Patching Runways Versus Attacking Dirt and Cement

The US has runway repair teams that can repair holes in two hours or less. They use truckloads of dirt and rocks and then cover with a 45 by 60-foot fiberglass mat.

Chinese suppliers sell fiberglass paving mats for 55 cents per square meter in lots of 10000 square meters.

T17 fast setting cement can set in 45 minutes and be ready for landings in about one hour.

Runway bombs have been standard for many decades. Each one has smaller bombs to make about 20 big holes.

Not a Maginot Line

The WW2 Maginot line had artillery with a few miles of range. China has missiles with hundreds and even many thousands of miles of range.

As shown in the Falklands War, modern missiles can sink surface ships.

China has thousands of mainland based missiles and many dozens of missiles on the islands.

The islands are up to 480 acres which is 100 times the area of an aircraft carrier. Holes can be patched in hours. Standard US bunker busters can penetrate 6 meters of concrete and 100 feet of dirt. Many dozens of bunker busters would be needed and the island missiles would be shooting back at carrier groups around the Philippines.

Repair Procedures: Airfield Damage Repair Part A: Filling the Crater

Crushed Stone Repair Procedures from Readymat. The rest of the article are the details of runway repair.

Clear debris from around the crater at least 6 meters (20 feet) in all directions to allow identification of the upheaved pavement surface. Identification and removal of all upheaval or damaged pavement is critical. It cannot be rolled down flush with the existing pavement and left. The upheaved pavement will eventually break up and create additional problems adjacent to the crater repair.

Perform profile measurement and visual inspection to identify and mark upheaval around the crater.

Remove upheaved pavement using an excavator with bucket or moil point attachment, and the front-end loader. The dozer may also be used, depending on the runway surface.

All debris material in excess of 304 millimeters (12 inches) must be removed or reduced in size. Breaking the pavement into smaller pieces will minimize the potential for voids and settling problems in the future.

Push unusable debris at least 9 meters (30 feet) off the Minimum Operating Strip (MOS) and pile no higher than 0.9 meter (3 feet).
Place backfill material into the crater in accordance with the repair procedure chosen. Note: If settling problems are anticipated, placement of membrane fabric between dissimilar backfill materials is recommended.

Fill and compact the crater with crushed stone material, placing it in lifts approximately 152 to 177 millimeters (6 to 7 inches) thick. For C-17 operations, limit the aggregate size to a maximum of 25 millimeters (1 inch) in the top 152 millimeters (6 inches) of the crushed stone repair. Overfill the crater by approximately 76 millimeters (3 inches) above the original pavement surface height. Compact each lift of crushed stone using a minimum of four passes of a single drum vibratory roller or two passes with a 10-ton vibratory roller. One pass of the roller means traveling across and back in the same lane.

If the crushed stone material is placed upon soft subgrade materials, it may be beneficial to separate the material using geomembrane fabric and place the crushed stone material in thicker lifts. In any case, the crushed stone should be compacted with a minimum of four passes of a single drum vibratory roller or two passes of a 10-ton vibratory roller per each 152 millimeters (6 inches) of thickness. A 457-millimeter (18-inch) crushed stone layer should receive a minimum of 12 passes with a single drum vibratory roller or six passes with a 10-ton vibratory roller prior to cut for the final grade.
Grade the compacted crushed stone to approximately 25 millimeters (1 inch) above the pavement surface.

Compact the crushed stone using two passes of a single drum vibratory roller or one pass with a 10-ton vibratory roller. The crushed stone layer should have a minimum 15 CBR to support C-130 and fighter jet operations.

Perform profile measurement. The repaired crater must not exceed the maximum RQC of ± 19 millimeters (± 0.75 inch). A repair outside this tolerance may still be useable, depending on its location, but will have a much shorter life before requiring additional maintenance to bring it back within this limitation.
The crushed stone repair is complete at this point.

Airfield Damage Repair Part B: Installing the FFM

The Readymat FFM is air-transportable, can be moved easily by vehicles, can be positioned at greater distances from airfield pavement surfaces, and can be stored indoors out of the elements.

A standard FFM weighs about 1360 kilograms (3,000 pounds) and consists of nine fiberglass panels, each 1.83 meters wide by 9.14 meters long by 12.7 millimeters thick (6 feet wide by 30 feet long by 0.30 inch thick nominally). Elastomer hinges 76.2 millimeters (3 inches) wide connect the panels. When folded, these mats are 1.83 meters wide by 9.14 meters long and 203 to 254 millimeters thick (6 feet wide by 30 feet long and 8 to10 inches thick). This repair system also includes joining panels and two support mat kits. The joining panels come in 7.32-meter and 9.14-meter (24-foot and 30-foot) lengths. One of each size is needed to connect two 9.14-meter by 16.46-meter (30-foot by 54 -foot) mats. The resulting 16.46-meter by 18.29-meter (54-foot by 60-foot) mat is the normal size suitable for most crater repairs. If larger FOD covers are required, additional mats may be spliced together. There are two types of support mat kits for the FFM. Mat Kit A contains all the necessary tools and hardware required to assemble, install, and maintain the system. Mat Kit B contains the anchor bolts required to attach the mat to the pavement surface.

SOURCES- Readymat, Rapid runway repair, wikipedia, US air force
Written by Brian Wang, Nextbigfuture.com