High Axle Load Research Articles

Istraživanje upotrebe betona i uvaljanog betona umjesto vruće bitumenske mješavine pri izgradnji kolnika autoceste u regijama s visokim temperaturama

This study examines the impact of temperature on the Cizre-Silopi highway’s bituminous hot mix asphalt (HMA) pavement, focusing on rutting issues exacerbated by high temperatures, which can reach up to 50 °C in the region. Despite rapid deterioration, especially under heavy truck traffic, the HMA pavement exhibited significant stability and flow resistance loss (approximately 52 %) between 20 and 50 °C. Concrete (C25) and roller-compacted concrete (RCC) pavements displayed minimal strength reductions under the same temperature conditions. These findings suggest that given the prevalent high temperatures and heavy axle loads in the region, concrete (C25) or RCC should be prioritised over HMA for pavement construction to enhance resistance against wheel rutting and temperature-induced damage. The observed rutting issues, even in the initial summer post-construction, underscore the urgency of adopting more temperature-resistant materials for road infrastructure under specified climatic conditions.

Pavement Service Life Prediction with PLAXIS 3D in Bangladesh

This research aims to forecast the service life of the flexible pavement in Bangladesh. The service life of flexible pavement is greatly affected by the climate and traffic load. Pavements are severely deteriorated by the overweight trucks, shortening their lifespan. The study aims to predict the service life of a flexible road using the PLAXIS 3D software. The PYTHON algorithm was utilized for the pre- and post-processing of new mechanistic empirical approach based on the AASHTO 2008 design standard. PLAXIS 3D was used for realistic soil & damage modelling and to obtain a reliable service life. Rajshahi City Bypass Nowhata Road was chosen as the study area for this study because the road condition of Nowhata is defected day by day and the number of moving vehicles with high axle load also increasing. This research has established to give the valid data to the authority according to the construction materials of flexible pavement to get better performance and proper use of materials. This road is constructed under the Road & Highway Department (RHD), Rajshahi Zone. This study shows realistic results based on temperature, soil data of subgrade and the materials property used in the PLAXIS 3D software and PYTHON programming language.

Application of the Machine Learning Method to Determine Spring Load Limits and Winter Weight Premium

Freight transportation plays a crucial role in sustaining the Canadian economy. However, heavy truck transportation also puts enormous pressure on roadway networks. Spring Load Restrictions (SLR) are implemented to minimize road damage caused by heavy traffic during the thaw-weakening season, and Winter Weight Premium (WWP) is used to reduce the impact of SLR on trucking operations by allowing higher axle loads in winter. However, existing policies apply fixed dates each year for these restrictions, regardless of the actual structural capacity of the pavement. Different methods have been proposed to improve the application of SLR and WWP; however, they rely mainly on indirect indices, such as the cumulative thawing index and cumulative freezing index, which pose challenges in their calculation. This study explores the practical implementation of machine learning models for accurately determining the start and end dates of SLR and WWP. In a novel approach, machine learning models directly derive the start and end dates of SLR and WWP from frost and thaw depths in the pavement structure which are determined by pavement temperature and moisture content. In contrast to previous studies that neglected the influence of soil moisture content on determining the start and end dates of SLR and WWP, this study examines the variation in soil moisture content to evaluate the validity of existing theories. The findings reveal a high level of agreement between the machine learning model’s estimations of frost and thaw depths and the measured values, with R2 values exceeding 0.91.

Evaluating the effect of paper waste lignin in hot mix asphalt

Asphalt is a viscoelastic material which performs to resist rutting, fatigue cracking, and moisture susceptibility under different loading and temperature conditions. The use of innovative and renewable pavement construction materials is inevitable due to high axle loads, rapidly increasing traffic volumes, and varying climatic conditions. This study aims to assess the effect as well as the optimum dosage of paper waste lignin for use in hot mix asphalt (HMA). Lignin from the paper industry with dosage ratios of 5, 10, 15, and 20%, was utilized to study the effect of the addition of lignin to the asphalt binder. Virgin and lignin-modified binder samples, before and after the aging process, were subjected to physical testing through penetration, softening point, ductility, viscosity and specific gravity and rheological characteristics through dynamic shear rheometer (DSR), bending beam rheometer (BBR), and rational viscometer (RV). The fractional composition was assessed through saturates, aromatics, resins and asphaltenes (SARA) fractional composition technique. Statistical analysis was also performed to find correlation of different physical and rheological parameters. Furthermore, based on optimum dosage, the performance of asphalt mixtures was studied against rutting, fatigue cracking, and moisture susceptibility. The results indicated that the addition of lignin has improved the physical properties significantly. The amount of asphaltene decreased and aromatics increased in SARA fractional analysis. Moreover, the Colloidal Instability Index (CII) has also indicated a stable structure of the binder. The rheological characteristics are improved after modification. The asphalt mixture tests revealed that addition of lignin with optimum dosage (10%) has improved the performance against rutting, fatigue cracking and moisture susceptibility. Statistical analysis indicated good co-relation among different physical and rheological parameters. This study concludes that 10% dosage is the optimum dosage that can successfully replace the virgin asphalt binder for performance of hot mix asphalt.

