Here, you’ll find answers to the most common questions about using Five Star® products.

Should you still have questions after reviewing the FAQs, please call our Engineering and Technical Services line at 1-800-243-2206 (in the US or Canada) or +1 203-336-7900 (outside the US or Canada).

Precision Epoxy Grouts

Five Star® DP Epoxy Grout and HP Epoxy Grouts are designed for aggregate reduction and have published physical properties based on a specified aggregate reduction (4 bags of aggregate instead of 5).

All Five Star® Precision Epoxy Grouts (except Fluid Epoxy) are 3 component systems consisting of 2 liquid components (Resin & Hardener) and aggregate. First, the two liquid components must be combined and mixed using a SLOW speed drill with paddle attachment. Once the liquids are thoroughly mixed (no streaks or color differentiation), they are placed in a mortar mixer (not a concrete or cement mixer). With the mixer running, the appropriate amount of aggregate is added and mixed until the aggregate is thoroughly wetted with the liquids (approximately 2 minutes).

Refer to Technical Bulletin 210 (fka110) Proper Compressive Strength Testing for complete details. Most often, a cause for low breaks is that the compression tester used is not set up to break epoxy grout cubes. The load rate, as Specified in ASTM C579 Method B, is mandatory for getting an accurate break result. Any other load rate will not result in a “true” break and often result in lower strengths being reported.

Five Star® Fluid Epoxy can flow down to ⅛ inch (3.2 mm) clearance, and Five Star® LC Epoxy Grout can flow down to 0.40-inch (10 mm) clearance. If used in high-volume applications, contact Five Star Products.

Five Star® XP 230 Epoxy Grout, DP Epoxy Grout PG, and SP Epoxy Grout PG can be pumped using a peristaltic and rotor-stator pump. Standard everyday grout pumps designed to pump cementitious grouts will not work with epoxy grouts.

Five Star® DP Epoxy Grout High Flow is available in a .44 cu ft unit for small volume pours. Units of Five Star® Precision Epoxy Grout are not recommended to be proportioned to smaller mix quantities.

Precision Cementitious Grouts

Five Star® Precision Cementitious Grouts can be placed from ½” (12 mm) to 6” (150 mm). Refer to individual product Technical Data Sheets for exact placement depths. All products can be extended with aggregate for deeper pours. For additional information, refer to Technical Bulletin 105 Aggregate Extension Guidelines for Cementitious Grouting.

Five Star® Precision Cementitious Grouts require a 3-day continuous wet cure (exceptions are Five Star® Instant Grout and HTR Grout) or a minimum 24-hour continuous wet cure followed by an approved curing compound application. In-service grout operation may begin immediately after the required grout strength has been reached.

Cold temperatures delay set time and strength development of cementitious grouts. Cementitious grouts must be allowed to attain a minimum compressive strength before being subjected to freezing temperatures. Grout temperature shall be maintained above 40°F (4°C) until the grout reaches a minimum compressive strength of 1000 psi (6.9 MPa). Depending upon the grout mix temperature and thickness, this may take up to 48 hours. Curing grout below 40°F (4°C) will delay grout strength development. For further information, refer to Technical Bulletin 101 Cementitious Grouting in Cold Weather.

Storing the material in a cool environment and using iced water will extend the working time of Five Star® Precision Cementitious Grouts.

To properly mix Five Star® Precision Cementitious Grouts, a mortar mixer with shearing action is required. The mortar mixer shall be clean, dry, and in good working order and shall be sized appropriately for the cementitious grout pour. The mixing volume is recommended not to exceed ½ of the mixer’s total volume. Large-volume placements may require multiple mortar mixers. Contact your local Five Star Technical Sales Representative for mixes with coarse aggregate extension. For more information, refer to Technical Bulletin 406 Recommended Mixers for Cementitious Materials.

Generally, no. A bonding agent is unnecessary if the concrete surfaces can be presoaked for 8-24 hours before grouting. Bonding agents are only helpful for grouting applications where presoaking cannot be achieved.

Five Star Products assigns a 10-digit lot number to all its cementitious products. This lot number is on the bottom of a bagged product or the side of a pailed product. The last four digits represent the day and year of manufacture. Five Star Products uses the Julian calendar to assign the day. The Julian calendar is a 365-day calendar, starting on January 1, with day 001. To obtain the manufacturing date, look at the last four digits of the lot number. The manufacture day is Julian day 142. By accessing the Julian Calendar chart below, 142 corresponds to May 22nd. The manufacturing year is represented by the last digit, – 3, which would be 2023. Thus, lot number 5053401423 was made on May 22, 2023. Refer to the current Five Star® Technical Data Sheet for the product’s shelf life. If your product is beyond the shelf life date, as determined by the lot number, do not use it. Properly dispose of all unused Five Star® products.

To view the Julian Calendar, see Technical Bulletin 409: Determining Manufacture Date for Five Star® Cementitious Products.

Concrete Rehabilitation & Repair

Set time and working time for cementitious materials are quite different. SET TIME is defined as the degree of stiffening of the cementitious mixture such that it resists the penetration of a weighted needle to a pre-determined depth (i.e., well past the flowable state). WORKING TIME is the period the grout can be placed after mixing (i.e., still in a flowable form). It is estimated by performing consistency tests at intervals after mixing. The consistency of the grout towards the end of its working time will be stiffer than when initially mixed. Working time is always less than set time.

No, Feather edging is not recommended, as this is where failure often occurs. Minimum depths for Five Star® Concrete Rehabilitation & Repair Products vary from ¼ inch (6 mm) to greater depths depending upon loads and traffic-bearing conditions.

Depending upon the repair area geometry and size, Five Star Structural Concrete® V/O can be applied in lifts of approximately ½ (12 mm) to ¾ inch (19 mm). Additional lifts may be applied by immediately scoring the surface of newly placed material in a checkerboard-type pattern and then allowing it to stiffen just enough to hold another lift.

No, a primer or bonding agent is not required with Five Star® Concrete Rehabilitation and Repair products, provided the substrate has been mechanically roughened and properly presoaked. However, Five Star® Bonding Adhesive may be used on dry substrates (where presoaking cannot be accomplished) or to further enhance bond development on large overlays.

Moisture-sensitive coatings can typically be applied in 8-24 hours, depending upon the product and curing conditions. Refer to the moisture requirements from the coating manufacturer and contact Five Star Products for more detailed recommendations.

If you haven’t found an answer to your question, please contact Five Star Products at 1-800-243-2206 (in the US or Canada) or +1 203-336-7900 (outside the US or Canada).