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Riverton Utah Commercial Void Fill and Soil Stabilization

In early February of 2018, a major water line break caused significant voiding be- neath the floor slab of a large commercial retail warehouse in Riverton UT. The pressure of the water was so great, in addition to causing large voids beneath the floor, it actually cracked the slab, and push water through the control joints in the concrete, flooding portions of the store. Scott Davis with Kleinfelder Engineering contacted CST concerning the damage, looking for an in situ solution to fill the voids. Soil testing performed after the water line break revealed that the soil compaction beneath the floor was good, but the voided areas would need to be filled. The solution would need to be performed without having to move permanently installed shelving units and merchandise and be completed without a lengthy closure for the business.

CST partnered with Tradesmithe Property Management and Kleinfelder Engineering to design an in situ repair plan to fill the voids and provide continuous , uniform subgrade support. The solution needed to provide a minimum of 6,000 PSF compressive strength of the soil and maintain dimensional stability for the life of the structure. CST’s in situ soil stabilization technologies employs a high density, expansive structural polymer injected through small holes directly through the floor slab and into the subgrade soils. The polymer, in it’s liquid state travels along finding voided areas and expands to fill and re-compact the compromised soil. Injection holes are very small and are filled with grout once repairs are complete. Once cured, the polymer reaches a much higher compressive strength that easily exceeded what was required for this project.

Once all voided areas were identified and marked, CST installed ESP material and completed void fill on a total area of 26,000 SQ FT.  All repair work was completed in 3 nights, allowing the business to stay open during the day.

Due to the highly advanced injection techniques and equipment, permanent shelving units and merchandise did not have to be moved in order to make the repairs.

The repair process efficiently and effectively restored compaction to the sub- grade soils and provided a solid solution to extend and preserve the useful life of the floor slab and structure.

CST’s polymer injection process does not require excavation and is environmentally friendly while providing fast, clean, permanent results.

  • Locate all voided areas and complete repairs without moving permanently installed shelving features and
    merchandise.
  • Permanently installed shelving, fix- tures, and appliances could not be moved during the repair.
  • No excavation required.
  • Environmentally friendly.
  • Little to no disruption to business.
  • Extends the useful life of existing slabs and structures.
Culvert Annular Void Fill
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Utah DOT Culvert Annular Void Fill

Objective of this project was to fill annulus between culvert and surrounding embankment. The outer pipe was rusted out at the bottom and water was leaking in between the two pipes and coming out bottom of joint. Goal was to seal leaks in an outer pipe, surrounding smaller pipe and fill voids.

Critical elements of this project were dealing with the rusted out bottom of the outer surrounding pipe. Large amounts of water needed to be pushed out and fill resultant voids to assure pipe support and stability.

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Salt Lake City Industrial Road Restoration – UT

Patching, Diamond Grinding and Joint Resealing

Located close to downtown Salt Lake City, Industrial Road at California Avenue needed some well deserved repair. Industrial Road is a critical concrete pavement thoroughfare for industrial traffic and heavy duty trucking in the area as it is located adjacent to a major truck stop and trucker fuel depot. The majority of the concrete pavement was structurally sound but, due in part to sub-grade softening caused by surface water intrusion through the joints, the pavement exhibited differential settlement between the slabs measuring up to 1.5-inches. The combination of constant heavy truck traffic and the presence of water in the sub-grade facilitated continued erosion beneath the slabs.

Although the owner, the Salt Lake City Corporation, considered replacing all concrete slabs. They opted instead to preserve the existing concrete. After all, only 10 percent of the slabs showed cracking. The methods chosen for repair were soil foundation stabilization, slabjacking, slab replacement, stitch-in-time crack repair, dowel bar retrofit (DBR), diamond grinding and joint resealing. A total of 326 dowels were retrofitted on the 1,461 square-yard project. A series of 5/8 inch holes were drilled through the slabs to facilitate the injection of high density expansive polymers into the sub-grade soil to a depth of 3.5 feet. With the deep injection process complete, the same polymers were then injected at the slab/sub-grade interface through the same 5/8-inch holes to fill fissures and voids as well as to lift each concrete slab to match the elevation of adjacent slabs. This process minimized the differential settlement between the slabs. Additional lifting was then employed beneath the slabs to create a 1.5 percent drainage slope from the crown of the road to the curb to facilitate better drainage and safety.

This design engineer decided to test an innovative new crack stitching procedure utilizing polyurethane material and fiberglass panels. The CST Stitch-In-Time process was selected and used beneath five slabs that contained minor cracks. Following the slab stabilization and lifting operations, the Stitch-in-Time process required the placement of ½ inch fiberglass panels (stitches) within saw cuts made perpendicular to the slab crack. The cuts were then filled with clean pea gravel and an acrylic bonding material was poured into each cut. Four stitches were placed in each candidate slab.

