The benefits of open-graded friction course

First, let’s define what open-graded friction course is. An “open-graded friction course” is defined as a thin, permeable layer of asphalt that integrates a skeleton of uniform aggregate size with a minimum of fines (Taylor, 2014). They are designed to eliminate skidding on road pavements by providing a rough surface texture, non-polishing aggregate, rapid drainage of surface water, or a combination of all three properties.

Potential applications

There are four reasons why open-graded friction courses would be a good choice of ingredient for your pavements.

Benefits

Advantages of using open graded friction courses include:

·         Reducing noise, often providing a 3 to 5 decibel reduction in tire noise

·         Boosting pavement life and lowering long term costs

·         Facilitating and maintaining good high speed and friction qualities

·         Decreasing potential hydroplaning

·         Reducing splash and spray

·         Enhancing the visibility of painted pavement markings+

Limitations

When compared to other high type roadway surfaces, OGFCs have their limitations, including:

·         The potential for ravelling and shoving

·         An increased potential for stripping

·         The need for special snow and ice control methods

·         The need for special patching and rehabilitation techniques

·         Not adding structural value to the pavement

Open-graded friction courses usually contain higher asphalt content than a dense graded mix, and use asphalt of an equal or harder grade. Heavy asphalt film on the aggregate is essential for longevity as it resists stripping and oxidation of the asphalt cement. No reduction in asphalt content are to be made based on the OGFC’s appearance.

The open-grade course should be tested for its moisture susceptibility due to the high content of air voids which increases the potential for stripping. The mix should also be tested for coating and strength retention, and it should be revised if stripping occurs.

Conclusion

1) OGFCs will continue to be a fantastic ingredient of pavements due to their specific utility, so long as longevity issues are managed with intelligent design and installed with the proper methods.

2) Open-graded mixes contribute positively to roadway safety and the surrounding environment.

References

https://pavementinteractive.org/open-graded-friction-courses-keeping-an-open-mind/

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