Explore the causes behind five different kinds of asphalt pavement distress.
Asphalt pavement is an amazing material that can last for decades, but that’s if it’s properly installed and maintained. Asphalt will show signs of pavement distress when it’s either installed incorrectly or in need of maintenance. Explore the causes behind five types of pavement distress below.
Five Asphalt Pavement Distresses and their Causes
Knowing what is behind the signs of asphalt pavement distress is important in order to fix the problem correctly. Patching over cracks or filling potholes is a temporary solution at best if the underlying cause is not fixed. These are the five most common forms of asphalt pavement distress and their causes.
- Cracks. There are many different types of cracks that can form in asphalt, and they have different causes. Fatigue cracking, or alligator cracking, is caused by overloading, the pavement isn’t thick enough, a weakened base course or subgrade, or a combination. Block cracking’s rectangular cracks are caused by shrinkage of the asphalt pavement when temperatures fluctuate greatly. Edge cracks form due to lack of support at the edge of the pavement.
- Distortion. Distortion is the changing of the asphalt’s shape, usually due to weakness of the base and/or subgrade layers or an unstable asphalt mix. Rutting, or shallow depressions usually caused by vehicle tires, is due to insufficient pavement thickness, lack of compaction, and weak asphalt mixtures. Shoving, or where the asphalt has formed ripples, is usually caused in response to repeated stressors like vehicles stopping in an intersection; the asphalt is either too soft, has a weak granular base, has a fine or rounded aggregate, or there is too much asphalt.
- Disintegration. This is where asphalt pavement deteriorates into smaller particles that are carried away. Potholes are generally caused by the lack of maintenance when some other form of distress has occurred, such as cracking. Raveling is when the aggregate particles are worn away, and it’s usually caused by hardened asphalt or the asphalt mixture was poor.
- Skidding hazards. These hazards include water pooling on a roadway, the polishing of aggregates due to traffic, and bleeding. Bleeding is when the pavement’s surface is mainly asphalt (and not a mixture of asphalt and aggregates) and is caused by an unstable asphalt mix, too much asphalt in the mix, an excess amount of a tack or bond coat, or through poorly constructing a seal coat.
- Surface Treatment Distress. The surface treatment of an asphalt pavement can also become distressed. The loss of a cover aggregate can be caused by dirty aggregate, using too little asphalt in the mix, poor construction processes, or allowing traffic to use the pavement before it has seated and bonded. Additionally, streaking, or different bands of aggregate or asphalt present in the pavement, is caused by an uneven application of an asphalt mixture.
Tucker Paving has over 25 years of experience in the asphalt and concrete paving industry, and our commitment to doing a job right the first time has never waivered. Contact us for assistance with your next concrete or asphalt installation, maintenance, or repair project.