Prediction of Pavement Fatigue Life with Simulated Temperature Profile from Hourly Surface Temperatures

Publisher's full text
Åke Hermansson
Jesper Elsander

A typical model for predicting the fatigue life of an asphalt pavement involves mid-depth temperature and the elastic horizontal strains at the bottom of the asphalt layer. Strains are studied at the bottom of the asphalt layer as cracks are assumed to originate there. Pavement temperatures naturally experience daily fluctuations as a result of varying air temperature and solar radiation.

The amplitude of the oscillation decreases with depth and maximum temperature is reached later in the day at greater depth. During warming up, strain levels under loading increase as stiffness decreases, while the bottom of the asphalt layer is rather cold and thus sensitive to strains. At cooling down, strain decreases and the bottom layer is warm and withstands strains more easily. It is therefore proposed in this paper to use the temperature at the bottom of the asphalt layer instead of the mid-depth temperature when calculating fatigue damage. It is also proposed to use the complete temperature profile to improve the calculation of strain levels under loading. As the fatigue damage caused each hour will vary with temperature during the course of the day, it is also pointed out that the calculations might be improved by relating the distribution of traffic to the distribution of incremental fatigue damage.

A simulation model calculating the temperature profile and strain levels was developed and run for three different pavements with different thicknesses of asphalt layer. It was found that the distribution of incremental fatigue damage over a typical summer day could be completely different for different pavements.

MEET US


7
Dec

Shipping and the environment – research meets reality

Centre for Transport Studies (CTS) in co-operation with Ports of Stockholm invite you to the seminar Shipping and the environment – research meets reality.

LATEST NEWS


2017-10-16

ERPUG Forum

The five-year anniversary of European Road Profile Users' Group (ERPUG) Forum will take place at Ramboll head quarter, Copenhagen, Denmark October 19-20, 2017.


2017-09-29

Self-driving buses in Sweden next year?

A self-driving, fossil-free bus. This idea might become reality through a forthcoming collaborative project involving the Swedish National Road and Transport Research Institute (VTI), Linköping University and several other participants. The project group aim...


2017-09-29

New climate-proof solutions for hard surfaces in cities

High-density road infrastructure that emphasise maximum durability and minimum maintenance create inflexible systems, which put increased stress on urban trees and lead to increased risk for flooding. Over the past five years, the ‘Climate-proof solutions for...


2017-09-29

VTI is preparing for automated vehicles

Automation of traffic systems will lead to major changes. The European Union’s (EU) CoEXist research project began in June 2017 with the aim of preparing cities and road operators for the introduction of self-driving vehicles. The Swedish National Road and...


2017-07-05

Vehicle Driver Monitoring: sleepiness and cognitive load

To prevent road crashes it is important to understand driver related contributing factors, which have been suggested to be the critical reason in 94 per cent of crashes. The overall aim of the project Vehicle Driver Monitoring has been to advance the...


2017-06-29

Tomas Svensson new director-general

Tomas Svensson was today appointed Director-General of VTI. Tomas has been acting Director-General since January 2017.