Mainline Grouting

Mainline grouting is executed using a grout truck, inflatable mainline packer, and a two-component chemical grout. From the grout truck, an operator controls all aspects of injection grouting. Closed-circuit television (CCTV) is utilized inside the pipe to locate the joint, defect or crack to be tested and/or injected, and strategically positions the packer in place. It is important to air test all joints because joints that were not visibly leaking during inspection may leak in the future after sealing surrounding joints. Joints that fail the air pressure test can immediately be injected and sealed with grout. Grout is forced under pressure through the defect into the surrounding soils forming a waterproof barrier that cannot be permeated. The operator will pump until grout is no longer accepted through the defect (refusal). After the joint or defect is sealed, a post-air pressure test is administered. If the defect does not leak air, it will not leak water. Once the joint is documented, the packer is deflated and moved to the next defect in the pipe to repeat this process. Residual cured grout left behind in the pipe will breakdown as it cycles through the system. Once cured, grout is inert and non-toxic.