Traffic Load Effects Research Articles

Dynamic analysis of the train-bridge system considering the non-linear behaviour of the track-deck interface

This article presents an efficient computational methodology for solving the train-track-bridge interaction problem, including track irregularities and considering the non-linear behaviour of the track-deck interface. One of the novelties of the work is the proposal of a specific finite element used to model the track-deck interface, based on an assembly of a friction contact element and a non-linear spring, which is generally not used in non-linear dynamic problems. This element automatically performs changes in the longitudinal resistance of the track, according to the positions of the traffic loads, and takes into account the loading history. The dynamic analyses are performed based on an iterative methodology implemented in AIVE software, which takes advantage of the advanced modeling tools of Abaqus software controlled on Matlab. This software ensures flexibility in the selection of the methods for solving the dynamic problem and allows the incorporation of non-linearities in the vehicle and bridge models, including their interfaces. A parametric study was performed in order to demonstrate the importance of including the non-linear behaviour at the track-deck interface in the evaluation of the dynamic responses of the bridge and vehicle subsystems, under different scenarios of deck temperature, horizontal stiffness of the supports and deck cross-sections. The results show that the responses of the track-deck interface are more influenced by the effects of temperature variations than by the effects of vertical traffic loads, particularly for medium and large span bridges. Significant plastic incursions were detected at the track-deck interface under realistic temperature scenarios, particularly on the side of the mobile support. Under vertical traffic loads, the extension of the regions with plastic behaviour proved to be sensitive to variations in the horizontal stiffness of the support. Additionally, another important achievement of this study was the evaluation of the plastic incursions at the track-deck interface for different bridges typologies. Relevant incursions were detected for medium and large span bridges, where the extension of these regions can reach 25–55% of the bridge span, otherwise, for short span bridges, practically no significant plasticized regions were identified. Non-linear incursions on the track-deck interface cause an overall reduction of the track-bridge stiffness, leading to an increase of the vertical movements of the bridge, and, inherently, of the vehicle’s dynamic responses. The evaluation of the extension of the ballast plastic regions for the different analysis scenarios, which is still a topic shortly addressed in the bibliography, will be particularly useful for upgrading the existing methods for assessment of the dynamic behavior of railway bridges.

Evaluation of dynamic characteristics of silt in Yellow River Flood Field after freeze-thaw cycles

Frothing is a main disease of highways in Yellow River Flood Field, due to the loss of dynamic strength of roadbed soils under the couple effects of temperature, salt, and vehicle traffic load. This is strongly linked to the dynamic characteristics of silt in this region. To analyze these couple effects on the dynamic characteristics of silt, a series of tests (i.e., freeze-thaw cycling tests, vibration triaxial tests and ultrasonic wave velocity tests) were conducted and two kinds of silt (i.e., salt-free and 3%-salt silt) were designed. The results indicate that the dynamic shear strength and dynamic modulus decrease with increasing freeze-thaw cycles, while the damping ratio simultaneously increases. Furthermore, compared to salt-free silt, the decrement of dynamic shear strength and dynamic modulus of silt with 3% salt is more significant, but the damping ratio of 3%-salt silt is larger. In ultrasonic wave velocity tests, ultrasonic wave velocity of frozen soil specimens decreases as the number of freeze-thaw cycles increases. Based on the results of ultrasonic wave velocity tests, a preliminary model is proposed to evaluate damage of silt through field measurement ultrasonic data. The study could provide a theoretical basis for the treatment of silty soil highway.

Fatigue Stress Analysis of Key Nodes in Cable-girder Anchorage Zone of Long-span Cable-stayed Bridge

Under the long-term effect of traffic load, the cable-girder anchorage zone of the cable-stayed bridge will be continuously subjected to fatigue stress, so the real-time stress state of this part is one of the important factors affecting the safe operation of the long-span cable-stayed bridge. In the present paper, finite element software was used to analyze the stress state of the key nodes of a typical steel anchor box of a long-span cable-stayed bridge, and based on the European, American and Chinese standards, the fatigue strength of the key nodes was evaluated according to the stress results. The evaluation results show that the fatigue strength of the cable-girder anchorage zone can meet the requirements of various codes and can continue to operate safely.

