48 Inch RCP Joint Repair
The Job
This 48 inch RCP joint repair project is located in Raleigh, North Carolina. The pipe is located at a commercial facility. The slope covering the pipe experienced a slope failure. Upon inspection, six joints were showing signs of soil infiltration and water exfiltration.
The Challenge
The primary challenge for the general contractor on this project was minimizing cost and time. It would have been expensive and disruptive to excavate the pipe. Cover depths were up to 15 feet, and there was a road that would be impacted by excavation, as well.
The exfiltration from the leaking joints was washing away bedding material and adjacent backfill. This caused significant amounts of erosion, and destabilized the slope soils by completely saturating them.
Piping outside of reinforced concrete pipe is an ideal candidate for polyurethane grouting.
The Solution
CJGeo worked with the general contractor and owner’s civil engineering to design a grouting program to repair the pipe. The general concept for this 48 inch RCP joint repair project was to backgrout the pipe with rigid geotechnical polyurethane grout. CJGrout 35NHV61 was the grout of choice; it can be injected directly into flowing water, provides nearly 10ksf in compressive strength, and migrates into both large and small voids with ease.
A CJGeo polyurethane grouting crew took a single day to perform the repair. The average circumferential void around the pipe was nearly nine inches. Cutoff criteria were:
- grout hole to joint communication
- cross hole communication
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Facing a similar challenge to this 48 inch RCP joint repair project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
North Carolina Abandonment Grouting
The Job
This North Carolina pipe abandonment project is located in Raleigh, North Carolina. It is part of the Upper Walnut Creek sewer replacement. After installation of a new gravity sewer, more than three miles of 42″ sewer was requiring abandonment grouting. The specification calls for completely filling the pipe with controlled low strength material (flowable fill).
The Challenge
The primary challenge for the general contractor on this project was minimizing cost and time. The owner’s specification calls for an NCDOT-approved flowable fill material. Most flowable fills can only be placed for up to a few hundred feet before requiring another access point. The contractor wanted to minimize the number of placement points to ensure the fastest placement possible.
The Solution
CJGeo designed a grouting program using one of our NCDOT-approved mixes. Using dry batch generation, CJGeo can make up to 200 cubic yards per hour of material, which is enough to fill 562 feet of 42″ pipe per hour.
CJGeo mobilized a dry batch cellular grout plant to the site, and made a total of 5,539 CY of cellular concrete to complete this North Carolina abandonment grouting project over a few weeks. Some of the pipe was completely full of water. Even though cellular grout is significantly lighter than water, it can still displace water out of pipes.
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Facing a similar challenge to this North Carolina abandonment grouting project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Virginia Pipe Abandonment
The Job
This Virginia pipe abandonment project is located in Norfolk, Virginia. It is part of the HRSD’s capital improvement program. After installation of a new gravity sewer, 875 linear feet of 24 inch sewer required grout filling for abandonment.
The Challenge
The primary challenge for the general contractor on this project was avoiding installing placement points every 150 feet to use traditional flowable fill. The owner’s specification if using traditional flowable fill requires placement points every 150 feet. The owner allows other controlled low strength materials to be pumped further, as long as uniform material vents at the far end of each placement.
The Solution
CJGeo proposed using 30lb/cuft CJFill-Ultra Lightweight cellular concrete. CJFill-Ultra Lightweight is pumpable thousands of feet per placement. This eliminates the need for most intermediate access points.
CJGeo mobilized a wet batch cellular grout plant to the site, and made 101 CY of cellular concrete grout to complete this Virginia pipe abandonment project in a few hours. The pipe was completely full of water. Even though cellular grout is significantly lighter than water, it can still displace water out of pipes.
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Virginia Lightweight Fill
The Job
This Virginia lightweight fill installation is located Norfolk, Virginia. The placement is part of a low income housing development in an area subject to flooding. The site is located a few blocks from downtown Norfolk.
The Challenge
Like many coastal cities, much of the ground in Norfolk is infill. On this site, fill material was entirely uncontrolled. It included construction debris, organics, and silty sands. In order to bring the finish floor elevations above flood elevation, the site needed to come up by nearly eight feet in some areas.
The Solution
CJGeo worked with the structural engineer to design a lightweight backfill program that would help reduce anticipated settlements. After stone columns were installed across the site, the CMU building walls were built on poured footings. After the walls were in place, CJGeo filled the entire building pads with Ultra Lightweight CJFill, with an average density of 25lb/cuft.
