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What is open graded pavement?

What is open graded pavement?

Open graded friction courses (OGFCs) are a type of pavement that have been built across the United States since the 1950’s. These asphalt mixes contain only a small portion of fine aggregate, creating a pavement with a relatively large percentage of air voids.

What is the meaning of open graded aggregate?

An aggregate containing little or no mineral filler, or in which the void spaces in the compacted aggregate are relatively large.

What is Open Graded tarmac?

Open-Graded Tarmac There are times when tarmac driveways are comprised of what is known as an open-graded aggregate. This essentially signifies that there are relatively few smaller particles within the mixture. Thus, open-graded driveways tend to be somewhat permeable.

What does open graded stone mean?

What is an Open-Graded Base? An open-graded base is one that allows water to permeate through it with little resistance. The lack of fines in the open-graded aggregate does not allow for it to hold on to the water. Instead, the water permeates through the base material.

When was open graded friction course ( OGFC ) created?

Open-graded friction courses (OGFC) have been used across the U.S. since the 1950’s to improve the surface frictional resistance of asphalt pavements. In 1974, the Federal Highway Administration (FHWA) developed an OGFC mix design procedure to be used by state departments of transportation (DOTs).

What kind of pavement is an open graded friction course?

Open graded friction courses (OGFCs) are a type of pavement that have been built across the United States since the 1950’s. These mixes contain only a small portion of fine , creating a pavement with a relatively large percentage of air voids.

What should you avoid when using open graded friction courses?

Concerns. The aggregate structure of open graded friction courses makes them particularly susceptible from raveling. To avoid accelerated raveling, their use should be avoided in areas where snow and ice occur. Chains, studded tires, and snowplows are all known to aggravate raveling in OGFCs.

What is a high friction surface treatment ( hfst )?

High friction surface treatment (HFST) is a safety- first pavement treatment intended to restore and maintain pavement friction to reduce crashes. is a It thin layer of high-quality polish-resistant aggregate bonded to the pavement surface with polymer resin binder, specified in FDOT Section 333. FIGURE 1 – High friction surface treatment.