A systematic approach to estimating traffic load effects on bridges using weigh‐in‐motion data

AbstractIn contrast to the Swiss load model used for new bridge structures (SIA 261), which has roots in a Europe‐wide weigh‐in‐motion (WIM) study and considers the full design life of new structures, the model for existing structures (SIA 269) from 2005 is derived from load effects produced by traffic measured by country‐specific WIM observations and considers a reduced return period.With growing concerns regarding the scarcity of resources, efforts should be made to ensure safety by increasing the knowledge of loads and load‐carrying mechanisms, rather than through overdesign. This paper presents the methodology employed to use WIM data for generating maximum expected load effects on bridges and thus give engineers a tool with which bridge load effects can be accurately derived from real traffic. A re‐evaluation using the methodology outlined here began this year. It is planned to use the results of this for the next revision of the Swiss National Annexes to the Eurocodes and SIA 269.

Weigh-in-Motion-Based Fatigue Damage Assessment

Weigh-in-motion (WIM) data provide an excellent opportunity to study the effects of actual traffic loads on bridges. Here procedures are presented for using WIM data to quantify the fatigue damage accumulated in steel bridges. These procedures allow comparisons of the impacts of truck traffic on various routes beyond simple comparisons of the numbers and gross vehicles weights of trucks in the traffic streams. The fatigue damage accumulation procedures are demonstrated using WIM traffic data collected in the state of Alabama. The results of the analysis show that approximately 20% of trucks are overloaded, that is, permit loads and illegal loads, and those trucks create more than 50% of the total damage based on the combined data from all the WIM locations in the state. The contribution of overloaded trucks to the total fatigue damage varies so that their contribution is less significant along some routes. A typical steel bridge with bottom flange coverplates was evaluated using the WIM data from 1 year for a heavily traveled route. This analysis shows that the fatigue life of the bridge was consumed at an annual rate consistent with a mean life of 100 years. These procedures have applications in planning weight limit enforcement, budgeting, and maintenance, and they have the potential for future use in planning inspection intervals.

Parameter Analysis of Wall Thickness of Cured-in-Place Pipe Linings for Semistructured Rehabilitation of Concrete Drainage Pipe

Frequent accidents caused by underground pipeline damage are a widespread societal concern. Trenchless rehabilitation methods, particularly cured-in-place pipe (CIPP) lining, are increasingly used for pipeline repair with great success. Existing research is mainly concerned with practical improvements in rehabilitation and evaluating the performance of rehabilitation. In this study, the model of corroded buried concrete pipeline that had been rehabilitated with CIPP was established using numerical methods, and the Mesh-based parallel-Code Coupling Interface (MpCCI) was used to investigate multifield coupling effects of soil pressure, traffic load, and fluid-structure interactions. Moreover, the influences of corrosion depth, corrosion width, traffic load, cover depth, and water quantity on CIPP wall thickness were compared and analyzed. The result shows that maximum principal stress and vertical displacement of pipeline markedly decreased after CIPP rehabilitation, and thus the new CIPP can carry loads in a deteriorated pipe. Stress and displacement of the composite pipe liner were positively correlated with corrosion depth and negatively correlated with corrosion width. Increase in traffic load rapidly increases von Mises stress of CIPP, and increase in cover depth rapidly increases maximum principal stress of pipeline. Water flow has little effect on the pipe liner, and flow capacity increases slightly after CIPP rehabilitation. CIPP wall thickness was positively correlated with corrosion depth, traffic load, cover depth, and water quantity and negatively correlated with corrosion width.

Effect of uneven multilane truck loading of multigirder bridges on component reliability

AbstractPremature failure of bridge components, caused by heavy trucks, is a major safety concern. Current studies well characterize the integral structural behavior of bridges under realistic stochastic traffic loading. However, there is little research on the differences in traffic loads over multiple lanes (a worldwide traffic phenomenon) and the resulting difference in the bridge component performance. In this paper, several sets of unidirectional two‐lane, three‐lane, and four‐lane weigh‐in‐motion data are available for the statistical evaluation of typical multigirder concrete bridges with structural types of slab beams, T‐shape beams, and box beams. Lane‐occurrence behavior, volume, load, and weight correlation of trucks are determined to have the largest impact on failure probability. Extreme and equivalent load effects (LEs) under multilane truck loading are calculated to assess bearing capacity and fatigue performance. The greater the number of lanes, the larger the discrepancies of truck volume and weight by lane. The differences in the traffic LE and reliability indices for each girder in the same bridge increase with greater number of lanes, shorter span, and weaker lateral girder connection. These results provide the background of designing or maintaining the bridges to pursue uniform target reliability of each girder component under realistic multilane truck loading.