CJGeo batched CJFill-Ultra Lightweight with a 80psi at 28 day minimum compressive strength using the dry batch process onsite, and placed at times more than 1,000 cubic yards per day.
Once the CJFill-Ultra Lightweight was in place, plumbers trenched in plumbing, and placed twelve inches of sand on top of the CJFill-Ultra Lightweight. The work took around two weeks, using the dry batch generation method.
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Facing a similar challenge to this Virginia Lightweight Fill project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Box Culvert Void Filling
The Job
This box culvert void filling project is located near Fredericksburg, Virginia. The Virginia Department of Transportation owns and maintains the structure, which conveys a stream under a rural divided highway. As part of a rehabilitation project, extensive cracking in the structure (a double barrel six foot by six foot box), was being patched with repair mortar, and some cracks epoxied.
The Challenge
At the start of project, the general contractor discovered extensive voids outside of the structure. These voids were allowing significant amounts of the stream flow outside of the box culvert (piping). This was cause for concert regarding the specified repair mortar application and epoxy injection.
The general contractor reached out to CJGeo about filling the voids with grout prior to the patching and repair operation.
The Solution
CJGeo proposed grouting all the voids outside of the box culvert with CJGrout 35NHV61. 35NHV61 is a hydro-insensitive, structural polyurethane grout. Its NSF61 potable water certification makes it excellent for work on drainage structures.
The owner, Virginia’s Department of Transportation, required water testing before, during and after grouting. This water testing specifically looks for MDI. All of the water testing, which was performed by a third party environmental laboratory, found zero MDI in any of the water samples.
It took three days onsite to complete the grouting. Some hairline cracks that were still damp after the bulk box culvert void filling work. CJGeo grouted these cracks with a hydrophilic chemical grout to make them completely dry.
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Facing a similar challenge to this box culvert void filling project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Stormwater Sinkhole Repair
The Job
This stormwater sinkhole repair project is located at a data center near Dulles, Virginia. Within a few months of construction, a depression started over a utility intersection within a street intersection inside the fence. Time showed that asphalt patching wasn’t going to solve the problem, so a geotechnical engineering firm was brought into investigate the sinkhole.
The Challenge
The first step taken was video inspection of all the gravity utilities in the area. None of them were showing any signs of leaks of water or soil. Utilities within the zone of influence of the sinkhole include:
- stormwater (deepest & largest)
- fire protection
- two fiber duct banks
- three electrical duct banks
Given the shear number and crossing alignments of utilities, and lack of leaks, the presumption was that backfill consolidation over the underlying stormwater structure was the most likely cause of the settlement.
The Solution
Due to the presumed cause of inadequate compaction, the geotechnical engineer recommended polyurethane compaction grouting to the owner. Compaction grouting with polyurethane grout is significantly faster, less disruptive, and less likely to displace adjacent structures than cementitious compaction grouting.
CJGeo proposed using CJGrout 20SDB for this stormwater sinkhole repair project. 20SDB is well suited for filling bulk voids, and has very little expansive pressure, so minimizes the chances of fouling or damaging the adjacent critical utilities.
A CJGeo polyurethane grouting crew was able to complete the repairs over two days onsite.
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Facing a similar challenge to this stormwater sinkhole repair project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Maryland compaction grouting
The Job
This Maryland compaction grouting project is located on East West Highway, in Chevy Chase. A few years after finishing construction of a new mixed use building with underground parking, the public sidewalks began to settle.
The Challenge
A local consulting geotechnical engineer was the first call by the building owner. After reviewing the construction drawings, and visiting the site, the geotech recommended performing a few hand augers. The hand augers were to:
- confirm the sidewalk construction matched the plans
- check for bulk voids below the sidewalk
- confirm the backfill material
- see just how loose the backfill material was.
The hand augers confirmed that the sidewalk was indeed pavers over asphalt, over a thin concrete mud slab. There were sporadic voids below the mud slab, up to six inches deep. The backfill material was poorly controlled soil, and was relatively loose.
The Solution
Due to the backfill material being relatively loose, and the building being new enough that the soils hadn’t consolidated on their own, the geotechnical engineer recommended polyurethane compaction grouting to the owner. Compaction grouting with polyurethane grout is significantly faster, less disruptive, and less likely to displace adjacent structures than cementitious compaction grouting.
