What Is Ravelling in Asphalt Pavements?

What Is Ravelling in Asphalt Pavements?

The deterioration of pavement due to the loss of asphalt and rocks is known as raveling. This can be seen by the presence of rocks and sand on the surface and in gutters of the pavement. Over time, the thickness of the pavement decreases until it has completely eroded away.

What Causes Asphalt Ravelling?

Ravelling occurs when a pavement surface begins to deteriorate, often as a result of insufficient or improper maintenance. It is caused by the following:

1. Dust Coating

Dust coating is a form of raveling that happens when dust particles adhere to asphalt pavement.

This form of raveling can be caused by traffic, wind, and the accumulation of sand and dirt on the surface of the pavement.

It generally appears thin at first but can eventually become so thick that it requires treatment with a sealcoat or more extensive asphalt repairs if left untreated.

To prevent dust coating, it’s best to regularly sweep streets and parking lots to remove any accumulated particles from the surface.

Additionally, applying an emulsion sealcoat can help protect against erosion due to external forces like wind and traffic.

2. Aggregate Segregation

Aggregate segregation is one of the main causes of potholes and other road damage. This occurs when two different types or sizes of aggregate combine to form a weak bond between particles, compromising the structural integrity of the road surface.

The smaller aggregate particles are pushed aside by larger ones and can cause spaces that fill with moisture, leading to deterioration and erosion.

Aggregate segregation needs to be addressed in order for roads to remain in safe and serviceable condition, so it is important for municipalities to ensure they are using materials that are properly graded and combined correctly.

3. Traffic Dislodging

Traffic dislodging is one of the main causes of raveling. It occurs when vehicles are unable to move freely due to overcrowded roads or a large number of vehicles moving at the same time.

Traffic jams, congested highways, stop-and-go traffic patterns and bottlenecks can all lead to traffic dislodging, resulting in lengthy delays and extensive travel times.

It is one of the leading causes of frustration for drivers who have to spend extended periods of time stuck in highway traffic or trying to find alternate routes just to get around the jam.

As such, it is important to take steps ahead of time such as preparing an alternate route or taking public transportation when possible in order to reduce travel time and avoid traffic jams.

How Do You Prevent Ravelling?

To prevent raveling in construction, it is essential to use a binding agent such as gravel, crushed stone, asphalt or Portland cement concrete when constructing roads and foundations.

It is also important to ensure the road base material has a minimum thickness of 75mm with proper compaction; this ensures the road is dense and resilient enough to resist raveling.

Additionally, using good quality aggregates for surface course layers can help reduce the chance of raveling, along with ensuring that all potholes are filled in and repaired immediately and that rutting potential is managed through regular pavement assessments.

Finally, it is vital to keep roads free of debris, cracks or other irregularities which can weaken the structure of the road.