Hamid Soleymani

Evaluation of the effects of Canadian climate conditions on the MEPDG predictions for flexible pavement performance

This study aims to investigate the quality of the recently developed Canadian climatic database and the effect of climatic factors on flexible pavement performance using the mechanistic-empirical pavement design guide (MEPDG). Two hundred and six Canadian climatic files were used to carry out the analysis. Freezing index and frost depth from the MEPDG were compared with the data available in Canadian databases. The sensitivity of pavement performance to climate conditions, predicted using the MEPDG, was also studied. The pavement performance predicted using the virtual weather station and existing weather station data was compared. From the pavement performance sensitivity study, it was found that the asphalt concrete, total pavement rutting and international roughness index show sensitivity to climate changes. It was also found that differences in the quality and duration of data for close-by stations can result in variation in the predicted performance. Overall, the study assists with facilitating the implementation of the MEPDG in Canada.

Developing a road performance index using a Bayesian belief network model

There is a high demand to develop and incorporate decision support tools, by the transportation sectors and other concerned agencies, to improve their infrastructure assets management under shrinking budgets and increasing demands. This paper develops a proof-of-concept Bayesian belief network (BBN) model to rank roads in a network system based on several key performance indicators (KPI) using a probabilistic framework. For a given road network, the proposed tool is capable of ranking or prioritizing the segment of roads for high level management objectives. To demonstrate the application of the proposed model, various scenarios are elaborated and discussed in detail. Finally, the sensitivity analysis is carried out to evaluate the effects of different KPIs.

Compression Behavior of Large-Sized Tire-Derived Aggregate for Embankment Application

Tire-derived aggregate (TDA) has been successfully used for highway embankment applications in the past. Previous applications mainly used small and medium tire sizes as TDA sources. There are no published test results in the literature regarding the compression behavior of TDA made solely from off-the-road tires (OTR). In this study, large-scale, one-dimensional compression tests are carried out to study the compression behavior of TDA from OTR as well as from passenger and light-truck tires (PLTT). Samples for the tests are prepared by varying the initial unit weights. The results show that there is a general trend of decreasing compressibility with increasing initial unit weight for both TDA sources. The compression test results are also used to compare compression behavior between the two TDA sources. It is found that the compression behavior of TDA from OTR and PLTT is more or less similar. Moreover, one-dimensional stress-strain regression equations were developed for TDA from OTR.

Field monitoring and comparison of thermal- and load-induced strains in asphalt pavement

The influence of pavement temperature variations on field thermal-induced strains has not been well studied. Measuring the thermal- and load-induced strains in field conditions will assist in developing realistic pavement performance fatigue models. A field investigation programme was developed at the University of Waterloo to quantify thermal-induced strains in typical Eastern Canadian climate conditions. The main objective of this field study was to measure and compare the amplitude of load- and thermal-induced strains over a 1-year monitoring period. Results indicated that the average monthly thermal-induced strains were higher than the load-induced strains by a 49 kN wheel load moving at 25 km/h. Although the frequency of thermal-induced strains is lower than the traffic loads, damage from thermal-induced strains could be more than load-induced strains due to higher amplitudes.

Evaluation of Asphalt Pavement Crack Sealing Performance Using Image Processing Technique

Crack sealing is a routine and necessary operation of pavement maintenance. Manual observation of road surfaces has been the most common method for evaluating road surface cracks around the world. However it is difficult to objectively and accurately assess the road cracks based on human visual perception. The ultimate objective of this study is to evaluate crack sealing performance on highways, in order to choose the best crack sealing practice in an automated manner. As a preliminary step, this paper discusses how to define crack sealing performance and propose a research methodology to quantify the level of road surface distress using video image processing.