Laboratory Investigation of an Alternative Permeability Indicator to Determine Optimal Maintenance Timing for Open-Graded Friction Course

Open-graded friction course (OGFC) is a low impact development practice that provides a better pavement drainage solution and safer driving conditions. However, there exists a gap in understanding how internal pores in OGFC mix affect hydraulic conductivity, particularly when OGFC suffers the most rutting damage under the effects of high temperature and heavy traffic loading. There is also a lack of research on determining the optimal maintenance timing for an OGFC pavement. This study aims at characterizing the relationship of volumetric and permeability properties for OGFC slab specimens and quantifying permeability deterioration over time using a developed precipitation simulator and permeability measuring device and rutting test. Seven test temperatures (40, 45, 50, 55, 60, 65, and 70°C) were considered in the rutting test. The effect of clogging material size on permeability was also evaluated. The test results suggested that interconnected air void was lower than total air void, and higher rutting temperature resulted in reduced interconnected air void. The clogging experiment suggested that 0.3–0.6 mm material caused the most clogging while 0.075–0.15 mm material caused the least clogging. Based on this study, it is recommended to use a field measured rut depth as an alternative permeability indicator for determining optimal maintenance timing for an OGFC pavement using the correlation established between permeability and rut depth. A case study of OGFC pavement demonstrated that when the field measured rut depth reached 4.5 mm or higher, timely maintenance is needed.

Developing Life-Extending Benefit Curves for Asphalt Pavements with Preservation Treatments

Over time, new pavements deteriorate due to the effect of traffic loads and the environment. If appropriate treatments are applied during the early stages of deterioration, it is possible to improve pavement conditions and extend pavement life without increasing expenditures. The National Center for Asphalt Technology (NCAT) has partnered with the Minnesota DOT’s Road Research Facility (MnROAD) to conduct a pavement preservation study that evaluates the life-extending benefit of a variety of preservation treatments, ranging from crack sealing to thin overlays. The objective of this research partnership is to develop performance curves for the treated pavements under different conditions (climate, traffic and initial condition of the pavement). In this study, full-scale test sections were treated first in a southern location (Alabama) on roadways subjected to both low and high traffic levels, starting in the summer of 2012. The experiment was extended in 2016 to include test sections in a northern location (Minnesota) to evaluate the effect of cold climate, also for low and high traffic levels. Throughout this time, cracking, roughness, rutting and macrotexture data were collected biweekly to evaluate pavement performance. The observed trends in the first years of the experiment indicate that there is not a significant variation in roughness or rutting over time, and that performance is mainly affected by the amount of cracking. Furthermore, the condition of the pavement at the time of treatment significantly affects the performance of the treated pavements, as pavements that are treated while still in good condition tend to remain in that category for a longer time. The results also demonstrate the effectiveness of applying pavement preservation treatments versus the “do nothing” scenario. After 4.8 years, the amount of cracking observed is less than the amount expected if the sections were left untreated, even for sections treated with applications that are not designed to address cracking. The results shown in this paper should be considered preliminary and used with caution. Data collection efforts continue in both southern and northern locations with the objective of determining the life-extending benefits of pavement preservation treatments as a function of initial condition, climate and traffic.

Multi-input performance prediction models for flexible pavements using LTPP database

Pavement performance prediction is a primary concern for pavement researchers and practitioners. The impact of climatic conditions and traffic characteristics on pavement performance is indisputable. The main objective of this study is to investigate the combined effect of both climate and traffic loading on pavement performance. Multi-input performance prediction models in terms of the well-known Pavement Condition Index (PCI) are proposed. The Long-Term Pavement Performance (LTPP) database is used for the models development and validation. Data from 89 LTPP sections including 617 observations from the Specific Pavement Studies (SPS-1) with no maintenance activities are collected. These data cover the four climatic zones (wet, wet freeze, dry, and dry freeze) in the USA, different pavement structures, and different levels of traffic loading. Based on these data, PCI prediction models are developed using two modeling approaches: multiple linear regression analysis and artificial neural networks (ANNs). The proposed models predict the PCI as a function of climatic factors, namely average annual temperature, standard deviation of monthly temperature, precipitation, wind speed, freezing index, total pavement thickness, and weighted plasticity index. Additionally, traffic loading, expressed in terms of the classical equivalent single-axle loads, is considered. The regression model yielded a coefficient of determination (R2) value of 0.80, whereas the ANNs model results in a relatively higher R2 value of 0.88. The proposed models are not only simple and accurate; they also have the potentials of being adopted in countries experiencing similar climatic conditions and traffic loading.

