What is ASTM D5340?

Definition

ASTM D5340 is a test method that rates the surface condition of airport pavement with the Pavement Condition Index (PCI). Its full title is Standard Test Method for Airport Pavement Condition Index Surveys. An inspector looks at the pavement, records each distress, and the method turns the records into a PCI from 0 to 100. A PCI of 0 is a failed pavement and 100 is a new pavement.

What the name and the edition code mean

ASTM International publishes the standard. D5340 is its designation. The number after the dash shows the year of original adoption or of the last revision, so D5340-24 is the 2024 edition. ASTM lists D5340-24 as the active edition and shows earlier editions such as D5340-23, D5340-20 and D5340-12.

What it covers

The method covers asphalt-surfaced pavement, including porous friction courses, and jointed concrete pavement, plain or reinforced. The US Army Corps of Engineers developed the PCI for airport pavement with funding from the US Air Force. The FAA and the US Naval Facilities Engineering Command adopted it.

ASTM sells the standard. ASTM D6433 is the matching method for roads and parking lots. See ASTM D6433 . The FAA publishes the PAVER distress manuals, which hold the distress definitions, with its advisory circular on the airport pavement management program (AC 150/5380-7B).

The PCI rating scale

The 1998 edition of the standard gives a verbal rating for each PCI range in Fig. 1. The scale has these bands:

The FAA AC 150/5380-7B shows PCI rating scales only as examples. Check the scale in the edition and the contract that you use.

How a survey works

The inspector separates the pavement by use into runways, taxiways and aprons. These are the branches. The inspector divides each area into sections with the same design, construction history, traffic and condition. The inspector then divides each section into sample units:

• Asphalt: 5,000 square feet, plus or minus 2,000 square feet (450 plus or minus 180 square metres).
• Concrete: 20 slabs, plus or minus 8 slabs. If the joint spacing is more than 25 ft (8 m), the inspector divides each slab into imaginary slabs of 25 ft or less.

The inspector marks each sample unit so that others can find it again. Paint marks along the edge and sketches that tie to pavement features are acceptable. The standard does not recommend nails or other possible sources of foreign object debris. The inspector must be able to find the same unit again. This lets others check the data and see the change over time.

Sampling

The 1998 edition lets the user survey all sample units in a section, enough units for a 95 percent confidence level, or fewer. All units are usually too costly for routine management. They suit project analysis, where they help to estimate the quantities of work.

The minimum number of sample units, n, comes from this formula:

n = N s² / ((e² / 4)(N - 1) + s²)

• N is the total number of sample units in the section.
• e is the acceptable error in the section PCI. It is commonly 5 PCI points.
• s is the standard deviation of the PCI between sample units. In the first inspection it is assumed to be 10 for asphalt and 15 for concrete. Later inspections use the value from the previous one.

The inspector rounds n up. For example, take a section of 40 asphalt sample units with e = 5 and s = 10. Then n = 4,000 / 343.75 = 11.6, and the inspector surveys 12 units.

The units are spaced evenly with systematic random sampling. The interval is i = N / n rounded down, and the first unit is chosen at random. In the example, i is 40 / 12 = 3.33, so the interval is 3. An additional sample unit is one that holds a non-representative distress, such as a utility cut. The user selects these units, and they are counted apart from the random sample.

Inspection

The inspector walks over each sample unit. On asphalt, the inspector sketches the unit and measures its size with a hand odometer wheel. The inspector then measures the quantity of each distress type at each severity level, to 0.1 ft (30 mm). On concrete, the inspector walks over each slab and records the distresses and severity levels. The inspector counts the slabs that hold each type and severity.

Traffic is a hazard because inspectors walk on the pavement. The standard says that the airport operational staff must approve and coordinate the inspection. Aircraft noise can also be a hazard, so hearing protection must be available during airside inspections.

Calculation

The calculation has these steps for asphalt:

1. Divide the quantity of each distress and severity by the area of the sample unit and multiply by 100. The result is the percent density.
2. Read a deduct value for each distress and severity from the standard’s curves.
3. Combine the deduct values into a maximum corrected deduct value. If none or only one deduct value is above 5, the total is used. Otherwise a stepwise procedure applies. It limits the number of deduct values to m, where m = 1 + (9/95)(100 - HDV) and m is not above 10. HDV is the highest deduct value.
4. Subtract the maximum corrected deduct value from 100. The result is the PCI of the sample unit.

