Over time or because of a particular event or condition (e.g., seismic activity, exposure to excessive or uneven loads or moments, exposure to micro-organisms, poor compaction, crown corrosion, corrosive soil, etc.), the structural integrity or capacity of force mains, other pipes and other structures may diminish. For example, such items may crack, corrode, deteriorate and the like. Different methods of repairing or otherwise strengthening damaged pipes and other items are well-known. For example, liners or layers made of fiber reinforced polymers can be attached to one or more portions of a pipe interior. Among other ways, liners of this type can be formed in a tubular shape and dragged in or everted into the pipe to be repaired. Still further, in larger diameter pipes, the lining may be formed by manually adhering sheets of repair material to the walls of the pipe.
Certain high-strength liners or sheets are made of woven fibers of glass, carbon, aramid, or the like impregnated with a polymeric matrix that is, in some embodiments, cured in place. The woven fibrous material typically has a relatively open or loose weave that is water permeable in the absence of the polymeric material. Though the polymeric material in most instances prevents groundwater from infiltrating a pipe for a time, pinhole leaks are known to form in the openings between the woven fibrous strands under certain conditions. Pinhole leaks let undesirable groundwater enter the pipe. Moreover, high strength liners are often used to line pipes that carry pressurized fluids. Pressurized fluid can easily escape through pinhole leaks and cause further damage to the liner.