AASHTO M 349-22

This standard specifies quality requirements for emulsified asphalt or performance-graded asphalt binder for tack coats.

A tack coat is the application of an emulsified asphalt or performance-graded (PG) asphalt binder, to an existing pavement surface just prior to placement of a pavement overlay course. The tack coat is used to ensure a good bond between an existing asphalt or concrete pavement and a pavement overlay course, between multiple pavement lifts of a structural pavement, and at any vertical surfaces to which a new pavement layer will be placed adjacent, such as curbs, gutters, utilities, and construction joints.

This standard was formerly designated as provisional standard MP 36.