Capitol Tunneling is pleased to partner with Grout Solutions to offer a lightweight cellular grout for filling annular spaces. Our cellular grout can also be used for ground stabilization and total pipe abandonment. The cellular grout is significantly lighter than traditional sand grouts which allow us to pump it for further distances. On average, the grout’s unit weight averages 35 lbs per cubic foot, which is 100 lbs. per cubic foot less than traditional sand grouts. This reduces buoyancy concerns when backfilling the annulus between a tunneled or bored casing and the carrier or between a host pipe and a liner pipe in a slip-lining installation. The 200 psi strengths at 28 days provides ample strength to secure carrier pipe without risk of flotation and an engineered fill that has greater strength than the in-situ soils.

The grout mix can be modified to allow for its use in several applications. We primarily use it as an annulus backfill, soil stabilization, ground consolidation, and pipe abandonment. It can also be used as a load reducing/balancing fill over poor soil conditions, as a backfill around bridge culverts or approach slabs, underground voids, structure, or cavern fills, as an insulator, and sub-base for landscaping applications. The grout can be made to be permeable or non-permeable. Installation of the grout can be either by gravity filling or the mix is pump-able using progressive cavity pumps.

All of Capitol Tunneling’s crews have been trained and are able to perform the grouting operation. Call us today to discuss how our grouting expertise can help you.