MarMac C 990

C 990 compliant butyl mastic sealant


Looking for a Premium Grade Black Butyl Based Sealant?

MarMac C 990 is a flexible preformed, premium grade black butyl based rope sealant designed to be (when used on precast concrete):

  • Permanently flexible
  • Tacky
  • Resistant to moisture
  • Resistant to deterioration due to exposure of dilute chemical solutions

MarMac C 990 self-seals joints in:

  • Manholes
  • Septic Tanks
  • Box Culverts
  • Concrete Pipe
  • Concrete Valves
  • Utility Valves
  • Vertical Panel Structures

MarMac C 990 meets the requirements of ASTM C 990 Section 6.2 and AASHTO M-198 (with the exception of flash point and fire point). It is easily applied, can be installed faster, permanently flexible creating a hydrostatic performance, and has no shrinkage. MarMac C 990 is also non corrosive and will not oxidize or harden with age. MarMac C 990 is also able to be applied under extreme outdoor weather conditions with no adhesion loss or cracking. It is supplied in roll form on an easy release liner with standard sizes of .75″, 1″, and 1.25″.

Tell us about your application and let our experts help find the best solution for your situation—and send you a free quote!

Also ask about MarMac C 877 Type III.




Meets or Exceeds Industry SpecificationsAASHTO M-198*

ASTM C 990 Section 6.2

Chemical Resistance:

30 day immersion testing

No visual deterioration
Cold weather flexibilityNo adhesion loss

No cracking

Wide Application Temperature RangeAble to apply under extreme outdoor weather conditions
• Easy application

• Permanently flexible

• No shrinkage, non corrosive, will not oxidize or harden with aging

• Faster installation

• Hydrostatic performance

• ASTM C 990 Sec. 10.1 psi for 10 min


Application Properties


Typical Value

Service Temperature Range

-40°C to 121°C (-40°F to 250°F)

Application Temperature

-7°C to 49°C (20°F to 120°F)


Below 49°C (120°F)

Shelf Life

2 years


NOTE: The foregoing information is published as general information only. The listed properties and performance characteristics are approximate values and are not to be interpreted as manufacturing specifications.