Traffic - Introduction

Flexible pavements deform and fatigue under the repeated action of heavy vehicle traffic. Pavement design methods require accurate estimates of traffic loading. Traditionally, vehicle weight has been empirically related to decreased pavement serviceability through the Equivalent Single Axle Load (ESAL) calculated using the ‘fourth-power law’, as determined from the American Association of State Highway Officials (AASHO) Road Test (1958-1960) and codified in the AASHO Pavement Design Guide (Cebon 1999). ESALs implicitly incorporate a road damage...

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Moisture - Introduction

While asphalt layers are heavily affected by temperature, the resilient and permanent behaviour of granular materials are a function of moisture content. A model, therefore, has to be provided to simulate how moisture varies in the pavement and how this affects the performance of the granular layers. The moisture model presented hereafter is what is used in the ME-PDG, which seems to be most suitable thanks to its simplicity and flexibility. This approach takes into account the effect of moisture by multiplying the resilient modulus of the granular...

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Temperature - Introduction

As is well known, the behaviour of asphalt bound materials is extremely temperature dependent. Therefore, a model that estimates temperature profiles in the pavement structure at any particular moment of the pavement’s life is an important part of any predictive tool.The model that is initially being implemented in this software is based on the generally established Dempsey model. This procedure consists first in calculating an energy balance at the pavement’s surface at any particular time in order to estimate the amount of energy entering (or...

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Welcome

Predicting how a pavement will perform under certain levels of traffic and climatic conditions is extremely important for designers and planners, representing possibly one of the most complicated tasks and certainly the ultimate target of most of the research being done in the field of pavement engineering. In order to address this research topic, software is being developed to predict Long Term Pavement Performance (LTPPS) that will have the characteristics of being modular and open-source. This is a very large and ambitious project that involves...

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