Best Practices for Crack Treatments for Asphalt Pavements (2014)

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1 S U M M A R Y Treating cracks in asphalt pavements is a major part of every maintenance engineer’s work. The objective of any crack treatment is to minimize the intrusion of water into under- lying layers of the pavement structure. Such water infiltrates the base layers of the pavement and may lead to pavement structural failures. Crack treatments fall into two broad categories—crack sealing and crack filling. Crack sealing is generally performed on “working” cracks, e.g., cracks that are more than 1⁄8″ in the summer and significantly larger in the winter. However, crack sealing can be used for any crack treat- ment operation. Crack filling is generally performed on cracks that do not open and close due to environmental conditions. Much research has been performed in the United States and abroad on the materials and designs for crack treatments for flexible pavements; however, little is known about variabil- ity in the current state-of-the-practice regarding construction techniques and the resulting effectiveness of crack sealing and crack filling. This report summarizes the state-of-the-art and current state-of-the-practice of crack treatments and concludes with current best practices. This report is limited to crack sealing and crack filling of asphalt pavements, and does not consider joint filling on concrete pave- ments, reflective cracking retardation techniques, joint construction techniques, or other related issues. As would be expected, the state-of-the-art and the state-of-the-practice do not directly correlate to one another. Based on the results of this project, areas in which improvements in the state-of-the-practice should be considered include: • Evaluation of pavement condition prior to sealant application—i.e., what type of crack is present, how severe is the cracking, and what is the density of the cracking; • Acceptance of the new Sealant Grade evaluation system; • Proper preparation of the crack prior to sealant application—making sure that the crack is clean, dry, and properly configured for the application; • Training for sealant application personnel—this is an ongoing need; • Quality Control testing for sealant products—establishment of uniform sampling and testing protocols; • Inspection of the crack treatment operations—many agencies do little if any inspection of crack treatment work; and • Evaluation of sealant performance—understanding how the sealant performs enables owners to make knowledgeable decisions about materials and procedures. Best Practices for Crack Treatments for Asphalt Pavements