Roller Compacted Concrete

Still Branch Reservoir

475

acre reservoir

950k

cubic yards embankment

42k

tons of aggregate drainage

Griffin, GA

475 acre reservoir; Earthen Dam “Category I Large Dam” – approx. 950,000 cy embankment; 100,000 cy of undercut; Outlet Structure; Drawdown Control piping; 65 ac wetlands mitigation; 1.5 mi paved roadway; 1.2 mi gravel roadway; 2,300 lf of 42” DIP & 1,900 lf of 30” DIP waterline; 735 lf of Pre-stressed Concrete Cylinder Pipe (PCCP); 540 ac of clearing; 110 ac of grassing; 9,000 tons of rip rap; 42,000 tons of aggregate drainage material. 

Stoney Creek Reservoir Dam Rehabilitation

Cat. 1

high hazard classification

2.9k

cubic yards reinforced concrete

20k

cubic yards excavation and backfill

Bedford, VA

Rehabilitation and reconstruction of the existing chute spillway including new sidewalls, parapet walls, cut-off walls, spillway crest, and chute slab overlay (approximately 2,900 CY of reinforced concrete); overtopping protection on the downstream side of the existing dam embankment consisting of 10,000 CY of roller-compacted concrete; sand blanket drain; stone trench drains including 2,500 LF of PVC perforated and solid pipe; 20,000 CY of excavation and backfill; Rip Rap channels; water line relocation; sheet piling; pressure injected grout; piezometers.

This dam is classified as Category I High Hazard. Control of water was handled by drawing down the existing lake, cofferdam installation at the crest of the existing spillway and localized pumping to mitigate ground water. A Rapidmix 600 pugmill mixer was used to mix the RCC. The RCC was transported via articulated dump trucks discharging into a Gomaco material transfer devise, which fed a stacker conveyor belt. A telescoping crane was used to receive the RCC and conveying it to the final placement location. 

Prichard Intermodal

21k

cubic yards of RCC

500

pound minimum of cementitious materials per cubic yard of RCC

Prichard, WV

The new Prichard Intermodal encompasses approximately 100 acre site in Prichard, WV. It is serviced by a Norfolk Southern railroad line. The site is bordered by the Big Sandy River on the west, which is also a state line between West Virginia and Kentucky. The facility offers industrial and warehousing space, a modern and efficient freight container service and improved access to international rail lines. The purpose of the project is to stimulate and support economic development within the region and provide and maintain connections to key regional and national transportation corridors.

Morgan Corp. Contributions

Morgan Corp. was the RCC paving subcontractor working with the prime contractor - Mountaineer Contractors. Morgan Corp. scope of work included mixing, transporting and placing more than 21,000 cubic yards of RCC paving. The entire RCC pavement is 18 inches thick, placed in two 9-inch lifts. Underneath the RCC layers, the pavement section consisted of a bituminous stabilized open graded drainage layer over an aggregate base course on top of the prepared subgrade.

The project specification required a minimum of 500 lbs. of cementitious materials per cubic yard of RCC. The specified compressive strength of molded cylinders was 5,000 psi at 28 days. Morgan Corp. designed the RCC mixture, which was verified by an independent testing laboratory. The RCC was mixed in a RapidMix 600 continuous pugmill mixer. A three bin blending hopper was used to convey the predetermined aggregate proportions to the mixer hopper. In addition to the plant primary cement silo, an auxiliary cement silo was used to augment the cement feed and maximize the RCC production rate in order to feed two paving trains simultaneously. Two Volvo high-density paving machines operating back-to-back placed the two lifts of RCC. The top lift was spread within 30 minutes of placing the bottom lift to ensure bonding at the lift interface. Cores obtained from the test section demonstrated 100% bonding at core locations.

Morgan Corp. optimization of the RCC mix design included several trial mixtures and selection of the best mix meeting (1) the required engineering properties and (2) the required performance during placing and rolling. The optimized gradation of the combined aggregates mixed with 500 lbs. of cement per cubic yard produced a compressive strength consistently exceeding the specified compressive strength by a wide margin.

Bridgestone Tire Plant

38.5k

square yards of RCC

7.5"

RCC surface layer

Aiken County, SC

This Bridgestone Tire project is a new manufacturing plant located in Trenton, Aiken County, SC. Construction of the facility started in 2011 and included 2 phases. The owner and the design team selected RCC as the pavement of choice for the access and haul roads in and around the plant. Placement of approximately half of the RCC pavements was included in each of the two construction phases.

Gresham Smith & Partners designed the pavement section, which consisted of a 6-inch aggregate base layer and a 7.5 inch RCC surface layer. The base layer was placed by others and served as a temporary construction road. The RCC for the first construction phase was also placed by others. Morgan Corp., working as a paving subcontractor to Kajima Design and Building Group, constructed the RCC for the second phase of the project. This phase of the work encompassed 38,500 square yards of RCC.