Investigation of multi-lane factor models for bridge traffic load effects using multiple lane traffic data

Multi-lane factor (MLF) is a crucial component of the traffic load model in design specifications for bridges. Due to the significant changes in highway freight transportation over the past two decades, it is urgent to propose precise MLFs for bridge assessment under onerous traffic loading. This study reviews the underpinning approaches of existing MLF models and uses numerical examples and site-specific weigh-in-motion data to investigate the performance of these approaches. First of all, three MLF underpinning approaches described in the literature, i.e., the multi-presence truck weights approach, the multi-presence truck load effects approach, and the coincident lane load effects approach, are illustrated and discussed. Then, numerical examples of multi-lane bridge traffic load effects without lane load disparity are used to compare the MLFs calibrated by the three approaches. Finally, realistic weigh-in-motion data that have a strong lane load disparity are employed to calibrate MLFs by these approaches, and the MLFs are compared with those in bridge design codes. Results show that the three approaches have large deviations on MLFs calculation based on the same traffic data and studied bridges. In general, the coincident lane load effects approach is flexible for MLF calibration of traffic data with and without lane load disparity. However, its calculation procedure is relatively complicated, especially when the number of traffic lanes is large. The multi-presence truck load effects approach gives comparable results of traffic data without lane load disparity but overestimates MLFs when there is lane disparity of traffic loads over multiple lanes. The multi-presence truck weights approach needs to be improved for traffic data with and without lane load disparity otherwise generates large deviations. The selection and improvement of the three approaches are further discussed. This work highlights the importance of MLF approaches to consider the lane disparity of traffic loads over multiple lanes in practical engineering.

A Spatiotemporal Model for Peak AoI in Uplink IoT Networks: Time Versus Event-Triggered Traffic

Timely message delivery is a key enabler for Internet of Things (IoT) and cyber–physical systems to support a wide range of context-dependent applications. Conventional time-related metrics (e.g., delay and jitter) fail to characterize the timeliness of the system update. Age of Information (AoI) is a time-evolving metric that accounts for the packet interarrival and waiting times to assess the freshness of information. In the foreseen large-scale IoT networks, mutual interference imposes a delicate relation between traffic generation patterns and transmission delays. To this end, we provide a spatiotemporal framework that captures the peak AoI (PAoI) for the large-scale IoT uplink network under time-triggered (TT) and event-triggered (ET) traffic. Tools from the stochastic geometry and queueing theory are utilized to account for the macroscopic and microscopic network scales. Simulations are conducted to validate the proposed mathematical framework and assess the effect of traffic load on the PAoI. The results unveil a counter-intuitive superiority of the ET traffic over the TT in terms of PAoI, which is due to the involved temporal interference correlations. Insights regarding the network stability frontiers and the location-dependent performance are presented. Key design recommendations regarding the traffic load and decoding thresholds are highlighted.

Strain-Based Performance Warning Method for Bridge Main Girders under Variable Operating Conditions

This paper proposes a strain-based performance warning method for bridge main girder monitoring using the long-term data obtained for varying load conditions, i.e., the variations in temperature, wind, and traffic load. Because the temperature field variation of the main girder is easy to measure, a correlation model between temperature and strain of the main girder was first established through a novel representative temperature, namely, the canonically correlated temperature. Based on this model, temperature effects on the main girder strain can be accurately estimated and eliminated. However, the influence of wind and traffic load on the main girder strain was difficult to quantify. Thus, principal component analysis was then employed to model the main girder strain after eliminating temperature effects, and the first two principal components were extracted to represent the effects of wind and traffic load, which could subsequently be eliminated. The remaining principal components were then used to reconstruct the model errors, which were minimally influenced by the varying operating conditions. After this analysis, two warning indexes (i.e., the Euclidean distance and the Mahalanobis distance) were defined for the model errors and the remaining principal components to detect potential performance degradations. In addition, a location index was deduced based on contribution analysis to indicate where the performance degradation occurs. Finally, an engineering application to a cable-stayed bridge was carried out to verify the capability and validity of the proposed method.

