What Is Reflection Cracking In Pavement?
What Is Reflection Cracking In Pavement?
Reflection cracking in pavement is a type of cracking that occurs when an existing surface layer or asphalt overlay on the pavement fails.
It is caused when the layer below has weakened, due to either poor construction practices or inadequate substructure support.
Because of this failure, stress concentrations develop in the pavement and are transferred up through the surface layer, resulting in large-scale cracks within the pavement.
Reflection cracking can lead to further weakening of the surface layers and significant deterioration of pavements over time if left untreated.
How Does Reflective Cracking Occur?
Reflective cracking occurs when an underlying pavement layer is subject to stress, causing it to crack, which then reflects the cracks up through any layers of asphalt that are applied on top of it.
This can occur for a variety of reasons, including subsurface movements due to traffic or climate-induced volume changes, structural failure of the underlying layer, poor construction practices during construction that lead to weak points in the pavement cross-section structure, and inadequate maintenance such as sealing cracks in the lower layers.
As these underlying layers move and fail, they create excessive compressive stresses in adjacent asphalt layers which manifest as reflective cracks along existing joints and cracks in the upper layers.
How Do I Fix My Reflection Cracking?
In order to fix reflection cracking, the first step is to identify the cause of the issue. Possible causes include improper installation, insufficient troweling or a weak substrate.
Once identified, repair work must be done accordingly – for instance, if it was caused by improper installation then the slab should be taken out and reinstalled according to manufacturer recommendations; if it was due to insufficient troweling then more should be applied before curing; and if it was because of a weak subfloor then strengthening systems may need to be installed.
After fixing the source of the problem, any existing cracks should then be filled with an approved patching compound and sealed properly.
Finally, applying a sealer over the entire surface will help keep further damage from occurring.
What Is Reflective Cracking Membrane?
A reflective cracking membrane (RCM) is a type of waterproofing membrane used to protect against water and air infiltration.
It consists of an asphalt-modified polymer film with a rubberized asphalt adhesive that helps seal out moisture and promote a longer lasting bond.
Reflective cracking membranes are typically installed as a top coat over existing asphalt or concrete surfaces, providing protection from UV radiation, temperature fluctuations and weathering.
They provide superior resistance to pavement distortion, thermal expansion, reflective cracking, and oxidation caused by rain.
The use of this product helps maximize the lifespan of roads, driveways and parking lots while reducing necessary maintenance costs over time.
What Causes Reflective Cracking?
Reflective cracking is a pavement distress caused by underlying asphalt layers cracking in response to movement of the pavement surface above.
It occurs when an existing layer of asphalt cracks and then through traffic loading, these cracks are reflected to the top layer.
It is usually caused due to poor construction practices such as failing to properly bond or construct tie-in joints between different pavement layers, inadequate compaction levels leading to decreased load carrying capacity of the underlying asphalt layer, using inferior quality materials, or using too little asphalt binder in the mix.
How Do I Prevent Reflective Cracking?
Preventing reflective cracking is a multi-faceted approach. The first step is to create a strong and durable base or subbase that can withstand the load of the pavement and its environment.
This includes using high quality aggregates, modified pavement materials, geogrids, and reinforcing fabrics.
Additionally, cracks should be sealed promptly with hot pour sealants or cold pour sealants to prevent water from entering the underlying layers.
Crack routing can also help to stress relief by increasing the width of cracks as well as reducing their depth before filling them with sealants.
Finally, for heavily trafficked roads it may be necessary to incorporate joint seals or specially designed overlays that reduce pressure on the surface layer and divert loads away from areas prone to reflective cracking.
