Crack Sealing as Pretreatment: Does It Work?
It’s just an unfortunate, unavoidable fact of life: asphalt is going to crack. At least initially, these cracks are simply a surface defect — largely an aesthetic problem. However, when left untreated, cracks can seriously affect the structural integrity of the asphalt. Because of this crack sealing is incredibly important maintenance. In fact, according to the Asphalt Institute, crack sealing is the single most important pavement activity in order to prevent this more serious structural damage. Furthermore, a recent study from the National Center of Asphalt Technology (NCAT) indicates that crack sealing as a pretreatment improves the efficacy of other prevention treatments, such as pavement overlays. In this blog post we examine crack sealing, its importance and the significance of this study’s findings.
What is Crack Sealing?
Crack sealing is the placement of specialized treatment materials (either a hot or cold sealant) into cracks to prevent water intrusion and other deteriorating forces. Typically, a cold pour is used for smaller cracks up to ½ inch wide. A hot pour is a longer lasting product that is used for larger cracks up to 1 ½ inch wide.
How Do You Crack Seal Asphalt?
Crack sealing should only be performed on structurally sound pavement. If asphalt has base failures, significant rutting or alligator cracking, crack sealing will not be an effective reparative measure. Crack sealing is an important maintenance procedure to prevent those larger structural issues from occurring. Sealing should be performed on dry pavement when the temperature is above 40ºF but not too warm. Extreme temperatures cause the cracks to dramatically expand and contract. If a detackifying agent is used, traffic on the pavement can resume immediately. If not, traffic should not be allowed until the sealant has cured.
Why Does it Matter?
As stated above, crack sealing is an incredibly important asphalt maintenance measure. Sealing cracks in a timely manner prevents water penetration. Water penetration accelerates deterioration in asphalt as it exacerbates the contraction and expansion that occurs with changing temperatures. Water can worsen cracking and cause potholes. If the water reaches the base of the asphalt, it can lead to base failures and serious structural damage. Crack sealing helps to prevent this extreme and costly deterioration. Crack sealing can provide a 10-point increase in the Pavement Condition Index and sustain that increase for 7 years. In fact, the procedure can maintain pavement smoothness for 5 years and can extend the life of the pavement by up to 5 years.
Crack Sealing as a Pretreatment
As the recent NCAT study indicates, crack sealing is not only effective as a maintenance procedure but also as a pretreatment for other prevention treatments. Crack sealing the pavement before applying other treatments significantly improves the efficacy of those treatments and further extends the life of the pavement. The study took place from 2012-2015 and found that:
- Crack sealing reduced the development of interconnected cracking and reduced subgrade moisture levels.
- Crack sealing as a pretreatment improved the treatment results of chip seals and microsurfacing.
More specifically, the study found that, after two years, the pavement that had been crack sealed as a pretreatment to chip sealing had 125% less cracking than the pavement that had only been chip sealed. Similarly, after two years, the pretreated pavement exhibited 45% less cracking than the pavement that had only been microsurfaced.
This study demonstrates the enormous benefits of crack sealing both as regular maintenance and as a pretreatment for other prevention treatments. Crack sealing is one of the lowest cost treatments, giving it the highest benefit to cost ratio. Therefore, crack sealing is one of the best investments to make in the life of asphalt pavement. Contact DC Construction today to crack seal your asphalt and extend the life of your pavement.