Potholes and cave-ins are often caused by leaks into storm and sanitary sewer lines. Cracks, improperly installed or failed joint seals, settling, and misalignment can all create entry for ground water into the sewer system. As ground water flows in, it usually washes away surrounding soils. Eventually, large voids are created around the pipe and the surface soil settles or collapses to fill the voids.
Municipalities all over the country have discovered that leaking pipes can often be sealed permanently without expensive excavation. The repair is called “probe grouting.” A small diameter pipe is driven down from the surface to the vicinity of the leak. Then, a Prime-Flex hydrophobic water-reactive polyurethane grout is injected through the pipe. A camera can be placed in the line upstream from the repair to monitor the grouting process. When the crack or joint is sealed, the probe pipe is withdrawn. Any excess grout material in the sewer line can be easily removed by cutting or water jetting