A gradient boosting approach to understanding airport runway and taxiway pavement deterioration

ABSTRACT Understanding airfield pavement deterioration is essential for airport asset management to ensure safe and efficient airport operations. This paper employs Gradient Boosting Machine (GBM) – a machine learning method – to investigate the contributions of a variety of influencing factors to runway and taxiway pavement deterioration at Chicago O’Hare International Airport. By adopting a systematic procedure consisting of model training, validation, and testing, two separate GBM models are developed to estimate Pavement Condition Index (PCI) of runways and taxiways. The models account for various input variables that are believed to affect pavement deterioration, including pavement age and material, maintenance and rehabilitation history, weather conditions, and air traffic loading effects. The developed GBM models are shown to outperform other methods (including linear regression, nonlinear regression, artificial neural networks, and random forest) in terms of model goodness-of-fit for both runway and taxiway pavements. The GBM modelling results are subsequently used to interpret the influence of individual input variables as well as their interactions on PCI, using relative importance and partial dependence plots. With promising results, the study demonstrates the use of an approach that was not previously considered in infrastructure management and can help airport agencies enhance the ability to understand airport asset performance.

Numerical and Experimental Investigation of the Effect of Traffic Load on the Mechanical Characteristics of HDPE Double-Wall Corrugated Pipe

The high-density polyethylene (HDPE) double-wall corrugated pipe, which is a kind of flexible pipe, is widely used in municipal drainage networks. The characteristics of the surrounding soil and pipe bed, pipe cover depth, backfill compaction, type of pavement and pavement design, and traffic loads are some of the major factors that affect the stress and deformation of pipes. In this study, the ABAQUS 3D finite element model was used to analyze the influence of backfill compactness, traffic loads, diameter, and hoop stiffness on the mechanical characteristic of an HDPE pipe under traffic loads. A series of full-scale tests were carried out to verify the validity of the simulation results. For the conditions tested, the results showed the following: (1) the Von-Mises stress of the pipe was mainly determined by the earth pressure at the crown, and the stress caused by backfill compaction increased significantly but had a short duration and limited impact on the pipe; (2) traffic load alone had little influence on the mechanical behavior of the pipe: while under the action of the loose backfill in contact with the pipe, the pipes were more sensitive to the traffic load response; (3) the fluctuations in the Von-Mises stress of the pipe mainly depended on the magnitude and speed of the traffic load; (4) for pipes with a small diameter, non-compacted backfill easily caused stress concentration in the pipe, while the degree of backfill compaction had almost the same effect on the distribution of stress for pipes with different hoop stiffness.

Numerical Prediction of the Bridge Subsidence Induced by Longwall Mining: A Case Study of the Majiagou Bridge

The Majiagou Bridge comprising four sub-bridges is adjacent to the Weiqiang coal mine, Yulin City, Shaanxi Province, China. The mining of the longwall panel No. 1307 may damage the Majiagou Bridge. In this study, we predicted the mining-induced bridge movements using the finite element method (FEM) to examine whether the progressive mining of the longwall panel will pose a negative impact on the Majiagou Bridge. We reconstructed detailed three-dimensional models of the four sub-bridges by considering the superstructures and substructures. The input mechanical properties of the strata are estimated by calibrating with available field monitoring data. Effect of traffic load on the bridge subsidence is also accounted. The numerical predictions are: (1) after the panel No. 1307 is mined, the maximum vertical and horizontal displacements of the four bridges are 61.2 mm and 84.8 mm respectively, which occur on the sub-bridge D that is closest to the longwall panel, (2) traffic load has much less pronounced effect on the Majiagou Bridge than that due to mining, and (3) the maximum tilt and horizontal strain of the sub-bridges are 3.42e−5 m/m and 2.19e−5 m/m, which occur on sub-bridge B and sub-bridge A, respectively. In terms of tilt, the Majiagou Bridge is safe whereas it is to be damaged in terms of horizontal movement that is more critical in causing structural damage. Therefore, we suggest that a reasonably wider protective coal pillar should be set if the panel No. 1307 is to be mined, to ensure the safety of the Majiagou Bridge.

An energy efficient distributed queuing random access (EE-DQRA) MAC protocol for wireless body sensor networks

In wireless sensor networks, a significant amount of energy is consumed by the sensor nodes during data packet transmission and reception. An IEEE 802.15.4 MAC protocol is not able to completely satisfy all the requirements of wireless body sensor networks (BSNs) in a healthcare environment. Hence there is a demand for the design of a new scalable and energy saving MAC protocols. In this paper the challenging healthcare requirements are considered and based upon these requirements, an energy efficient distributed queuing random access (EE-DQRA) MAC protocol is proposed for BSN scenarios which utilizes the concept of distributed queuing for enhanced radio channel utilization. The theoretical analysis of energy efficient EE-DQRA MAC protocol is being carried out systematically considering the limitations of IEEE 802.15.4 and DQ-MAC protocol. Further, EE-DQRA performance is validated with IEEE 802.15.4 system parameters using computer simulations. The effect of relative traffic load and payload length on the energy consumption, delay and throughput are also analyzed. The simulation results shows that the proposed EE-DQRA MAC with M/M/K queuing has better energy performance than the existing DQ-MAC and IEEE 802.15.4 MAC in BSN scenarios due to collisionless transmission in the data transmission queuing (DTQ) module while keeping the control packet overhead smaller in collision resolution queuing (CRQ) module. It is also evident that EE-DQRA requires a minimum delay in comparison to IEEE802.15.4 and DQ-MAC, due to overhead minimization and M/M/K queuing utilization in DTQ system.