For concrete, the density is the share of slabs with a distress and severity. Divide the number of those slabs by the number of slabs in the sample unit and multiply by 100. The rest is the same.

The standard’s asphalt example (Fig. 4 and Fig. 6) shows the steps. The highest deduct value is 27.0, so m is 7.92. The inspector keeps the seven largest deduct values and 0.92 of the eighth, which is 1.8 from 2.0. The total is 92.5 and q is 4. The inspector repeats the step with the smallest deduct value above 5 set to 5, until q is 1. The largest corrected deduct value is 57.5. The PCI is 100 - 57.5 = 42.5, and Fig. 6 gives the rating fair.

The PCI of the section is the average of the sample unit PCIs. It is a weighted average if the inspector added extra sample units. The section report lists the location, size, number of sample units, units inspected, PCIs, average PCI and the condition rating.

Distress types

The FAA PAVER manuals list 17 asphalt distress types (codes 41 to 57) and 16 concrete distress types (codes 61 to 76). They implement STANAG 7181. The 1998 edition of the standard lists 16 and 15. The count depends on the edition. Jet blast erosion (46) and oil spillage (49) have no severity levels. The inspector records the area in square feet or square metres.

• Asphalt, codes 41 to 49: alligator cracking, bleeding, block cracking, corrugation, depression, jet blast erosion, joint reflection cracking, longitudinal and transverse cracking, oil spillage.
• Asphalt, codes 50 to 57: patching and utility cut patch, polished aggregate, raveling, rutting, shoving, slippage cracking, swell, weathering.
• Concrete, codes 61 to 68: blowup, corner break, cracks, durability cracking, joint seal damage, small patching, large patching, popouts.
• Concrete, codes 69 to 76: pumping, scaling, settlement or faulting, shattered slab, shrinkage cracks, joint spalling, corner spalling, alkali-silica reaction (ASR).

The asphalt manual measures most distress types in square feet (square metres). It measures joint reflection cracking and longitudinal and transverse cracking in linear feet (metres). On concrete, the inspector counts slabs. If one area of alligator cracking has several severity levels, the inspector measures each level apart where that is easy. Where it is not easy, the inspector rates the whole area at the highest severity present.

Many severity levels depend on foreign object debris (FOD) potential. A joint reflection crack is low severity with little or no FOD potential. It is high severity when it is severely spalled, with definite FOD potential. If an inspector records high severity ASR on a slab, the inspector records no other distress on that slab.

What the PCI does not measure

The PCI cannot measure structural capacity. It gives no direct measurement of skid resistance or roughness. It does not replace direct measurement of roughness, structural capacity, texture or friction. AC 150/5320-6G names AC 150/5380-9 for roughness and AC 150/5320-12 for friction.

FAA AC 150/5320-6G says that PCI is a visual rating of the surface. Further investigation must find the cause of a distress.

Accuracy in the 1998 edition

The 1998 edition says that no precision estimate came from statistically designed tests. A note gives expectations. Inspectors should identify the distress type correctly 95 percent of the time. Linear measurements should agree within 10 percent on remeasurement, and area measurements within 20 percent.

Use by the FAA

FAA AC 150/5380-7B describes the airport pavement management program. A federally obligated airport must make a detailed pavement inspection at least once a year. A PCI survey to ASTM D5340 allows the interval to be three years. The airport must keep records of the distress types, their locations and the maintenance that it scheduled or did. The FAA PAVEAIR web program is one pavement management tool. The AC is mandatory for projects that AIP or PFC funds pay for.

FAA AC 150/5320-6G links the PCI to the type of work. A pavement with a PCI above 70 is a candidate for maintenance. One with a PCI from 55 to 70 is a candidate for rehabilitation. One with a PCI below 55 may be a candidate for reconstruction. The AC says these limits are relative. A project can justify another strategy on either side of a limit.

Drone surveys

The 1998 edition assumes that inspectors walk on the pavement. Its apparatus list includes a hand odometer wheel, a straightedge or string line and a ruler. It does not mention drones or aerial imagery. Whether a drone survey meets a contract is a question for that contract and the edition that it names.

TarmacView plans survey flights and captures the photos of airfield pavement today. Crack detection and the D5340 rating are in development and offered as early access. See what ASTM D5340 asks of a drone survey .