In the last decades, a new type of distress has been observed more and more frequently on asphalt pavements. This distress, ascribable to fatigue failure, has been named top-down cracking (TDC) because it consists in longitudinal cracks that initiate on the pavement surface and then propagate downwards. A series of surveys recently carried out on Italian motorways highlighted that TDC can affect up to 20%–30% of the slow traffic lane. Therefore, in order to achieve a better understanding of such distress, this paper reviews causes, models and experimental tools and highlights future challenges for TDC. The literature review indicates that TDC can evolve on the pavement surface in three stages (i.e., single crack, sister cracks, alligator cracking) and, below a certain depth, the cracks can form angles of 20°–40° with respect to the vertical plane. Even though multiple factors contribute to TDC development, thick pavements are more likely to fail due to TDC induced by tire-pavement contact stresses, especially in the presence of open-graded friction courses (OGFCs). Moreover, in literature there are several TDC models based on mechanics (e.g., fracture mechanics or continuum damage mechanics) which allow a rigorous study of crack initiation and propagation. Future challenges include the identification of a reliable and feasible test method, among those proposed in literature, to study the TDC performance of asphalt mixtures and the implementation of TDC in pavement management systems (PMSs) through the definition of criteria for TDC recognition in the field as well as for the rehabilitation depth evaluation. Finally, more research is needed for open-graded asphalt mixtures, which present critical drawbacks in terms of TDC.

A review of top-down cracking in asphalt pavements: Causes, models, experimental tools and future challenges

A method to evaluate the segregation of compacted asphalt pavement by processing the images of paved asphalt mixture

Prediction of rapid chloride penetration resistance of metakaolin based high strength concrete using light GBM and XGBoost models by incorporating SHAP analysis

Distress types are significant for asphalt pavement maintenance decision, and relationships among them can greatly influence the decision outcomes. In this study, to analyze the relationships among different distress types from a statistical point of view, 282 asphalt pavements with semirigid base structures in 23 regions of China were surveyed to identify 12 distress types, which were subsequently investigated by association rule mining. Results show that the distress types can be categorized into independent distress types (IDDTs), dependent distress types (DDTs), and rutting secondary distress types (RSDTs) based on the relationships. The relationships among IDDTs are the strongest, and those between IDDTs and DDTs, between rutting and RSDTs, and among depression, pumping, and raveling are also strong, while the others are weak. The weak relationships should be ignored, while the strong ones should be considered to reduce cost and guarantee accuracy of maintenance decision. The IDDTs are the most important distress types, so preventing them from occurring or maintaining them immediately can greatly preserve good performance of asphalt pavements. To help analyze the relationships, a distress-type system was established and verified. In conclusion, this work provides new insights to understand distress types.

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Research on Relationships among Different Distress Types of Asphalt Pavements with Semi-Rigid Bases in China Using Association Rule Mining: A Statistical Point of View

Asphalt pavement paving segregation detection method using more efficiency and quality texture features extract algorithm

Segregation of asphalt mixtures indicates an artificially altered aggregate gradation, which consists of excessive coarse aggregates and insufficient fine aggregates that may result in premature failures and eventually reduce the pavement service life. Since segregation may cause a significant change in aggregate structure of asphalt mixtures, segregated mixtures may exhibit an increased potential for rutting among all other distresses. However, the effect of segregation on rutting potential has not been clearly identified. In this study, the effect of segregation on change in aggregate gradation (particularly for coarse aggregate structure) that may negatively affect the rutting potential of asphalt mixtures was evaluated. The Dominant Aggregate Size Range (DASR) gradation model and the DASR porosity parameter found to be well correlated with rutting performance of asphalt mixtures were employed for evaluation. A total of four field sections exhibiting different severities of segregation were selected and evaluated. Results of laboratory testing and DASR analysis indicated that segregated mixtures caused a significant shift in aggregate gradation, especially for coarse aggregate portion of the mixture gradation, which may result in significantly increased the potential for rutting. The results obtained from laboratory tests and the DASR approach were then compared and verified with those of actual filed rutting performance.

Evaluation of the effect of segregation on coarse aggregate structure and rutting potential of asphalt mixtures using Dominant Aggregate Size Range (DASR) approach

This study was mainly focused on evaluating the structural benefits of a prime coat application that may positively affect pavement performance based on the pavement response measurements using Accelerated Pavement Testing (APT). Two full-scale field test sections were built using different interlayer conditions between Asphalt Concrete (AC) and base layer including prime coat and no treatment for evaluation. Strain gauges and pressure cells were instrumented for each test section to conduct pavement response measurements. Results indicate that the application of prime coat was able to significantly reduce stress and strain responses at critical locations of pavement structure by providing a structural bond between layers that result in enhanced pavement performance compared to pavement with no treatment. In addition, based on the results of relative performance estimated, it was found that pavement structures with prime coat application potentially lead to improved performance including fatigue cracking, top-down cracking and subgrade rutting compared to pavements with no treatment and pavement damage seems to be accelerated for pavement system without prime coat application. Also, the full-scale field tests conducted using APT were determined to be capable of effectively capturing the structural effect of prime coat application on change in pavement critical responses for enhanced performance of asphalt pavements with more realistic and reliable results.

Evaluation of structural benefits of prime coat application for flexible pavements using Accelerated Pavement Testing (APT)

This study primarily focuses on evaluating the falling weight deflectometer (FWD) time history data for use in relative cracking assessment of asphalt pavements. Eight field project sections with a similar pavement structure were selected for evaluation; they include sections with and without the evidence of cracks. FWD tests were conducted for all selected field sections at a similar temperature to obtain load–deflection time history data. The results of the FWD-dissipated energy were further compared with the results of the energy ratio (ER), which is a well-known performance-based fracture property previously introduced for the cracking performance evaluation of asphalt mixtures. Pavement structures with the existence of cracks showed significantly greater FWD-dissipated energy and maximum deflection indicating a relatively higher rate of deterioration and/or damage for the pavement systems. Additionally, a proportional relationship identified between rate of change in normalized ER and FWD-dissipated energy confirmed that the FWD time history data was able to effectively differentiate pavement structures with and without the existence of cracks. Comparative results between the FWD-dissipated energy and the ER further support the validity of application of FWD-dissipated energy and the maximum deflection as a reliable material and/or pavement structural response indicator that can be used for cracking performance evaluation of asphalt pavements.

Bongsuk Park

Papers

Evaluation of the effect of segregation on coarse aggregate structure and rutting potential of asphalt mixtures using Dominant Aggregate Size Range (DASR) approach

Evaluation of structural benefits of prime coat application for flexible pavements using Accelerated Pavement Testing (APT)

Application of Falling Weight Deflectometer (FWD) Data and Energy Ratio (ER) Approach for Cracking Performance Evaluation of Asphalt Pavements

Precast prestressed concrete pavement (PPCP): Effect of thermal gradient on curling deflection and stress

Evaluation of asphalt pavement interface conditions for enhanced bond performance.