Underground Infrastructure - February 2023 - 43
EDITION 80 | FEB 2023 | NASSCO.ORG
The process begins when a sewer lateral packer is
aligned with a lateral pipe. An inflatable sock is
inverted into the lateral pipe, and mainline bladders
and sock are inflated, isolating the connection at
three critical points; two in the mainline and one
inside the lateral pipe. Air is then injected into the
void space and, if air escapes, it is considered a
failed joint. Acrylamide grout is then pumped into
the area, flowing through the open joints to the
exterior of the structure. Having a viscosity very
similar to water, the grout also flows into the
annular space between the host pipe and liner.
The grout then gels inside the CIPP annular space
as well as on the exterior of the pipe, creating a
water-tight seal.
Stopping post-rehabilitation infiltration at manholes
is also achieved through injection grouting. A
modern and common practice is to utilize a
hydrophilic rubber seal between the host pipe and
the liner at each manhole termination point. If the
seal was not installed or the host pipe is cracked
at the point of entry, water will enter. Grouting
practices can address these issues by drilling
through the wall of the manhole and installing a
curtain of grout around the structure. The grout
technician will then inject grout into the space
between the liner and host pipe, filling the gap,
and creating a watertight seal.
An added benefit to grouting is the creation of pipe
stabilization and water stoppage within the sewer
trench. A recent study by NASSCO's Infiltration
Control Grouting Committee (ICGC) has shown
that as grout exits the structure, it immediately
drops below the pipe and combines with the
backfill materials to create a gel / soil matrix.
It then fills the void spaces surrounding the pipe in
addition to creating a long-term seal around the
defect or open joint.
Specifications covering Pre-Rehabilitation Grouting
and Capital Grouting practices were released by
ICGC in October 2021 and are available through
the NASSCO website along with an introductory
video on grouting, and a new Unified Safe
Operating Practices Program (USOPP) and
accompanying online exam and recognition of
knowledge. The USOPP is recommended for
handlers, laborers, and inspectors who are involved
in a grouting operation.
To learn more about grouting,
to join ICGC, or to download
specifications, visit NASSCO.org.
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Underground Infrastructure - February 2023
Table of Contents for the Digital Edition of Underground Infrastructure - February 2023
Underground Infrastructure - February 2023 - 1
Underground Infrastructure - February 2023 - 2
Underground Infrastructure - February 2023 - 3
Underground Infrastructure - February 2023 - 4
Underground Infrastructure - February 2023 - 5
Underground Infrastructure - February 2023 - 6
Underground Infrastructure - February 2023 - 7
Underground Infrastructure - February 2023 - 8
Underground Infrastructure - February 2023 - 9
Underground Infrastructure - February 2023 - 10
Underground Infrastructure - February 2023 - 11
Underground Infrastructure - February 2023 - 12
Underground Infrastructure - February 2023 - 13
Underground Infrastructure - February 2023 - 14
Underground Infrastructure - February 2023 - 15
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Underground Infrastructure - February 2023 - 18
Underground Infrastructure - February 2023 - 19
Underground Infrastructure - February 2023 - 20
Underground Infrastructure - February 2023 - 21
Underground Infrastructure - February 2023 - 22
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Underground Infrastructure - February 2023 - 24
Underground Infrastructure - February 2023 - 25
Underground Infrastructure - February 2023 - 26
Underground Infrastructure - February 2023 - 27
Underground Infrastructure - February 2023 - 28
Underground Infrastructure - February 2023 - 29
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Underground Infrastructure - February 2023 - 40
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https://www.nxtbook.com/gulfenergyinfo/gulfpub/underground-infrastructure-april-2023
https://www.nxtbook.com/gulfenergyinfo/gulfpub/underground-infrastructure-march-2023
https://www.nxtbook.com/gulfenergyinfo/gulfpub/underground-infrastructure-february-2023
https://www.nxtbook.com/gulfenergyinfo/gulfpub/january-2023
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