Reports on the Longevity and Effectiveness of Chemical Grouting of Sewers & Manholes
source: www.nassco.org
The members of NASSCO want you to know that chemical grouting is an effective process for stopping groundwater infiltration into sewer collection systems. Chemical grouting is not a structural repair. Chemical grout stabilizes the soil and forms an impermeable mass outside of leaking pipe joints and manhole walls … thereby stopping infiltration. The following is intended to document that chemical grouting is effective and long lasting. The case studies contained herein have been taken from numerous engineering and municipal publications.
Hollywood, FL
In 1981, urethane gel was used to grout the city’s sewer lines. The joints were retested in 1982. In 1985, several joints were dug up and inspected by the EPA. The city affirmed there were no problems with the grout’s effectiveness as of September, 1987.
El Lago, TX
Frank Adams reported in 1985 on the sealing of a 42″ storm sewer by Naylor Industries in 1977. Urethane foam grout had been used successfully to seal the joints and stop the cave-ins of streets and sidewalks above the storm sewer.
St. Louis, MO
In 1984, Bill Skinner reported on the sealing of 14 pipe-to-manhole seals in 7 manholes. Twelve gallons of urethane foam grout was used. Exfiltration tests showed no leaks after several hours with water to the top of each manhole.
Neenah, Wl
John Wilke, City Engineer, reported in 1984 on a 9 routing contract with urethane gel and diatomaceous earth in 1982. None of the grouted joints had leaked.
Lakeland, FL
Grouting of sanitary sewer joints in 1982 with urethane gel grout has reduced flows by 1,000,000 gpd and permitted an additional 3,700 service connections. Effectiveness confirmed in 1987.
Donnelly, Conklin, Phipps & Buzzell Report
In 1981, Gerald Conklin published an article on the EPA study conducted on 18 cities with sewer rehab projects done in the 1970’s. The cities were all over the United States. The article reported that TV inspection revealed that chemical grouting was generally successful in sealing out groundwater. The remaining infiltration/inflow was from sources other than the grouted joints.
Minneapolis, MN
Manholes grouted in 1980 with urethane foam grout and oakum, plus urethane gel grout, successfully sealed and effective through 1987.
Hollywood, FL
Manhole grouting done in 1981 with urethane gel grout on brick manholes, some near 25 years old, reported to be effective in 1987.
Albany, GA
In 1984, Billy Daniel reported on the successful use of urethane gel grout to seal brick and concrete manholes in high groundwater areas of the city. Leaks of 2-100 gpm had been stopped. Grouting saved replacement of manholes and reduced flows at the treatment plant.
Ontario, Canada
David Robichaud, Underwater Tel-Eye, reports in 1988 that UTE has never had to regrout a sewer joint due to grout failure. UTE has used chemical grout for over 15 years and they use grout concentrations exceeding the standard recommendations. This major Canadian contractor has utmost confidence in its ability to permanently seal sewer pipe joints.
Little Rock, AR
Large-diameter pipe grouting with urethane foam in 1973 was confirmed to be effective in 1987. The 60-inch sanitary sewers under the Municipal Airport were built in the 1930’s and about 1900 joints had remained sealed.
Plaquemine, LA
Grouting of 48″ to 72″ storm sewers in 1975 was reported to be effective in 1987. Urethane foam grout was used with a large-diameter packer. Approximately 650 joints were sealed, eliminating surface subsidence.
Orlando, FL
Greiner Engineering Services presented a paper in 1985 on a project involving grouting of 36″ to 48″ storm sewers under runways at the International Airport. Urethane foam and acrylamide grouts were used to seal the joints; cement was used to fill voids under the runways. The project was several years old at the time and long-term success was predicted.
Oakdale, MN
Cost-effective repair reported in 1987. Manhole repaired with urethane foam and oakum, plus urethane gel in 1980.
The information contained herein has been taken from published studies and written reports. NASSCO members hope that you have a better understanding of the longevity and effectiveness of chemical grouting… when done correctly.