Protecting concrete usually means shielding it from the elements of nature or from harsh manmade chemicals. But it’s not just concrete that needs such protection. Corrugated metal pipe, steel surfaces, material hoppers, rail cars and masonry all can come in contact with corrosive or abrasive materials or harsh conditions.
The geotechnical needs of DOTs and other agencies responsible for roads and bridges are vast. Issues include: Culvert repair Soil stabilization Void filling Concrete slab lifting Sinkhole remediation Slope control Slough control in tunneling
Scope of Work: Sealing deteriorated mortar joints and defects in brick manholes by injecting Prime Flex Hydro Gel SX and water using a two-component pump (the M2).
Problem: Deteriorated mortar joints and defects around pipe penetrations allows ground water and soil to infiltrate manholes causing unnecessary treatment, wear and tear on equipment, and cave-ins around the structure.
Solution: Leaks can be sealed and surrounding soil stabilized with injection of Hydro Gel SX, preventing the need for excavation and replacement.
Hydro Gel SX is a hydrophilic, single-component polyurethane resin typically injected with water using a two-component pump that is either fixed ratio (8:1) or variable ratio. This method is called twin streaming. Hydro Gel SX can also be injected as a single component that reacts with groundwater already present. However, experience indicates that less material is used if mixed with water just prior to injection. “Twin streaming” with a two-component pump also generates a better quality gel. A two-component pump that mixes the product just before it enters the wall is needed since it only has a 45-60 second pot life.
Gel Reinforcing Agent can also be added to the water side of the mix. This is a latex additive that increases the strength and flexibility of the Hydro Gel SX. It also helps to reduce shrinkage during dry cycles. Add the Gel Reinforcing Agent at a ratio of 6 to 8 parts water to 1 part Gel Reinforcing Agent. Then use this solution to mix with Hydro Gel SX at 8 parts prepared solution to 1 part Hydro Gel SX using a two-component pump.
Hydro Gel SX can also be used with oakum to seal larger defects or to form a custom fit flexible seal around pipe penetrations. (See Activated Oakum Technique.)
CURTAIN WALL GROUTING
Injecting a hydrophilic, water-activated polyurethane resin into the outside of the manhole will allow the material to migrate and soak into and against the leaking mortar joints and around pipe penetrations, creating an impenetrable gel or foam curtain while also stabilizing the loose soils surrounding the manhole.
IDENTIFY LEAKS & DEFECTS
Start with the leaking areas and after sealing, check for infiltration that has migrated to other areas.
DRILLING & INJECTING
Materials List (Items listed below in bold are available from Prime Resins):
Rotary hammer drill
1/2” drill bits for stainless wall stinger nozzle
Two-component low pressure pump (M2 Pump system)
Flathead screwdriver (for applying oakum)
Hammer (for seating wall stinger)
Chemical resistant gloves
Activated Oakum Technique