What is the recommended gap for tack extension beyond the paving width to achieve proper overlap?

• A. 1.5 to 2 inches overlap
• B. 1 inch to 1.5 inches overlap
• C. No overlap
• D. 2.5 inches

Answer: (B)

The gap tested is the amount tack extends beyond the edge of the paving width to create a proper bond at the joint. About one to one and a half inches of tack extension beyond the paving width provides enough overlap so the next lane or pass will bond smoothly to the tack-coated surface, forming a continuous adhesive layer at the joint. If the extension is too large, excess tack can smear or track onto unintended surfaces and cause problems with rollers or surface finish. If there’s no overlap or too little extension, the joint may not bond well, increasing the risk of delamination, raveling, or water infiltration. A 2.5-inch extension is excessive and not necessary to achieve a good bond.