Morgan Corp. evaluated several sources of aggregates available nearby and chose materials different from what was used in Phase 1. An RCC mix design meeting the project requirements was selected based on laboratory testing and field performance during the first day of placement. The project was completed within the contract time and within budget. Owner, General Contractor, and the Architect/Engineer of record all expressed great satisfaction with the quality of the RCC placed by Morgan Corp. during the second phase of the project. When asked about the pavement, the project engineer stated, “The current RCC job being done by Morgan Corp. has shown Bridgestone what RCC could be.”

South Carolina Inland Port

57k

cubic yards of RCC paving

30k

cubic yards of cement-treated base

Greer, SC

The South Carolina Inland Port extends the Port of Charleston’s reach 212 miles inland and provides shippers with access to more than 95 million consumers within a one-day drive. The inland port boosts efficiency for international freight movements between the Port of Charleston and companies located across the Southeast.

Morgan Corp. work included mixing, transporting and placing more than 57,000 cubic yards of RCC paving and 30,000 cubic yards of cement-treated base. Approximately one half of the pavement area (97,000 square yards) was 13 inches thick placed in 2 lifts and the other half (85,500 square yards) was 9.5 inches thick placed in one lift. Work also included subgrade lime modification to render the silty subgrade manageable after frequent heavy rain events. RCC was mixed in a RapidMix 600 continuous pugmill mixer and placed with two Volvo high-density paving machines. A three bin blending hopper was used to convey the predetermined aggregate proportions to the mixer hopper. Cement was supplied from two silos feeding directly into the mixing chamber.

In addition to the RCC, CTB and lime modification operations, work included ancillary conventional concrete; railroad crossings, and underground utilities.

Value–Engineered Approach for Fast Construction and a Better Product at No Additional Cost

The subgrade soils at the site consisted of silty Clay and clayey Sand. The pavement design grade was 0.5 percent. The original designs consisted of (1) 14-inch RCC over 3-inch dense graded aggregate base for craneways and handling of loaded containers area and (2) 10-inch RCC over 3-inch dense graded base elsewhere. Based on Morgan Corp.’s extensive experience in grading and sitework, the design posed a major constructability problem because of the pavement design slope, expected rain fall in the area, and the soils encountered at the site. There was no chance for the 3-inch base layer to remain stable under construction traffic after rain events. To have a much better chance of completing the project with a reasonable time frame, Morgan Corp. designed new pavement sections of equal or higher structural capacity at no additional cost. These value engineered pavement sections included a 6-inch cement stabilized soil base layer instead of the 3-inch aggregate base. The RCC thicknesses were reduced from 14 and 10 inches to 13 and 9.5 inches, respectively. The soil base layer allowed placement of RCC within a few hours after rain events as compared to waiting days after rain events had the “as designed” base was installed.

Vogtle Electric Generation Station Units 3 and 4

670

acres of clearing, grubbing, grinding

45

acre parking lot

25%

cost savings in suggestions

60%

increase in structural capacity

Waynesboro, GA

Morgan Corp. provided a total site preparation and pavement package for construction of two new AP1000 Model, 1100Mw Nuclear Power Generating Units, covering over 1,000 acres of land disturbance. The project included laydown areas, craft and management parking areas, access roads, cooling towers, on-site batch plant area, and future switchyard.

Work performed included clearing, grubbing, and grinding of 670 acres; design, construction, and maintenance of a 50-acre multi-staged surface and subsurface dewatering system for two 90-foot-deep nuclear island excavations, as well as construction of 70 acres of roller-compacted concrete pavements over soil-cement pavement base layer.

Notable Details

RCC construction at Vogtle started in 2011 to build an approximately 45 acre parking lot. The original design called for a flexible pavement section consisting of 2 inches of hot mixed asphalt over 6 inches of graded aggregate base. Morgan Corp. proposed a value engineered RCC pavement section consisting of 4 inches of RCC over 6 inches of cement treated soil (CTS) base course. This value-engineered option was approved and used to build the parking lot pavement.

The RCC/CTS pavement section offered the following benefits:

  • 60% increase in structural capacity
  • 25% cost savings
  • 50% reduction in illumination power
  • Fast construction-sometimes opening the pavement to traffic one day after placement
  • Low maintenance and long service life
  • Many sustainability attributes by using in-situ soil for the base instead of mining, processing, and transporting aggregates that are not locally available

Building on the success of the RCC at the parking lot, all remaining parking and laydown areas, access roads, heavy-haul roads, etc. were built with RCC over a CTS base layer. RCC thicknesses used on this project for various loading and traffic conditions included 4, 6, 7, 10 and 18 inches.