Springfield, MA
GeoSpray® Geopolymer: Hand Laid Brick Sanitary Sewer Rehab

Project Overview
Springfield Water and Sewer Commission was issued successive Administrative
Orders by the EPA in 2008 and 2012 to reduce Combined Sewer Overflows (CSOs) in the Washburn Street CSO Area. As a part of this effort the City of Springfield identified 2,780 linear ft of hand laid brick sewer that needed to be repaired. The pipe was located in the downtown district under nearly 60 ft of cover and ran under several existing buildings. The original brick sewer had an inner diameter of approximately 66 inches.

The existing brick sewer was in poor condition. Many segments of the sewer had
missing or lost brick in the spring-lines, crown and invert. The first step in the process was to clean the pipe with a high pressure water cleaning system and the to repair with hydraulic cement any of the sections of the pipe that were missing bricks. Once the sections were repaired and the active infiltration was stopped, a first ¾ inch layer of GeoSpray® mortar was applied via a mechanical sled spraying systems. 

After the first layer of spray was applied and cured, the carbon grid was then applied to the spring-lines and a second pass was competed. The final carbon grid application to the crown and invert were applied and the final thickness was achieved.

One key aspect of this project was the many incoming lateral service lines. Because this was an active sewer line, large scale by-pass of these connections was not possible. Because of the flexibility of GeoSpray mortar and the application process the contractor was able to temporary plug lines for a few short hours, informing residents that they could use their sewer flows with restricted flow and then remove the plugs within the same day.

Finally, the project was conducted over the cold winter months and surface
temperatures at time dipped to nearly 0°F. While the contractor was able to take precautions to install GeoSpray mortar at low temperatures, the fact that GeoSpray mortar will not form a cold joint between different spray applications allowed the city and the contractor to delay completion of the job until the weather was above freezing without any effect on the final structural pipe.

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