Duopatch Two-Component Polymer-Modified Concrete Repair Mortar

Application

Surface Preparation

• Ensure Cleanliness: The concrete must be clean and free from oil, grease, dust, laitance, or any surface contaminants. Mechanically abrade the surface to a minimum Concrete Surface Profile (CSP) of 3 as per ICRI 310.2 standards.
• Create Notched Edges: For enhanced durability in heavy load or high traffic applications, saw cut a ¼” recess around the perimeter of the patch, forming a thickened edge.
• Moisture Condition: The concrete surface must be saturated-surface-dry (SSD) with no standing water present.
• Steel Reinforcement Cleaning: Remove rust from all exposed steel reinforcing and apply SpecPrep SB as a protective coating.
• Priming: Apply SpecPrep SB to SSD concrete via spray or brush, ensuring the repair mortar is applied wet on wet or within the open time specified in the SpecPrep SB datasheet. Alternatively, use a scrub coat of mixed repair mortar, ensuring it is placed before the bond coat dries.

Mixing and Application

• Measure 7.0 to 7.5 pints of Duo Patch Admix per 50-pound bag, adjusting based on desired consistency.
• Use a low-speed drill for mixing. Begin with the Admix, then gradually add the Duo Patch powder, mixing for 2-3 minutes until homogeneous. Do not mix more material than can be used within the product’s setting time.
• For repairs up to 1” thick, apply Duo Patch directly. Do not exceed 7 pints of Admix for depths over 1/2″.
• For larger repairs over 1”, extend Duo Patch with up to 60% by weight (30 lbs) of clean, SSD 3/8″ aggregate, mixing for an additional 2 minutes. This mix should be placed within 15-20 minutes.

Placement Procedure

Apply Duo Patch into the prepared area with a trowel, screed, or pour, ensuring full contact and integration with the surface. For a level finish, screed Duo Patch flush with the surrounding concrete.

Finishing/Curing

After initial set, when Duo Patch is firm, finish with a hand trowel to match the surrounding concrete texture. Use SpecChem IntraFilm as a finishing aid if needed. Under most conditions, Duo Patch is self-curing. In extreme conditions, apply an ASTM C309 compliant SpecChem water-based curing compound.

Packaging

DUO PATCH is available in two packaging options:

• A 50 lb bag with a 1-gallon jug of DUO PATCH Admix.
• A 60 lb pail unit, containing a 50 lb bag of DUO PATCH and a 1-gallon jug of DUO PATCH Admix.

Shelf Life

Unopened bags of DUO PATCH have a shelf life of 12 months when stored in a dry area. Store in a cool, dry location away from direct sunlight to maximize shelf life. Ensure the DUO PATCH Admix does not freeze.

Test Data

• Set Time at 70°F (according to ASTM C266): The initial set time is approximately 40 minutes, with a final set time around 50 minutes.
• Compressive Strength (as per ASTM C109):
  • At 1 day, the compressive strength reaches 2,500 psi.
  • At 7 days, it increases to 4,000 psi.
  • By 28 days, the strength peaks at 6,000 psi.
• Bond Strength (following ASTM C882 modified): After 7 days, the bond strength is measured at 1,800 psi.
• Length Change (based on ASTM C157):
  • Wet Cure at 28 days shows a slight expansion of +0.04%.
  • Air Cure at 28 days indicates a minor contraction of -0.02%.
• Flexural Strength (according to ASTM C348):
  • At 7 days, the flexural strength is 650 psi.
  • At 28 days, it rises to 1,300 psi.
• Yield: Each bag yields approximately 0.42 cubic feet.

Cleaning

Clean tools and equipment with water before the DUO PATCH hardens. Following these steps ensures a smooth application process and extends the life of your tools.