CJGeo proposed using CJGrout 20SDB for this Maryland compaction grouting project. 20SDB is well suited for filling bulk voids, and has very little expansive pressure, so minimizes the chances of fouling or damaging drainage board.
A CJGeo polyurethane grouting crew was able to complete the repairs over two days onsite.
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Facing a similar challenge to this Maryland compaction grouting project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
SOE Closure Manchette Grouting
The Job
This SOE closure Manchette grouting project is located in Alexandria, Virginia. It is part of the RiverRenew project, a large CSO project.
The Challenge
As part of this project, a diversion structure and drop shaft were being installed to pull flow off of an existing sewer tunnel. The box tunnel is around 8′ wide. The SOE will facilitate installation of the diversion chamber. Excavation within the SOE called for closing the gap between slurry wall panels. This is to be done under the existing structure with steel lagging.
However, the closure is below ground water table. The “marsh” deposits soils require stabilization prior to excavation. The conceptual design from the owner called for permeation grouting tied into an underlying clay layer. The clay layer is approximately 50′ below existing grade.
The Solution
CJGeo proposed performing the permeation grouting to cut off ground water flow and stabilize the soils for excavation using an acrylic grout. Due to the relatively deep required depth, traditional percussion driven installation tubing wasn’t possible.
To ensure accurate placement at depth, CJGeo used the TAM grouting method. TAM grouting, or Tube-a-Manchette, uses special grout casing installed by drilling to grout through.
CJGeo performed this SOE closure Manchette grouting work over a period of two weeks.
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Facing a similar challenge to this SOE closure Manchette grouting project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Massachusetts Lightweight Fill
The Job
This Massachusetts lightweight fill project is located at Boston’s Logan International Airport. It is part of Logan Forward continuing improvements to the airport.
The Challenge
As part of this project, the general contractor installed two cast-in-place barrier walls. The space between the barrier walls is between four and nine feet. The walls are curving, have non-vertical faces, and bear on a curving, non-horizontal existing podium slab. The gap between the walls needed to be filled in order to pour a housekeeping slab spanning between the walls.
This work is all on an existing podium structure. So, the fill density between the two walls had to be as low as possible.
The Solution
CJGeo proposed filling between the two walls with CJGrout 20SDB. 20SDB has a similar density and compressive strength to typical expanded polystyrene (EPS, or Geofoam) blocks. However, unlike geofoam blocks, 20SDB:
- is pumped, so doesn’t require trimming, and fits to any shape
- expanded onsite, so logistics are significantly simpler
- cures within a few minutes, so is still quick
- not affected by petroleum products
A CJGeo polyurethane grouting crew took a single shift onsite to install the 64 cubic yards of CJGrout 20SDB. The general contractor began installing the topping slab the next day.
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Facing a similar challenge to this Massachusetts lightweight fill project? Give us a call or send us an email by clicking on the state marker to locate the Preconstruction Manager that services your area.
Detroit Michigan Annular Space Grouting
The Job
This Detroit Michigan annular space grouting project is located near Van Dyke Avenue & 8 Mile Road. The project owner is Great Lakes Water Authority, and the project is part of the PCI-4 rehabilitation.
The Challenge
As part of the rehabilitation of this large diameter sewer, three different liner systems had to be installed. The longest section of single liner type is approximately 800 linear feet. The concrete sewer’s inner diameter is approximately 17.5 feet. The outer diameter of the liner that the installer subcontracted the annular space grouting to CJGeo on is approximately 16.5 feet.
Based on the theoretical average inside diameter of the existing sewer, the annulus is almost exactly one cubic yard per linear foot.
The Solution
The pipe runs at full charge at least once per day, so there was a high likelihood of accumulated water in the annulus. To displace this water and ensure consistent bearing of the pipe, CJGeo proposed 75lb/cuft CJFill-Under Water. While this density of CJFill cellular grout significantly exceeds the 300psi at 28 day compressive strength requirement, it facilitates displacing solids from the annulus.
To help manage buoyancy, once the first lift was in place, the wet cast density of the cellular concrete on this Detroit Michigan annular space grouting project was reduced to 45lb/cuft CJFill-Standard. Reducing the wet cast density significantly reduces uplift, which allows taller lifts.
CJGeo used an onsite dry mix batch plant to generate the cellular concrete and pump it up to five hundred feet in the sewer line.
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Facing a similar challenge? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
