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Annular Space Grouting Projects

By applying unique solutions to increase the safety and longevity of our environment.

Texas Annular Space Grouting

The Job

This Texas annular space grouting project is located in Lockhart, Texas. It is a 42″ treated water pipeline for the Alliance Regional Water Authority.

The Challenge

The annular space grouting for this tunnel was specified for cellular concrete. The minimum allowable compressive strength was 300psi at 28 days, when tested according to ASTM C495. The 42″ treated water pipeline was installed inside of a 60″ casing pipe.

The tunnel was approximately 460LF, and crossed under a frontage road and Texas State Highway 130, about 20 miles south of Austin.

The Solution

Due to the Texas cement market being extremely strained, CJGeo proposed using onsite dry batch generation to make the cellular grout onsite. This has a few advantages over using ready mix (wet batch generation):

  • purchasing cement directly from a cement plant bypasses ready mix plant’s cement allocation limits
  • bulk material doesn’t go bad onsite

CJGeo used a relatively high water:cement ratio to account for temperatures of 105 degrees during the placement and generation. This helped to ensure that material did not prematurely set during placement, and allowed CJGeo to generate and place all of the 40lb/cuft CJFill-Standard cellular grout material in just three hours.

Confirmation of fill for this Texas annular space grouting project was material venting from the 12 o’clock vent on the far end of the tunnel. Pumping pressures were less than 15psi for the duration of the grouting process.

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Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Microtunnel Contact Grouting

The Job

This microtunnel contact grouting project is located in Clarksville, Tennessee. It is part of a new water intake structure along the Cumberland River to improve the reliability of the city’s municipal water source.

The Challenge

Based on the overcut of about an inch, and length of the 450 foot long tunnel, the contact grouting volume was approximately 50CY. In order to efficiently place the grout against the roughly 40′ of head from the river that that the tunnel terminates in, high volume, high quality mixing was required.

The tunneling contractor reached out to CJGeo to use onsite colloidal batching to generate grout quickly, safely, and without the risks of using ready mix.

The Solution

CJGeo proposed using a 0.55 water : cement ratio slurry generated onsite with colloidal mixing for the contact grout. While there were nearby ready mix plants that could have supplied the job, mixing neat grouts in transit mixer trucks typically does not uniformly wet out the cement. This can make it very difficult to pump, and typically results in highly variable mixes. Because the grout is the same as the cement slurry used for making CJFill cellular concrete, CJGeo used a cellular concrete batch plant with the foam generator turned off.

CJGeo batched and placed 50CY of slurry over about 2.5 hours to complete the microtunnel contact grouting. Placement of the grout was through 2″ ports, and the grout displaced both the lubricating bentonite slurry, and significant amounts of water. Due to the exceptionally high mobility of colloidally mixed neat cement grout, CJGeo’s crew was able to grout the entire length of the tunnel from two ports located just in from the launch shaft.

Grout communication was confirmed through lubricating ports, visual confirmation from the casing pipe drying due to heat of hydration, and divers in the river witnessing grout at the tremied bulkhead.

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Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Nashville Annular Space Grouting

The Job

This Nashville annular space grouting project is located at Nashville’s Central WWTP, which is undergoing extensive improvements to provide service to a growing population.

The Challenge

As part of an upgrade, 400LF of 66″ pipe was slip lined. Once the carrier pipe was selected, the space around its 57.1″ OD needed to be filled.

The Solution

CJGeo proposed using CJFill-ST at 45lb/cuft for this Nashville annular space grouting project. CJFill-ST is batched onsite directly from bulk cement, eliminating supply chain issues with ready mix.

Because the selected CJFill-ST only weigh 45lb/cuft, buoyancy control of the new carrier is simple. By filling it with water, it won’t float during grouting. This allowed CJGeo to grout the entire annulus in a single lift. Single lift grouting significantly reduces the likelihood of partial fills, fouled injection tubing, or trapped voids.

A CJGeo crew placed the 87CY of CJFill-ST in less than an hour to perform this Nashville annular space grouting project. CJFill-ST can be made two ways; wet batch or dry batch. With wet batch, a ready mix truck brings the base slurry to the site, and the foam is either added to the truck, or injected downstream of a pump. For dry batch generation, which was used here, a mobile batch plant mixes the cement and water onsite. The mixing quality using dry batch is significantly better than wet batch.

This project had a relatively high compressive strength requirement due to new foundation installation adjacent to the slip lined pipe. With cellular concrete, there are two ways to increase compressive strength–increase the cement content by increasing the density, or increasing the quality of the mix. Since annular space grouting projects are very sensitive to carrier pipe buoyancy control, increasing mix quality is a better option than increasing density. CJGeo’s three mobile batch plants all use high shear colloidal mixing. Colloidally generated material can have 28 day strengths up to two times ready mix batched material at the same density & cement content.

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Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Parsippany Annular Space Grouting

The Job

This Parsippany annular space grouting project is part of a microtunneled installation of 48″ sanitary line in two runs under an interstate. Each tunnel is 60″ diameter, one was 725LF, the other 530LF. They shared a shaft. The project’s goal is to replace an aging stretch of large diameter gravity sewer that runs parallel to the interstate.

The Challenge

The owner specified a grouted annular space for the tunnels. The long pumping distance and relatively tight annulus drove the need for a highly mobile, lightweight grout.

The Solution

CJGeo placed 270CY of 35lb/cuft CJFill-ST (36ksf unconfined compressive strength) cellular grout to fill the annulus on both tunnels. Because the shared shaft wasn’t easily accessible, grouting was performed from each end towards the shared shaft over two back to back days.

