Pavement performance modeling or pavement deterioration modeling is the study of pavement deterioration throughout its life-cycle. The health of pavement is assessed using different performance indicators. Some of the most well-known performance indicators are Pavement Condition Index (PCI), International Roughness Index (IRI) and ''

Present Serviceability Index The present serviceability index (PSI) is a pavement performance measure. Introduced by the American Association of State Highway and Transportation Officials (AASHTO), the PSI is one of the most widely used pavement performance indicators after pa ...

'' (PSI), but sometimes a single distress such as rutting or the extent of crack is used. Among the most frequently used methods for pavement performance modeling are mechanistic models, mechanistic-empirical models, survival curves and

Markov model In probability theory, a Markov model is a stochastic model used to model pseudo-randomly changing systems. It is assumed that future states depend only on the current state, not on the events that occurred before it (that is, it assumes the Mark ...

s. Recently,

machine learning Machine learning (ML) is a field of inquiry devoted to understanding and building methods that 'learn', that is, methods that leverage data to improve performance on some set of tasks. It is seen as a part of artificial intelligence. Machine ...

algorithms have been used for this purpose as well. Most studies on pavement performance modeling are based on

IRI IRI or I.R.I. refers to: Businesses and organizations * Iringa Airport, an airport in Tanzania serving Iringa and the surrounding Iringa Region by IATA airport code * India Rejuvenation Initiative, an Indian anti-corruption organization forme ...

History

The study of pavement performance goes back to the first half of 20th century. The first efforts in pavement performance modeling were based on mechanistic models. Later researchers also developed empirical models, which were not based on the structure of the pavement. Since the beginning of 1990s mechanistic-empirical (M-E) models have become popular. These models combined both mechanistic and empirical features via linear regression. In North America, AASHTO developed a guideline based on mechanistic-empirical methods. Development of such models required data. Therefore, in North America, organizations such as AASHTO and FHWA collected large amounts of data about pavement conditions. Examples of these databases, which are used for pavement design and performance measurement, are the

LTPP Long-Term Pavement Performance Program, known as LTPP, is a research project supported by Federal Highway Administration (FHWA) to collect and analyze pavement data in the United States and Canada. Currently, the LTPP acquires the largest road p ...

and

AASHO Road Test The AASHO Road Test was a series of experiments carried out by the American Association of State Highway and Transportation Officials (AASHTO), to determine how traffic contributed to the deterioration of highway pavements. Methodology Of ...

Causes of deterioration

The deterioration of roads is a complex phenomenon and is influenced by many factors. These factors can be classified into a few categories: design and construction, material type, environmental conditions, and managerial and operational factors.

Climate and environmental conditions

Among the most significant environmental factors are freeze-thaw cycles, maximum and minimum temperature and

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

. It is reported that on average roads in a wet climate with freeze cycles deteriorate up to two times more than roads in dry and no-freeze regions. So, roads exposed to larger number of freeze-thaw cycles and higher precipitation levels deteriorate faster. On the other hand, roads in dry and no freeze climates last longer. A very high temperature can be detrimental to asphalt pavement too and cause distresses such as

bleeding Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

. Considering this,

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

could pose a threat to the well-being of roads. Its impact, however, varies based on regions. While it can be highly detrimental to roads in a certain area it might alleviate the deterioration of roads in another area.

Traffic and operational conditions

The traffic count and the type of traffic are among the important operational attributes. Usually larger volumes of traffic and heavier vehicles such as trucks are correlated with faster pavement degradation. Also managerial approaches can have an important influence on deterioration patterns. Examples of the factors directly related to management are the type and frequency of maintenance or cleaning and deicing approaches in the winter. Using too much of deicing salt can exacerbate the corrosion problem especially in concrete pavement.

Type of pavement

The type of pavement is one of the most important factors affecting pavement deterioration. Generally concrete pavements are more durable in warmer climates, and asphalt pavements are more resilient against cold weather. The joints in concrete pavement is another source of issue. In a certain type of road (concrete, asphalt or gravel), the thickness of layers and type of materials used in base, sub-base and pavement layer matters. Sometimes these attributes are expressed via an aggregated measure called granular base equivalence (GBE).

References

{{Road types Pavements Pavement engineering Infrastructure asset management