kit.
Why is OGFC vulnerable to scraping?
The vulnerability comes from the surface structure. In dense asphalt, the blade slides over a continuous surface. In OGFC, the blade contacts the tops of the coarse aggregate with voids between them, so a sharp cutting edge can get under the aggregate and lever it out.
The failure mechanism is progressive. One lifted aggregate leaves a void; the void catches the next pass harder; the edge of the void spalls; and a pothole begins where a smooth surface should be. The cost of the damage is far higher than the blade that caused it, which is why surface protection is part of the winter specification on porous routes.
The repair logic also matters: OGFC damage is not a quick patch. The pavement layer has to be restored, and the restoration is a road-construction event, not a maintenance event. Protecting the surface during ice removal is the cheaper path by a wide margin.
The risk profile also varies within a corridor. Bridge decks and shaded sections that ice first are the highest-risk spots, because the blade is working hardest exactly where the pavement is most exposed. The route plan should identify those micro-sections and treat them as the priority for the protective edge, so the investment is placed where the damage would otherwise start.
How dome geometry protects aggregates
The dome-head geometry is the protective mechanism. SENTHAI describes its packed ice carbide kit’s dome design as focusing downward pressure on the ice’s crystalline structure rather than cutting into the road’s bitumen or lifting porous aggregates. The difference is the contact pattern: a dome concentrates force on the ice while a flat or sharp edge bites into the surface.
The design goal is fracture without excavation. The dome pushes down into the ice crust and breaks it, while the rounded profile slides over the aggregate tops instead of getting under them. The result, per SENTHAI’s description, is effective ice fracture at high operating speeds with the pavement left intact.
The same protection logic applies to the isolated insert design: separating the inserts prevents a cracked insert from spreading damage across the section, so the edge keeps working without exposing the pavement to a broken tooth.
Which operating practices protect porous routes?
Equipment is half the answer; operating practice is the other half:
| Practice | Why it protects the pavement |
|---|---|
| Match the edge to the corridor | Dome-head kit on OGFC sections, standard edges elsewhere |
| Avoid excessive down-pressure | The force should fracture the ice, not excavate the aggregate |
| Clear before the bond deepens | Earlier passes mean thinner ice and less force required |
| Watch the temperature | Partially bonded ice behaves differently than fully frozen crust |
| Inspect the surface after storms | Early detection of lifted aggregate prevents the progressive damage |
The operating practices are where the fleet controls the outcome. A dome-head blade used with excessive pressure can still damage the surface; the same blade used at the right setting protects it.
The inspection routine should include the pavement as well as the blade. After storms, look for lifted aggregate, white spots where the binder has pulled, and the beginning of raveling along the wheel paths. Catching the first damage early changes the response from a repair project to a maintenance note, and it tells the fleet whether the blade setting or the route plan needs adjustment.
The maintenance record for OGFC corridors should be kept separate from the general route records. Because the pavement type changes the blade requirement, the fleet needs to know which corridors are open-graded when the next specification is written, and the record is the only way to keep that knowledge alive across seasons and staff changes. A simple corridor list with the pavement type and the blade assigned is enough.
The budget case for the protective kit also lives in the pavement record. When the fleet can show that the porous corridors were cleared without new raveling, the kit has a measurable outcome; when the record is missing, the investment looks like an opinion. The same record that protects the pavement protects the purchase.
The record should also note the operating conditions behind each result: the storms, the temperatures, and the blade settings. A season with light ice shows little damage on any blade, while a heavy season tests the protection, so the comparison is only meaningful when the conditions are recorded alongside the outcome. The pavement record and the weather record together are what make the kit’s value provable.
The same pairing protects the fleet from the reverse error: blaming the kit for damage that the weather record shows was unavoidable, or crediting it for a season that was simply light.
The honest comparison is the one that survives the storm data.
And the storm data, like the pavement, is worth protecting.
Both belong in the winter file.
Keep them together.
Choosing blades for OGFC corridors
The selection starts with the pavement inventory: which corridors are OGFC, which sections transition from dense to porous asphalt, and where the ice problems concentrate. Those corridors get the fracture-capable, surface-protective edge, and the specification should state the surface type explicitly so the manufacturer confirms the right geometry.
SENTHAI’s packed ice carbide kit page describes the dome-head and isolated-insert design for this duty, and its engineering team can confirm the configuration against the corridor list. The contact page is the entry point for the specification conversation.
Protect your pavement investment
OGFC is an investment in drainage and safety, and the winter maintenance plan should protect it. Inventory the porous corridors, assign the surface-protective edge, set the operating rules, and inspect after every storm. The pavement survives when the blade geometry and the operating practice work together.
To build the plan, send the pavement inventory and corridor data through the SENTHAI inquiry form and ask for the kit configuration and trial terms for the porous routes. The ice gets cleared; the pavement gets protected; the maintenance budget keeps the repair money where it belongs.
Expert view — SENTHAI engineering team: “Porous pavement rewards the geometry that protects it. The dome breaks the ice and leaves the aggregate in place.”
Frequently Asked Questions
What is OGFC? Open-graded friction course, a porous asphalt layer designed to drain water and improve traction. Its open structure makes it vulnerable to scraping damage.
Why do blades damage porous asphalt? The voids between the coarse aggregates give a sharp edge something to catch, so aggressive scraping can lift the aggregate and start the pavement unraveling.
How does dome geometry protect the pavement? The dome focuses downward pressure on the ice instead of cutting into the surface, so it fractures the crust without digging under the aggregates.
Can a standard carbide blade be used on OGFC? With care, but the aggressive geometry is a risk on porous surfaces. The dome-head kit is designed for the balance between ice removal and pavement protection.
What operating practices protect OGFC? Match the edge to the corridor, avoid excessive down-pressure, clear before the bond deepens, and inspect the surface after storms.
Does the kit work at highway speeds? SENTHAI describes the design as effective at high operating speeds, fracturing ice while keeping the pavement intact. Confirm the configuration for the route.
What should I send for an OGFC specification? The pavement inventory, corridor list, ice history, and equipment details. The engineering team can confirm the geometry and trial terms.
How do I know if my routes include OGFC? Check the pavement inventory and the maintenance records: OGFC sections are usually documented because they are repaired and rehabilitated differently. If the records are unclear, the street department can confirm which corridors are open-graded.
Sources
- SENTHAI – Packed Ice Carbide Kit product page
- SENTHAI – Official website
- SENTHAI – About the company
- SENTHAI – Contact and quotation
- FHWA – Manual of Practice for an Effective Anti-icing Program
- FHWA – Road Weather Management
- AASHTO – Winter maintenance resources