40 Crack Sealing ($) Crack sealing is a pavement maintenance technique that involves the placement of specialized treatment materials into working cracks to prevent water and incompressible particles from entering and deteriorating the pavement structure. Working cracks are defined as those that show significant movement, typically more than 0.1”, due to changes in temperature and pavement movement. Crack width significantly influences the appropriate sealing method. For narrow cracks (less than 1/4”), routing is recommended prior to sealant injection to enhance adhesion and penetration. Cracks between 1/4” and 1” can typically be sealed effectively with typical hot-pour materials, while cracks exceeding 1” often require more substantial repair methods or materials such as hot-pour mastic. Here’s a step-by-step explanation of the crack-sealing process: 1. Crack Preparation: Cracks must be prepared before sealing, which often involves routing to enlarge the crack into a reservoir and cleaning it of debris and moisture. This can be done with brushes, air compressors, hot air lances or other methods. 2. Material Selection: The sealant material used for crack sealing is specifically designed to be elastic and capable of expanding and contracting with the pavement’s movement. Common materials include hot-applied rubberized asphalt sealants, silicone and pre-formed compression sealants. 3. Sealant Application: The selected sealant is then applied into the crack using specialized equipment such as a melter applicator, which heats the sealant to a liquid state before it is poured into the crack. 4. Finishing: After the sealant is applied, it may be tooled or squeegeed to promote good bonding with the crack walls and to create a smooth, level finish with the pavement surface. 5. Curing: The sealant must cool and cure before the pavement is reopened to traffic. The time required for this can vary depending on the sealant type and environmental conditions. The benefits of crack sealing include: • Water Infiltration Prevention: It effectively prevents water from entering the pavement structure, reducing the potential for freeze-thaw damage and sub‑base erosion. • Extended Pavement Life: By maintaining the pavement’s integrity, crack sealing extends its service life. • Cost Savings: It is more cost-effective to seal existing cracks than to repair more extensive damage after water has entered and weakened the pavement. • Maintained Pavement Performance: Crack sealing helps sustain the pavement’s strength and performance by keeping the surface intact. Crack sealing is considered a critical preventive maintenance activity and is typically performed on cracks that are actively widening and shrinking. It is more specialized than crack filling, as it uses materials designed to bond to the crack edges and stretch as the pavement moves, providing a longer-lasting solution.
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