Which of the following is NOT a listed tack coat type?

• A. CRS-3
• B. RS-1
• C. MS-1
• D. CSS-1

Answer: (A)

Tack coats are defined by specific asphalt emulsion types that the agency approves for bonding between pavement layers. The types you’d typically see listed for SCDOT tack coats are RS-1, CSS-1, and MS-1, each chosen for a particular setting time and performance to suit the paving schedule. CRS-3, on the other hand, isn’t part of that approved list of tack coat options in these specs, so it isn’t a listed tack coat type. In practice, you’d stick with the emulsion types the contract specifies for bonding between lifts; using an emulsion not on the approved list would require a modification or special approval.