Development of track component health indices using image-based railway track inspection data

The primary role of the US Department of Transportation (USDOT) Federal Railroad Administration (FRA) is ensuring the safe operation of railway rolling stock and infrastructure by way of regulatory oversight. FRA regulations require US railroads to conduct visual track inspections as often as twice per week depending on a specific track segment’s FRA track class, which also governs maximum train operating speed. Such inspections are often subjective due to the inherent limitations of human visual inspection and cognition. Additionally, human visual inspections require some level of risk given the need for inspectors to be on track while also consuming valuable network capacity. As a result, and the desire to collect objective data to improve both safety and maintenance planning, railroads are pursuing new means and methods to assess track condition and evaluate track component health. This paper presents a numerical method to define track component health using field data collected on the High Tonnage Loop (HTL) at the Transportation Technology Center (TTC) in Pueblo, Colorado, USA. Line scan laser and image data of the track were captured using a 3D Laser Triangulation system and were subsequently processed using Deep Convolutional Neural Networks (DCNNs). The track heath quantification method proposed establishes benchmarks that were developed based on the understanding of railway track mechanics, high axle load (HAL) railroad engineering instructions, and FRA regulations. The novel metrics presented are referred to as Track Component Heath Indices (TCHIs) and are quantitative values that objectively assess track condition and provide a means to monitor condition change with time and tonnage. These data can be used in conjunction with traditional track geometry and other forms of track heath data (e.g. GPR and rail profile) to more holistically assess the condition of the track structure and its components and ultimately predict its future state.

INTEGRATED RESEARCH OF MULTI-PURPOSE STANCHION BASKETS FOR TRANSPORTING TIMBER AND CONTAINERS

Analyses of cargo transport in 2021 show that despite the increased volume of cargo transported by all types of transport compared to 2020, road transport is still dominant compared to rail transport. Therefore, all actions aimed at improving these unfavorable relations (rail transport vs. road transport) in transport, particularly cargo transport, should be considered purposeful and justified. One such activity is the ongoing work on the design and construction of freight wagons for specialized transport. Unlike universal wagons, specialized wagons are characterized by a limited ability to transport a wide range of material groups. An example is the transport of timber. However, the development of new transport technologies, and above all, technical and organizational progress, force the organizers of these transport modes to look for new logistic and rolling stock solutions. The aforementioned transport of timber is an example of this. The transport of wood does not constitute a large volume of transport, but taking into account its transport issues (transport with large truck tractors, high axle loads, and high risks for other road users), it is a classic example of the fact that it should not be carried out by road over long distances. Therefore, all actions aimed at reducing these issues and improving efficiency by using rail transport are desirable and even necessary. The article presents an innovative design solution in the form of a stanchion basket installed on flat wagons, allowing the use of standard wagons of this type to transport both containers and timber as well as loads such as beams and pipes. Such a solution will allow the use of empty runs of these wagons after unloading wood at the destination station for further transport of containers and vice versa. The considerations described in the article show the research process at the construction stage and testing the prototype of the built basket and the wagon with the stanchion basket structure placed on it.

Modelling of slab track systems for design purposes

Slab track is a recent technology used to cope up with the train high axle loads and speed, it has replaced the ballast material in classical ballasted track with either reinforced concrete slab or asphalt layer in order to increase both stability and durability of the railway lines. This paper aims to propose a new slab track design model which can be used to design/analyze any slab track systems under vertical loads using AREMA and EN specifications for high-speed systems (300 kmph). This model has been validated through experimental work held in Heriot-Watt University then applied to the most common slab track systems (BÖGL, Shinkansen, and RHEDA 2000) in the world. The standard section of RHEDA 2000 slab track has shown the best structural performance and efficiency compared with BÖGL and Shinkansen standard sections regarding the rail deflection, stresses of rails, and stress of replacement soil layer and subgrade soil. This paper has concluded the rail deflection is the most critical factor for the slab track design regarding EN specifications while the subgrade stresses is the vital criterion concerning AREMA specifications. Furthermore, EN-Specifications are found to be more conservative than AREMA specifications for the design or analysis of all the slab track types.