Following the stabilization, lifting and stitching operations, the retrofit dowel bars were installed in the slabs, severely cracked slabs were removed and new concrete was placed in the necessary areas. Once the concrete was fully cured, the entire area was diamond ground to remove remaining surface defects, increase smoothness and provide a safe, high friction wearing surface. The joints between the slabs were then cleaned and resealed to prevent the intrusion of water and incompressible materials. As a final step, a sealing compound was applied to the concrete surface to provide additional protection.
Another challenge was slab cutting at the joints prior to the lifting process. The summer heat caused slab expansion, which can bind the saw blades and restrict a slab’s upward movement. To prevent this occurrence, a chisel-shaped device was inserted into the saw cut adjacent to the trapped blade and pressure was applied to spread the cut sufficiently to allow the blade to be extracted.

The project was scheduled for 90 days but was completed in a mere 62 days and was under budget. As a result of this successful project, the owner has chosen to use concrete pavement preservation on future projects within the city. The combination of using high density expansive polymers in conjunction with other concrete pavement preservation techniques including dowel bar retrofit and diamond grinding should extend the life of this pavement for approximately 15-20 years.
According to Mike Kendell of SLC Engineering, “Ride quality was greatly improved and Salt Lake City is satisfied with the results.”

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Cereal Plant Rail Car Soil Stabilization – Ogden, UT

The Problem

Undermining and settlement of sub grade soils of railway track and load out canopy area of Cereal Food Processors, Inc. plant, Ogden Utah.

Situation

Concrete Stabilization Technologies, Inc. Field Consultant, Jonathon George was contacted by Scott Roberts of Cereal Foods, Inc. concerning settlement issues around the load out area for rail cars at the cereal processing plant located in Ogden, UT.

Settlement occurred due to a water main leak which had undermined sub grade soils around approximately 120 linear feet of railway track. The area of rail canopy is supported by five pillars. The middle of the five pillars showed the greatest amount of settlement of 1 to ½ inches while the other pillars in both directions had also experienced settlement, but to a lesser degree.

Facts for Consideration

The settled area of the Cereal Food Processor plant is in area used to load rail cars with grain. The area is used on a daily basis with empty rail cars rolling into the canopy area, being loaded with grain, and then moving the heavy load to other areas of the plant for production. This being a vital part of the plant’s production sequence, taking the tracks out of service for an extended period of time, would not only slow production, but affect the plant’s profit margin. Due to the non-invasive process and rapid curing time of CST geopolymers, the track was only out of service for a couple of hours.

Soil test results revealed compromised soil in the settled areas at a depth of three to four feet below the surface grade. No settlement of the tracks themselves had occurred, however, tests performed beneath the tracks did reveal soft soils. As a preventative measure against future settlement in the track area, it was recommended to the owner to treat soils beneath the rail ballast as well.

Solution

Initial soil tests were made in the areas of the canopy pillars and track sub grade. Results of the testing indicated very soft soil three to four feet down into the sub grade area. Penetrometer testing also revealed soft soil beneath the track area as well.

CST’s deep injection method was used to stabilize the affected areas. Repair work began at the center of the east track. 5/8” holes were drilled and probes placed into the sub grade soils. Geopolymer was injected through the probes into the soil on five feet center and four feet below the top of the concrete/asphalt overlay. The purpose of the injections between the tracks was to fill any voids, stabilizing the weak soil, and interlocking the sub grade with the ballast, preventing future settlement.

Once the track area was completed, injections were then made beneath the spread footer of each of the five pillars to stabilize soil and prevent settlement. The two pillars with the most severe settlement were addressed first. Injections were made at depths of one, three, and five feet below the bottom of each spread footer. For the remaining three pillars, injection was made at one and three feet below the bottom of each spread footer. Close monitoring of surface movement at the surface was made during injection, and movement was detected from all injections.

Results

  • 120 Linear Feet of track area sub grade soils successfully stabilized
  • CST successfully stabilized the five supporting canopy pillars in the rail car load out area
  • CST successfully stabilized 120 linear feet of weak soil beneath the rail track area.

Benefits

Time Savings:  Repairs were completed in one day. Track was useable immediately following injection of sub grade soils.
Cost Savings:  Conservatively reduced repair costs by 50% (versus reconstruction).
Longevity:  Repairs permanently stabilized the source of the settlement – weak soils, mitigating future settlement and damage to canopy as well as rail track line through area.