30/06/2026
Rigid concrete pavements develop distinct distress patterns such as corner breaks, joint spalling, faulting and pumping. This article explains the causes of these distresses, how they affect PCI ratings and why structural evaluation with HWD is often needed to understand the condition beneath the slab.
Airport rigid pavements (Portland Cement Concrete – PCC) are subjected to heavy aircraft loading, environmental effects, temperature variations, and water infiltration. These factors lead to deterioration that can affect both operational safety and structural capacity. The most common distresses identified during airport PCI surveys (ASTM D5340) are corner breaks, longitudinal/transverse/diagonal cracks, shattered slabs, joint and corner spalling, joint seal damage, pumping, faulting (differential settlement), D-cracking, scaling and popouts.
| PCI Range | Condition | Typical Distresses | Likely Cause | Recommended Action |
| 85–100 | Excellent | Minor joint seal deterioration, isolated low-severity cracks | Normal aging and environmental exposure | Routine inspections, joint resealing, preventive maintenance |
| 70–85 | Good | Early spalling, isolated cracks, minor faulting | Thermal movements and localized load effects | Crack sealing, joint repair, localized patching |
| 55–70 | Fair | Moderate cracking, spalling, joint deterioration, localized pumping | Water infiltration and repeated aircraft loading | Partial-depth repairs, slab stabilization and drainage improvements |
| 40–55 | Poor | Frequent corner breaks, significant spalling, increasing faulting | Loss of support beneath slabs and structural deterioration | Full-depth slab repairs and major rehabilitation |
| 25–40 | Very Poor | Multiple corner breaks, pumping, severe faulting and intersecting cracks | Progressive structural failure of slab and foundation | Extensive slab replacement or rehabilitation |
| 0–25 | Failed | Shattered slabs and widespread structural distress | Complete loss of pavement structural integrity | Reconstruction |
Why PCI Surveys Are Useful
The Pavement Condition Index (PCI) is a standardized rating from 0 to 100 based on the type, severity and extent of visible pavement distresses. It provides an objective measure of the pavement’s surface condition and helps airport authorities prioritize maintenance and rehabilitation activities. Regular PCI surveys allow deterioration trends to be monitored over time, making it possible to intervene before major failures develop. PCI is therefore an essential component of an Airport Pavement Management System (APMS).
However, PCI primarily reflects surface condition. A pavement can sometimes have an acceptable PCI while underlying structural problems are already developing. For this reason, PCI should not be used alone.
Why HWD Surveys Are Useful
The Heavy Weight Deflectometer (HWD) evaluates the structural condition of airport pavements by applying loads that simulate aircraft wheel loads and measuring the resulting deflection response. HWD testing provides information on slab support conditions, load transfer efficiency across joints, structural capacity, remaining life and potential foundation problems that cannot be detected from visual inspections alone.
While PCI answers the question“What surface distresses are visible?”, HWD answers“Is the pavement structure still capable of carrying future aircraft traffic?”. Combining PCI and HWD surveys enables airport owners to distinguish between functional problems (cracking, spalling, roughness) and structural deficiencies (loss of support, reduced load transfer and insufficient capacity). This integrated approach leads to more reliable maintenance planning and more cost-effective rehabilitation decisions.
In summary, PCI surveys provide a measure of pavement condition and deterioration, while HWD surveys assess structural health. Together they form the foundation of a sound airport pavement management strategy, allowing timely interventions that maximize pavement life and minimize rehabilitation costs.
Surface Distress Doesn’t Tell the Whole Story
PCI surveys help identify visible deterioration, while Dynatest Heavy Weight Deflectometer (HWD) provides insight into structural condition, support quality and pavement capacity. Together they help airport owners make more informed maintenance and rehabilitation decisions.
FAQ Rigid pavement distress
A corner break is a crack that intersects two joints of a concrete slab, creating a triangular piece at the slab corner. It is typically caused by loss of support beneath the slab corner combined with repeated heavy loading. Corner breaks are often considered a sign of underlying foundation problems.
A shattered slab is a concrete slab that has fractured into four or more pieces because of intersecting cracks. It is generally considered a form of structural failure and often requires full-depth slab replacement.
Joint spalling occurs when the edges of a concrete slab near a joint begin to crack, chip or break away. Common causes include incompressible materials in the joint, poor concrete quality and repeated traffic loading. On airports, severe spalling can also create Foreign Object Debris (FOD) risks.
Faulting is a difference in elevation between adjacent concrete slabs. It is commonly associated with pumping, loss of base support and differential settlement. Faulting can increase pavement roughness and impact loading.
Pumping occurs when water and fine particles are forced out through joints and cracks under repeated traffic loading. It is often an indication that the pavement foundation is deteriorating and can lead to faulting, settlement and structural distress
Rigid pavement distresses are typically evaluated by identifying the distress type, severity and extent. These observations are used as inputs for Pavement Condition Index (PCI) calculations according to ASTM standards for roads and airports.
The Pavement Condition Index (PCI) is a numerical rating that reflects pavement condition based on observed surface distresses and their severity. PCI is commonly used to support maintenance planning and pavement management decisions.
Not always. Surface distresses show visible deterioration, but many rigid pavement problems originate below the slab in the base or subgrade layers. Hidden loss of support may not be visible during a surface inspection.
PCI surveys evaluate visible pavement condition, while Heavy Weight Deflectometer (HWD) testing evaluates structural behavior and support conditions beneath the slab. Combining both methods provides a more complete understanding of pavement health and rehabilitation needs.
An HWD measures pavement deflection under a controlled load. The resulting data can be used to assess structural capacity, slab support conditions and other foundation-related issues that cannot be identified through visual inspections alone.