CJGeo used onsite dry batching to generate the cellular grout for this Parsippany annular space grouting project. Dry batch generation uses bulk cement, eliminating risks associated with the ready mix supply chain. Cellular grout made using the dry batch process is also much higher quality, which allows CJGeo to get higher strengths with lower densities. This lowers pumping pressure, buoyancy, and costs.

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Facing a similar challenge? Give us a shout or shoot us a text.

Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Niles Avenue Annular Space Grouting

The Job

Atlanta Watershed Management’s Niles Avenue Sewer Improvements project involved approximately 2500LF of microtunneling to install a new 18″ sewer main.

The Challenge

A 72″ microtunnel was chosen, which required approximately 1200CY of annular space grouting. Operations were challenged by the pandemic hitting in the middle of the project.

The Solution

CJGeo proposed 30lb/cuft CJFill-UL cellular grout for the annular space grout. This allowed the contractor to avoid mechanical buoyancy control during grouting operations during single lift grouting.

Over two mobilizations, CJGeo generated the cellular grout onsite and placed it via shafts which were up to 40 feet deep.

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Facing a similar challenge? Give us a shout or shoot us a text.

Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Garden State Parkway grouting

The Job

As part of ongoing large diameter culvert rehabilitations and replacements, four new bored stormwater crossings and the original culvert they replaced needed to be grouted. The tunnels ranged from 120″ down to 74″, for a total of 312CY, and the abandonment required 405CY.

The Challenge

Grout needed to meet the minimum strength requirements of the owner, and ideally needed to be light enough to facilitate single lift annular space grouting.

The Solution

CJGeo’s preconstruction team worked with the general contractor to design a grouting program which facilitated single lift abandonment of the original culvert, and single lift grouting of the four various annular space runs. CJGeo utilized onsite dry batching to generate 30lb/cuft CJFill cellular concrete.

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Facing a similar challenge? Give us a shout or shoot us a text.

Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Union County Annular Space Grouting

The Job

Due to a rapidly increasing population, Union County, North Carolina installed a new raw water intake. It required a nearly 11 mile long raw water line to supply a water treatment plant.

The Challenge

There were dozens of open cut road crossings along the alignment. 17 crossings were bored, and require annular space grouting per NCDOT requirements. Given the length of the project, there weren’t any ready mix providers who could cover this entire annular space grouting in North Carolina project.

The Solution

CJGeo has multiple NCDOT approved mix designs, for CJFill-UL. CJGeo sourced material from two different ready mix providers. Each annular space on all crossings was grouted per NCDOT requirements.

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Facing a similar challenge? Give us a shout or shoot us a text.

Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Neuse River Annular Grouting

The Job

The City of Raleigh’s Neuse River East Parallel Interceptor project involves the installation of miles of large diameter gravity sewer. Two road crossings required 120″ tunnels for installation of the 96″ HOBAS pipe.

The Challenge

While neither tunnel was very long, due to the 10′ diameter tunnels, grouting needed to be performed in two lifts. This allowed buoyancy control of the HOBAS carrier pipes to be maintained with partial water filling, and eliminated the need to perform hold down blocking during the carrier pipe installation.

The Solution

CJGeo proposed an NCDOT approved cellular grout mix due to passage through an NCDOT right of way, and then grouted the two tunnels each in two lifts. Fill was confirmed with uniform grout vented out the 12 o’clock vent position at the far end of each tunnel.

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Facing a similar challenge? Give us a shout or shoot us a text.

Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Dairy Branch Annular Space Grouting

The Job

Charlotte Water’s Dairy Branch Tributary Sewer project is an approximately $30mm capacity improvement project to address increased density.

The Challenge

As part of the project, a 430LF tunnel ranging from 58″ bore to a 4×4 arch was mined. The carrier pipe was 36″ ductile iron, and required annular space grouting using a mix which wouldn’t float the carrier pipe, and would be able to entirely fill the tunnel at low pressure.

The Solution

CJGeo proposed an NCDOT approved cellular grout mix due to passage through an NCDOT right of way, and then placed the 275CY of grout in a single lift over two hours at approximately 5psi of placement pressure.

Speak With An Expert

Facing a similar challenge? Give us a shout or shoot us a text.

Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683

Bay Park Annular Space Grouting

The Job

The Bay Park Conveyance Project is using a combination of microtunneling and slip-lining to redirect treated effluent discharge from Western Bay to an existing ocean outfall several miles away.

The Challenge

Approximately 7 miles of the discharge pipe is being sliplined into an existing 72″ riveted iron pipe running underneath the Sunset Highway. Access pits are between 700LF & 3000LF apart, requiring annular space grouting placements ranging from 200CY to 850CY.

Due to maintenance of traffic concerns, all grouting must be performed at night, and there is nowhere to stage materials onsite.

The Solution

Working with the design and construction teams, CJGeo designed a 30lb/cuft, 150psi at 28 day compressive strength cellular grout for the annular space grouting. By using dry batch mixing onsite, CJGeo is able to achieve the compressive strength required, and place the distances required in the very short nightly placement windows.

To address material logistics, each night’s cement consumption is staged locally during the day, and then shuttled in to each placement location during the pours.

Speak With An Expert

Facing a similar challenge? Give us a shout or shoot us a text.

Virginia to MaineNorth Carolina to FloridaEverywhere Else
James CorbinAndrew TaliaferroMartha Moore
d: 804-442-7371d: 804-471-3061d: 804-404-2683
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