Grout Workshop: Stop Water Infiltration Now, Not Later

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

Most sewer infiltration enters structurally sound sewer systems through joints, manholes, service connections and the first few feet of the service lateral. Infiltration occurs when defects in below-grade structures like sanitary sewer lines, manholes, pump stations, catch basins or storm drains allow ground water to enter the system. This infiltration adds to treatment costs and increases the risk of sanitary sewer overflows (SSOs). A proven and economical way to permanently stop these leaks is with chemical grout.

Chemical grouting is a joint sealing and stabilization process used to stop ground water flow through soils surrounding structurally sound sewer pipes or structures such as manholes, lateral cut outs and the exposed annulus flow area between the liner and host pipe. The grouting process involves the injection of low-viscosity grout (the same as water) into the structure or soil. The grout saturates the soil, displacing the water between the soil grains and then gels to form a gel/matrix. This gelling locks up the soil grains thereby stabilizing the soil and prevents water flowing through the soil into sewer cracks and thus into the sewer structure, effectively stopping infiltration.

To teach the basics of grouting, a group of suppliers hosted a half-day workshop for city of Houston personnel and local engineers at the Avanti International offices in Webster, TX (near Houston), on April 27. Avanti (chemical grout supplier), Aries Industries (television and grouting equipment supplier), Logiball (joint and lateral test and seal packers) and the University of Houston’s Center for Innovative Grouting Materials (CIGMAT) sponsored the workshop.

The workshop builds on the popular Grout Boot Camps that are scheduled twice a year in different locations. To date, eight camps have been conducted with more coming in 2011 – one on the East Coast and a new one planned for the West Coast. Representatives from these three firms staff more intensive three-day training schools.

Each of these grouting suppliers are members of the Infiltration Control Grouting Association (ICGA), a division of NASSCO (National Association of Sewer Service Companies).

Program coverage
“Grouting is being done, but not always correctly,” says Daniel Magill, president of Avanti. “The purpose of this workshop is to give personnel the basic knowledge of how to effectively maximize their use of grouting.”