Grout Workshop: Stop Water Infiltration Now, Not Later

By Traci Read, Senior Editor | July 2010 Vol. 65 No. 7

To get the workshop rolling, attendees were asked, “Would you like to spend $3,000 now to save $200,000 later?” They would learn that grout – used for more than 50 years as an effective method for eliminating ground water infiltration into sanitary sewer systems – is less expensive and less disruptive than other rehab methods.

Industry experts Magill and Dick Schantz, P.E., Aires Industries product manager, gave presentations on six areas:

  • Understanding sewer system chemical sealing programs and specification information;
  • Why chemical grouts are economical and effective at stopping groundwater infiltration;
  • How chemical grouts permanently stop groundwater infiltration into existing sewer systems;
  • How chemical sealing stops groundwater infiltration at service lateral cutouts in lined sewers;
  • Why sewer joint testing and chemical sealing should be a scheduled sewer maintenance; and
  • Municipal case studies of successful grouting programs.

Dr. C. Vipulanandan, Ph.D., P.E. and director of CIGMAT, provided an overview of grouts being studied and tested at the University of Houston’s Department of Civil and Environmental Engineering. “Testing and field results by CIGMAT have validated the applicability of grouts to eliminate infiltration into our cities’ sewer systems,” says Vipulanandan.

Live demo
Using an Aries’ TV/grout inspection truck and camera plus a Logiball packer, a simulation of the grouting process was conducted by Schantz.

Grouting a sewer line’s joints involves a particular process, Schantz pointed out. A crew uses a CCTV camera that enables a trained technician inside the truck to view pipes a thousand feet in any direction from a manhole. Where joints need grouting, a technician pulls a packer that is connected by an air hose to a compressor on the truck through a sewer line. The packer has four lines – two for acrylamide chemicals and one for air testing.

“If the joint fails the air test, then it will be sealed,” adds Schantz. “The technician inflates the packer and pumps the two acrylamide chemicals through it. The two chemicals combine, travel through the crack or joint, and permeate the soil outside the pipe where it cures to an impermeable solid in a controllable time-period, stopping infiltration. Then the joint is air-tested again to confirm that the joint has been sealed.”