A Case Investigation into Causes of Premature Rutting Failures in Rehabilitated Asphalt Pavements in Tanzania

Abstract Tanzania has faced high incidences of premature rutting failures on their asphalt pavements. Some pavements experienced failures within one to two years after construction/rehabilitation. The objective of this investigation was to identify the factors that contributed to the observed failures on five rehabilitated road sections on a national highway in Tanzania. Pavement temperature data collection, traffic surveys, visual inspection, rut depth measurements, and falling weight deflectometer tests constituted the main activities of the field investigation reported in this paper. The laboratory study included a visual assessment of cores extracted from the studied road sections to determine both physical and engineering properties, including density, stiffness, strength, aggregate shape properties, grading, and physiochemical tests on the recovered binders. The results of the study indicated that the degree and extent of rutting on the investigated road sections was rated as severe., i.e., rutting ranged from 38–138 mm on the five sections when compared to the acceptable threshold value of 15 mm for high volume roads in Tanzania. The elastic deflection results indicated that the underlying layers of the pavement system were generally in a sound condition, which validated the suggestion that the rutting observed was mostly confined to the asphalt concrete layers. Factors such as relatively high axle loads, poor asphalt mixes, and possibly inadequate quality control during construction and rehabilitation were suspected to contribute to the rutting on the sections. Practical measures recommended to the roads agency to avert future occurrences are provided in this paper.

Effect of soil compaction and cover crop management on soil physical quality, biomass production and corn and soybean yield

ABSTRACT No-till with cover crop (CC) has been marketed to growers as a sustainable way to increase soil quality and crop yields. Our goal was to better understand the effect of CC management strategies on crop yield and mitigation of soil compaction. The compaction treatments were: four (C4) and eight (C8) wheel passes of a tractor, and without additional compaction (C0). CCs in autumn/winter were Italian ryegrass (IR) hay, IR as CC, and mix of IR and forage radish as CC. In the spring/summer, corn and soybean were cultivated. The reduction of hydraulic conductivity (0–6 cm depth) after first season in the IR hay was 74.9% in C4 and 96.2% in C8 comparted with C0. Overall, harvested CC has limited capacity to respond to compaction, decreasing root growth (root biomass of 2191, 2753, and 3744 kg ha−1, IR hay, IR CC, and mix, respectively). Further, the negative effects of compaction on crop yield were modest, probably because of the low axle loads and contact stresses; high inherent structural stability of Oxisols; and permanent no-till and CC roots which favored soil structure stability. Future works should use higher axle loads and surface stresses and a control treatment without CC.

Permanent Deformation Monitoring and Remaining Life Prediction of Asphalt Pavement Combining Full-Scale Accelerated Pavement Testing and FEM

Permanent deformation (rutting) is one of the typical failure modes of asphalt pavement with a semirigid base in high-temperature areas. To address issues of pavement structure deformation and remaining life prediction, a method of combining accelerated pavement testing and finite element (FE) simulation was proposed. A modified Burgers model considering creep parameter damage was obtained using strain monitoring data and laboratory test values, which was performed in the FE model to analyze rutting development. The results showed that high temperature and heavy axle loads greatly influenced rutting development: the tested road was loaded 360,000 times at high temperature, contributing 50% to accumulated rutting; rutting increased by 90.7% under the condition of 50% overload under high-temperature seasons from the simulated results. Then, the ratio of the bulge area to the depression area (KR) was proposed to define the rutting deformation mechanism. The KR analysis results illustrated that rutting development was a transition process from compaction rutting to flow rutting. Finally, the relationship between the action times of axle load in the tested and in-service roads was established based on the rutting equivalence principle. When the action times of axle load reach approximately 25 million times (insufficient remaining life) for the investigated Hu-Ning highway, necessary maintenance measures should be taken to treat rutting deformation.

Paving of concrete carriageway Case study Tauern motorway at the Wengen-Pongau junction

Passenger and freight traffic on our roads continues to increase in number and severity. High axle loads, high tyre pressures and greater dynamic loads require load-bearing and stable road pavements. Concrete road pavements are highly suitable for meeting these demands over long periods of time. Therefore, they are well suited for the new construction and renewal of motorways, federal and country roads, local bypasses, bus traffic areas, intersections and roundabouts, and cycle paths. Concrete road pavements have a long service life even under heavy use. Nevertheless, the production costs are competitive and the maintenance costs are low. This makes concrete pavements particularly economical by comparison.

Development of the chemical composition and modes of heat treatment of steel for railway wheels with increased wear resistance at high axle loads

One of the directions of the development of railway transport is increasing the load on the axle, while it is necessary to create new, more wear-resistant materials to increase the durability of railway wheels. At the same time, in many cases, a high level of hardness and strength must be combined with no less high values of plasticity and viscosity indicators. Purpose: to investigate the effect of the developed chemical composition and processing modes on the mechanical properties of laboratory-produced steels for railway wheels with increased wear resistance, which work in light braking conditions with high axleloads. Material and methodology. Research was carried out on steels of the experimental composition of the laboratory manufacturing method. Metallographic studies of experimental and industrial steels were performed on a light microscope "Neophot 32" and "Axiovert 200 M MAT" of the company "Carl Zeiss". Grinds were made mechanically. The microstructure was revealed by etching in a 2—3 % alcoholic solution of nitric acid (HNO3). Mechanical tensile tests at room temperature were carried out according to standard methods. Results. Based on the results of analytical studies and calculation models that allow predicting the mechanical properties of steels depending on the content of chemical elements in the steel, the chemical composition of small-volume experimental ingots for smelting in laboratory conditions was developed. Smelting of experimental melts has been completed. The possibility of obtaining a full set of mechanical properties and microstructure, standardized by the requirements of AAR M-107/M-208 for railway wheels of class D from developed steel, has been established.

