In an independent study, sealing cracks in pavement (crack sealing) has proven to be the lowest cost pavement preservation treatment available by far. In asphalt pavements, the next lowest cost pavement preservation treatment is a single chip seal which is approximately a whopping 4 times more expensive. Simply stated, a dollar spent crack sealing returns more benefit than a dollar spent with other preservation treatments. If your goal is to preserve your pavement for the longest period at the lowest cost you must crack seal.
Approximately 75% of cracks in asphalt pavement form into potholes within 3 years if they are not sealed. In drastic comparison, only approximately 1% of cracks that have been sealed will form into potholes within 3 years.
Cracks are inevitable and are going to develop as the asphalt pavement continues to oxidize and deteriorate. However, crack sealing has been proven in studies to slow the rate of cracking. In one study, after 2 years of observation, 75% less cracking was observed in a pavement that was crack sealed in comparison to a pavement that received no treatment at all. Crack sealing can slow the rate of their formation in pavements over time.
Crack sealing as a pretreatment improves the effectiveness of other surface treatments in asphalt pavements. For example, a study showed that when crack sealing was completed as a pre-treatment to a chip seal, 100% less cracking developed after 2 years of observation in comparison to a chip seal only treatment. The chip seal only treatment had already deteriorated back to be equivalent to the “control” pavement that had no treatment completed at all.
In another example, crack sealing plus microsurfacing resulted in 60% less cracking vs. no treatment at year two. Microsurfacing alone resulted in only 15% less cracking vs. no treatment at year two. Again, crack sealing as a pretreatment improves other surface treatments.
If you want to get the most service life from your pavement, crack seal early and often!
- Pavement cracking is inevitable – it is going to happen
- Sealing cracks quickly after they develop reduces the damage to the pavement
- The longer the cracks remains sealed, the longer the pavement will perform
- Visually inspect pavements every year to identify and seal new cracks. Cracks greater than 1/8” (3 mm) must be sealed to achieve the best protection of the pavement.
- Visually inspect previously sealed cracks every year to identify failures and repair as needed. If annual inspection is not possible, previously sealed cracks should be assessed every 3 years, the time it potentially takes for a crack to turn into a pothole.
What is the difference between Crack Sealing & Crack Filling?
For simplicity, crack sealing is generally installing crack sealant (specialized material) which may or may not include a reservoir. Crack filling is generally installing crack filler (non-specialized material).
However, when it comes to conducting and following the research, a better definition is needed. To answer the question, we start with a definition of terms. It is very important to understand these terms, so we fully understand what research has proven and how to apply the research results to maximize your investment and achieve your pavement’s goals. Crack sealing and crack filling are often used interchangeably, but they are not interchangeable.
The four terms are:
- Crack sealant (material)
- Crack filler (material)
- Crack sealing (process)
- Crack filling (process)
- Is specialized material that bond to the walls of the crack and can move horizontally and vertically with the pavement as it expands and contracts;
- Prevents intrusion of water and debris into the crack;
- Is specifically engineered to remain flexible at low temperatures so it does not crack or split open and remains stable at higher temperatures so that it does not track or bleed on the pavement.
Examples of crack sealant are Crafco Roadsaver, Polyflex and Asphalt Rubber hot-applied sealants.
- Is ordinary material that may bond to the walls of the crack but cannot move horizontally and vertically with the pavement as it expands and contracts;
- Reduces intrusion of water and debris into the crack;
- Is not specifically engineered to remain flexible at low temperatures and may not remain stable at higher temperatures.
When pavement movement takes place due to temperature change or traffic loads, the crack filler is separated from the edge allowing water and incompressible materials to enter the crack and into the pavement. Examples of crack filler are asphalt cements, liquid asphalt, cutback asphalts, or asphalt emulsions that may be mixed with sand, which occasionally is referred to as ‘oil and sand’.
As you can see from the definitions, there are differences in the materials that are designed for different purposes – prevention vs reduction of infiltration is a significant difference. The process of installing these materials can also differ and have different outcomes.
Crack sealant can be installed into a reservoir and is often referred to as a crack sealing installation. When crack sealant (specialized material) is installed into a reservoir it can have a variety of finishing techniques, and to name a few: (a) standard recessed band-aid, (b) shallow recessed band-aid, and (c) standard reservoir and flush. Crack sealant can also be installed without a reservoir and is often referred to as a ‘blow and go’ also known as ‘crack filling’ installation where the finishing technique is (a) capped or overband, or (b) simple flush fill.
Crack filling as a process is thought of as a ‘blow and go’ application of crack sealant, as noted above. However, keep in mind that crack filler consists of different materials than crack sealant and is not placed in a reservoir with the same intent and purpose (prevention vs reduction of infiltration), and therefore you would not use a crack sealing installation using a reservoir for crack filler products.
So, for a simple conclusion, crack sealing is generally installing crack sealant (specialized material) which may or may not include a reservoir. Crack filling is generally installing crack filler (non-specialized material). Crack sealant has been proven in independent studies to perform in asphalt pavement from 2 to over 10 years depending on pavement condition of poor to good, respectively. Crack sealant has proven to perform in concrete up to 21 years. Crack filler has proven generally to perform from 1 to 2 years. Crack sealing is a long-term pavement preservation solution while crack filling is a band-aid. Pavement is always moving horizontally or vertically to some degree and therefore sealing is preferred over filling so that you can truly preserve the gigantic investment in our roads.
What type of solution do you need for your crack sealing project?
There are a variety of crack sealing solutions, and categorizing them can be challenging. Generally there is hot-applied asphaltic-based crack sealant and cold-applied crack sealant. Cold-applied crack sealant should not be confused with cold-applied silicone joint sealant because cracks and joints are different as noted above.
Crafco focuses on quality and long-term performance and therefore manufactures products that have a significant service life like hot-applied asphaltic-based crack sealant and cold-applied silicone joint sealant that have demonstrated in independent studies to provide the longest service life available.