Q: What kind of inspection is needed on site?
A: Our ICBO ER-5645 report states that “special inspection” is required. This means that a quality assurance technician should check the rebar anchor dowel lengths to make sure they meet the minimum embedments specified in the User’s Manual. The technician should monitor the grouting operation to verify that all sleeves have been filled and the grout mixed properly. Finally, they should take 2” cube specimens of the grout to test before the removal of bracing and at 28-days.

Q: Can the testing lab use plastic cube molds?
A: No, they must use heavy brass molds with cover plates.

Q: Can the lab use the same testing apparatus as they use for concrete cylinders?
A: No, the test machine must be fitted with the proper supports for 2” cubes. The test values are very high (reaching 14,000-psi) and ASTM procedures must be strictly followed.



Q: How do we know if the sleeve is filled?
A: The proper grouting procedure is to pump into the lower inlet port and catch the grout in a cup. The sleeve should be over-pumped by a few strokes to show that all the air has been pushed out and only a smooth flow of grout is coming from the upper outlet port. Then, stop pumping, wait for the flow to subside and immediately put a stopper in the upper port. This insures that the grout cannot backflow. Remove the nozzle and put a stopper in the lower inlet port.

If you are doing Pre-Grout sleeves, you can look down inside and see that the sleeve is filled with grout. If the grout is somewhat stiff, use a wire to stir it to remove any entrapped air at the very bottom. Shooting the grout down in the sleeve with the grout pump nozzle is a good alternative to pouring it by hand. It’s faster, too.

Q: How do we know the strength of the splice?
A: The performance of the NMB is related to the embedment length of the bars and the compressive strength of the grout. Charts and data are available to show the effect of bar embedment and grout strength. As long as the bars meet minimum embedment lengths and the grout meets minimum compressive strengths, the splice will perform as specified.