An experimental study was conducted to evaluate the performance of various filler materials used in Type B tight-fit and stand-off steel sleeve designs. Full-scale testing was performed to examine the performance of three filler materials and two sleeve types reinforcing four separate dents subjected to cyclic internal pressure. All filler materials were installed with the test pipe at 55°F and allowed to cure for 7 days. The metric for comparing filler material performance was stress concentration factors (SCFs) measured in the dents in the unrepaired and repaired configurations. The filler materials included a two-component epoxy, an epoxy-based grout, and a cement-based grout. The average SCF for the unreinforced dents was 5.64, while after reinforcement the average SCF was 1.2 (an average reduction of 79%).
The results of this study generated two important findings. First, the stand-off sleeve design was able to provide reinforcement similar to what was measured for the tight-fit sleeve. Second, the study determined that the cement-based grout actually slightly outperformed the epoxy-based grout, the latter being the filler material of choice prior to this study. This paper provides readers with practical information and data on the performance of competing filler material types, while also presenting a systematic method for evaluating different methods of reinforcement.
