What Is Depression In The Pavement? What Causes Depressions on the Road?
What is Depression in the Pavement?
Pavement depression is a term used to describe a small area of the pavement surface slightly lower in elevation than the surrounding pavement. These depressions may not be noticeable until after it rains and water pools in the depression, creating a small “birdbath” area.
These issues can occur due to improper compaction of the underlying soil, water infiltrating the surface and eroding the base material, inadequate drainage, and cross-grade problems.
As the depression deepens and widens over time, it becomes increasingly difficult and costly to repair. Depression in pavements can lead to traffic hazards by causing depressions that can cause motor vehicle accidents if they aren’t repaired properly.
What Causes Depressions on the Road?
Depression in the road results from multiple factors, such as inadequate road design, lack of proper maintenance and construction regulations, surface water drainage issues, vehicle load overloads, and temperature variations.
Poor design can lead to lousy material choices and poor construction practices like overloading vehicles beyond the safe payload capacity or changing pavement temperatures too quickly.
Furthermore, water drainage problems may affect the surface of roads, making them slump and form depressions on their own or in combination with inadequate construction techniques and materials choices.
Lastly, heavy traffic loads can cause structural damage to roads leading to long-term subsidence, which often forms potholes or other surface defects.
What Are The Types Of Pavement Distress?
Twelve types of pavement distress can be identified through manual inspection. These include transverse cracking, rutting, map cracking, potholes, longitudinal cracking, raveling, depression, pumping, bleeding, bumps, poor skid resistance, and roughness.
Transverse cracking runs in the direction opposite to traffic flow and is caused by thermal contraction or aging.
Rutting is a permanent deformation that occurs primarily in asphalt pavements when the bituminous binder dries out due to traffic volume and heavy loading.
Map cracking is an interconnected pattern of cracks in all directions which suggest a map-like appearance.
Potholes are excavations created when repeated compression forces break up pavement layers over time.
Longitudinal cracking follows the center line of the paved surface along a longitudinal direction due to fatigue failure of the asphalt layer.
Raveling is the wearing a way of surface aggregates commonly found on shoulders or curves due to improper compaction and inadequate drainage.
Depression is depressions on the surface caused by the deformation of underlying subgrade layers under traffic loadings or underground water pockets.
Pumping appears as a rising water film behind passing tires from accelerated lane-to-shoulder drainage during wet weather conditions, which disrupts surface friction course material and causes voids below pavement surfaces.
Bleeding signifies wet spots on road surfaces caused by too much asphalt binder in the asphalt mix or aging and oxidation process resulting in asphalt seeping up from underneath the pavement surface onto its upper layer.
Bumps refer to localized vertical displacement with an abrupt elevation change, often due to settlement or plastic deformations in underlying layers.
Poor skid resistance occurs when tire adhesions are low between the road surface and the tire, causing vehicles to hydroplane while braking or turning suddenly.
Lastly, roughness results from wear and tear of pavements leading to bumps that cause discomfort for drivers and passengers while traveling over them.
How Do You Fix Depression In The Pavement?
To fix depression in the pavement, one should first identify the cause of the problem. If it is due to a sinking subgrade or poor drainage, the underlying issue must be addressed before any repair work can begin.
Once the root cause has been identified, the depressed area should be cleaned, patched, and leveled using asphalt-based cold patch material. Potholes should then be filled with hot mix asphalt (HMA) and tamped down firmly for a permanent bond.
Finally, cracks and damaged edges should be sealed using an appropriate sealant to prevent further damage from water infiltration.