SpecChem > Products > Polyureas > Rapid Flex CJ

Rapid Flex CJ

Rapid curing, semi-rigid polyurea control joint filler

Rapid Flex CJ is a top-grade, 100% solids, two-component, UV-resistant, semi-rigid, rapid-curing polyurea solution designed for filling control and construction joints in industrial concrete floors. Its formulation allows for quick shaving of joints, facilitating fast project turnaround. Developed to meet the ACI 302, section 4.10 recommendations for joint fillers, Rapid Flex CJ features a Shore A Durometer of 85. It’s also effective for repairing damaged joint nosing and cracks, with additional architectural colors available for diverse project needs.

  • Simple 1:1 mixing ratio with a pourable and pumpable consistency
  • UV-resistant and maintains color integrity (Dovetail Gray when mixed)
  • High elongation rate (200%) minimizes tearing from movement
  • Provides semi-rigid flexibility without welding slabs together or aging into brittleness
  • Ideal hardness (Shore A = 85) supports wheel load transfer and allows moderate movement
  • Applicable and cures in temperatures as low as -20°F
  • Faster setting and curing times than traditional epoxy fillers, leading to quicker project completion

Tech Sheet
Safety Sheet
Sell Sheet


Primary Uses:

  • Industrial and Commercial Flooring
  • Control and Construction Joint Filling
  • Crack and Joint Repair

Application Instructions: Ensure joints are clean, dry, and devoid of contaminants before application. According to ACI and PCA guidelines, Rapid Flex CJ should fill sawcut control joints to full depth and construction joints to a minimum of 2 inches. The product should not be diluted with backer rod in sawcut control joints and should maintain a minimum depth of 1 inch in all applications.

Mixing and Application:

  • Ensure product temperature is above 50°F before mixing.
  • Use recommended mixing and application equipment to ensure a consistent 1:1 ratio.
  • Overfill joints slightly and allow curing before shaving flush with the floor surface for seamless integration.


Available in 22 fl oz cartridges and 10-gallon units.

Shelf Life

Rapid Flex CJ should be stored in its original containers, kept tightly closed between 55-90°F, ensuring a shelf life of one year from the date of manufacture.


  • Approved for use in USDA, FDA, and CFIA regulated environments
  • Complies with ACI 302 guidelines for “Floor Joint Filler”
  • 100% solid content, VOC-free, and LEED compliant