Light evaluation keeps heavy mission flying

  • Published
  • By 374th Civil Engineer Squadron
YOKOTA AIR BASE, Japan --  An airfield pavement evaluation team from the Air Force Civil Engineer Center recently conducted an airfield test and evaluation July 8 - 20, 2013, at Yokota Air Base, Japan. The team travels to various Air Force bases throughout the year to take core samples and conduct non-destructive impact and friction testing and visual analysis.

These evaluations determine the allowable gross load of the runway and inform base organizations which sections of the airfield need repairs, or those that may need improvement in the future. The results also determine where to park aircraft and which taxiways should be used.

"The evaluation team is critical to the operation of an efficient airfield," said 1st Lt. Jackson Goss, 374th Civil Engineer Squadron construction management chief. "Without the APE team's evaluation, the airfield could fall into disrepair, thus impacting the airlift mission. They perform tests on the sub-pavement that cannot be seen with the naked eye, so even though a piece of airfield may look good, there may be faults lying underneath the pavement."

A special truck is used to extract the asphalt and concrete cylinder cores, each about six inches in diameter and roughly 14 inches long depending on pavement thickness, according to construction management chief. The cores are crushed to determine their strength.

The non-destructive impact testing device is used to measure the strength of the pavement and the underlying materials. It works by lifting a 1,100-pound weight package two feet, and dropping it on the pavement. The weight package simulates a 50,000-pound, fully-loaded aircraft landing on the surface, which measures the strength of the top-level concrete and the layers of soil beneath it.

Finally, the team conducted a visual analysis by checking pavement for distresses such as cracks and spalls in the runway, ramp and taxi areas. Depending on the analysis results, the team may test more thoroughly in one area to further identify problems.

Airmen from the 374 CES operations flight, known as "Dirt Boys", supported the evaluation team by filling in the core holes with new concrete, keeping the airfield in top condition. This prevented the holes from exposure to rain which could enter the soil layer under the pavement and weaken that layer, according to Goss.

"The Dirt Boys did great staying right with the team for the entirety of the coring process and ensured that once the runway closure was over, the airfield was immediately operational," said Tech. Sgt. Frank Uecker, 374 CES pavements and equipment noncommissioned officer in charge.

Goss said the Dirt Boys here are constantly performing crack and joint seals to prevent water from entering the pavement.

"So far in 2013, the Dirt Boys have sealed more than 12,000 feet of cracks and seams," he added.

A repair to Yokota's delta ramp was made in response to the last evaluation here, removing and replacing the asphalt pavement, Goss said. The evaluation found the ramp to have thermally expanded leading to cracks and degrades in adjoining asphalt pavement.

Although this year's official reports have not been finalized, initial reports indicate the airfield is in excellent condition.