GeoTree - Rehabilitation Of 72-inch Brick Combined Sanitary/Storm Sewer

Maintaining centuries-old underground infrastructure presents a significant challenge when structural failures occur beneath busy municipal corridors. When a pavement void signaled a cracked crown and missing bricks in a 72-inch brick combined sewer, traditional replacement options were ruled out due to extreme cost and severe surface disruption. Standard cured-in-place pipe (CIPP) lining was also impractical, as it would have required the complete removal of manholes within a heavily trafficked business and tourist district.

To minimize community impact, engineers turned to a high-performance geopolymer mortar applied via an advanced trenchless spincasting system. Operating entirely at night allowed teams to work during low-flow hours, utilizing a compact equipment footprint that left surrounding lanes open during the day. The host pipe was pressure-washed, stabilized with hydrophobic grout, and lined with a minimum 2.5-inch structural layer enhanced with welded wire reinforcement. Because the geopolymer cures rapidly, normal sewer flow was safely restored by morning, preventing daytime service interruptions.

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