Cell-Crete Assists in the Decommissioning of Underground Fuel Tanks

The Orange County Health Care Agency and the California Regional Water Quality Control Board required the closure of five underground fuel tanks at the former Marine Corps Air Station El Toro in Irvine, California. Originally constructed in 1953, these five Underground Storage Tanks (USTs) held a whopping 591,426 gallons of jet propulsion fuel and needed to be decommissioned by filling the tanks with an inert solid material in order to achieve regulatory closure concurrence.

Each of these USTs measured 88 ft wide and 13 ft high. Due to their size, and their unique placement underground, the Marine

Corps Air Station El Toro needed a solution that would be strong enough to reinforce the ground above, while providing little to no additional environmental impact.

To add to an already challenging job, there were only 10 days before the cutoff date to finish the project to avoid interruption to the breeding season of threatened species California gnatcatcher. Cell-Crete’s specialized Engineered Fill team rose to the challenge and finished installation in just six days. This enabled the contractor, Rore Inc., to finish the grading and hydroseeding of the area without incurring liquidated damages.

“We chose Cell-Crete because they are the only installer of cellular concrete that could complete the job to the incredibly tight schedule – notably, their ability to produce more than 3,000 cubic yards of low density cellular concrete per day,” said Steve Siefert of Rore Inc. “Because of their seamless installation in six days, we had the opportunity to complete our responsibilities on schedule.”

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Cell-Crete used cellular concrete – a material composed of water, cement and preformed foam – to fill the tanks. It’s blended on site with portable batch plants. Cell-Crete introduced the foam into the concrete slurry with an in-line blending system to produce air-filled cellular concrete. Once mixed with the concrete, the preformed foam creates a uniform matrix of air voids that are stable enough to withstand the hydration period. This technique leaves behind tiny pore spaces that are evenly dispersed within the concrete.

Cell-Crete set up two portable batch plants on site to expedite the tank filling process. These portable batch plants make for easy installation, a highly flowable texture and impressive compressive strength. It also complies with the strict environmental standards set by the Orange County Health Care Agency.

“Using preformed foam reduced the amount of trucks needed on site. We produced roughly 120 cubic yards of material with each truck load of cement (27 tons) – traditional CLSM or dirt would have required nine times the truck loads to achieve the same volume,” explained Diego Villegas, Engineered Fill Division Manager of Cell-Crete.

“At Cell-Crete, we know how important it is to get the job done right the first time, and on time. Filling the underground fuel tanks at the Marine Corps Air Station in El Toro is just one example of the work the Engineered Fill Department can do. We’re proud of what we did for Rore, Inc. and look forward to working with them again in the future,” he said.

With the tanks safely decommissioned, the city will turn the site into the Orange County Great Park.