Investigation of Traffic Loading Effects for Different Codes on Medium‐ and Small‐Span Girder Bridges in China

With increasing traffic volume, the traffic load grade given by design codes has gradually increased. For new bridges, there is no problem, and the traffic load can be met through the requirements of the new code. However, for existing bridges, there is a lack of uniform standards on whether they can continue to be used. It is not clear whether these bridges will be judged according to the new code or the original design code. The traffic loading effects of different codes on medium‐ and small‐span girder bridges in China are investigated in this study. Three codes are introduced: JTJ 021‐89, JTG D60‐2004, and JTG D60‐2015. Simply supported girder bridges and continuous girder bridges are discussed. The traffic loading effects calculated based on JTG D60‐2015 are significantly larger than those calculated based on JTJ 021‐89. For simply supported girder bridges, most of the differences range from 20% to 40%, and the maximum value is almost larger than 60%. For continuous girder bridges, most of the differences in the positive bending moments are concentrated in the 20%∼40% range, while the differences in the negative bending moments range from 10% to 20%. Therefore, the differences in traffic loading effects calculated based on various codes cannot be ignored in actual bridge engineering. The conclusion in this study can provide a basis for bridge structure evaluation and life prediction.

Mechanical Response of Gasketed Bell‐and‐Spigot Joint of Concrete Pipeline under Multifield Coupling

Concrete pipe may suffer joint failure under the coupling effect of internal fluid and overlying load, which may lead to pipe leakage. Based on Abaqus and Fluent finite element software, a three‐dimensional refined model of drainage pipeline with gasketed bell‐and‐spigot joints and flow field model inside the pipeline was established. Fully considering the compression of the gasket during pipeline assembly and pipe‐soil interaction, the fluid‐structure coupling numerical simulation was carried out by using the MpCCI (Mesh‐based parallel Code Coupling Interface) platform, and the mechanical response of the concrete pipe joint under the multifield loads coupling effects of burial condition, traffic load, and internal fluid was studied. The accuracy of the coupling model was verified through the full‐scale tests that have been carried out. The influences of various factors on the circumferential stress and vertical deformation of the joint were mainly studied. The result reveals that the influence of different working conditions on the circumferential stress of the pipe joint is mainly concentrated on the crown and the invert of the joint, the areas vulnerable to tensile damage. The change of flow field leads to a slight difference in the vertical deformation of the joint, while variation in gasket hardness and cushion compactness has a certain influence on the vertical deformation of the joint. The change of buried depth has a negative correlation to the vertical deformation of the joint, and the change of load position has a significant nonlinear effect. The result provides a theoretical basis for further research on the mechanical mechanism of the pipeline joints during operation.

Effect of Freeze-Thaw Cycles on the Properties of Asphalt Pavements in Cold Regions: A Review

Asphalt pavements weaken over time due to the effect of environment and heavy traffic loading on paving constituents. Rutting, fatigue cracking and low temperature cracking are the major distresses responsible for degradation of the pavement and consequently leads to the failure of flexible pavement. Asphalt pavement is directly exposed to atmosphere and hence, suffers the effects of weather, environment and automobiles. Apparently, for a new asphalt pavement, even though there is no vehicle loading or other artificial activities, deterioration can also appear under climate and environment effects. In recent years, thermal cracks and low temperature distresses have become key concern for asphalt pavements in cold regions. In case of rutting of asphalt mixtures, aggregate characteristics play an important role, whereas, the properties of binder are more related to fatigue. Although the properties of asphalt binder can have a great influence on the performance of pavement, the role of aggregate gradation cannot be ignored in providing resistance to rutting and reducing permanent deformation. Gradation has significant effects on asphalt mixture’s Freeze-Thaw (F-T) durability. This paper reviews research conducted on the various properties viz., fatigue, rutting, air voids, compressive strength, etc. of bituminous mixes which are under the influence of F-T cycles. This paper also discusses the effect of F-T cycles on stability of bituminous mixes.