The influence of the reliability of wheelsets of innovative wagons in operation on the need for new wheels

The article considers one of the most important wagon units - wheelsets. An analysis was made of the growing number of uncoupled wagons of Russian railways for unplanned repairs and it was revealed that the most common reasons for this are the faulty condition of the wheelsets and axle boxes. It was determined that the factors influencing the nature of the malfunctions are the inappropriate quality of the repair of bogies, the admission to operation of secondary wheels with a rib thickness of less than 26 mm. One of the measures taken is the lubrication of rails and sleepers. The introduction of innovative wagons with wear-resistant wheelsets may also have an impact on reducing the growth in the number of uncoupled wagons requiring repair. The features of newly produced innovative wagons with a higher axle load and an increased turnaround time are considered. To assess the impact of an increase in the share of innovative wagons on the need for wheels, the reliability indicators of wheelsets of innovative gondola and hopper wagons were considered. Reliability was evaluated by indicators of the probability of nonfailure operation, the failure rate parameter and the time between failures. An assessment was carried out for each type of identified malfunctions. The most common were a thin rib and a shelled tread. Results of the calculations showed the dependences of the number of uncoupled wagons on faults from the run of wagons to uncoupling were defined. The probability of nonfailure operation of the wheels of the studied wagons was determined. It has been determined that the average mileage before a malfunction occurs for innovative gondola wagons is 3.5 times greater than for traditional wagons.

Assessment of an old reinforced concrete open-spandrel arch railway bridge

This paper presents assessment of a 94 years old reinforced concrete (RC) open-spandrel arch bridge with a total length of 285 m having seven major spans of 35 m, a height of 34 m and a vertical slope of 15 ‰. As the bridge was currently subjected to heavy trains having higher axle loads than it was originally designed, assessment of its actual structural condition was necessary. To determine actual in-situ behavior of the bridge, dynamic tests including a series of acceleration measurements along the bridge spans were performed. Then, 3D finite element model of the bridge was generated by using a structural analysis software based on its original constructional drawings. The initial FE model was updated using Response Surface Method (RSM) technique based on the results obtained from measurement data. The updated FE model was used for structural assessment and evaluation of the bridge under UIC-71 live loading. Rating factor and reliability index for each bridge member based on Load and Resistance Factor Rating (LRFR) approach were obtained. Results of the rating and reliability analysis showed that the most critical member of the bridge was the deck, thus strengthening and retrofitting of these deck members might be needed for live loads greater than those induced by UIC-71 train.

Evaluation of Indonesia's Conventional Track Performance Based on Mechanistic Approach

Most railway track dynamics models focus on the high-speed train. However, freight trains non only have strong implications for track dynamics, but also the response of conventional track subjected to the low speed of freight train models are rarely published. This paper developed a 2-Dimensional conventional railway track model based on the multipurpose finite element package Abaqus/CAE, which considers four structure layers: sleepers, ballast, sub-ballast, and subgrade subjected to three different freight train speeds (very low, low, and normal) and two different freight train axle loads (normal, 18,000 kg, and heavier, 27,000 kg). The most obvious finding to emerge from this study is that running the long-chain coal "Babaranjang" freight train with 70 km/h of operating speed and 27,000 kg of axle load is suggested to increase the hauling capacity of the Babaranjang train and at the same time to ensure the safety of its operation. Also, the present study confirms previous findings and contributes additional evidence that a train with a very low operation speed could deteriorate the conventional track structure, and it will be worsened when this type of train is operated with a higher axle load.

Structural analysis and parametric study ballasted track in sandy regions

The sand intrusion in railway tracks in sandy regions can significantly change the mechanical behaviour of tracks and thus threaten the safety of train operation. This paper presents substantial field tests on both sandy and clean railway tracks to study the effect of sand intrusion on the longitudinal resistance of ballast bed and the vibration behaviour of track structures. After that, a 3D multi-scale the discrete element model is developed to study the micro-contact between ballast particles and the vibration behaviour of sandy tracks during train passing in detail. Also, the effect of train speeds and axle loads on the mechanical behaviour of sandy tracks is discussed. The results show that the sand intrusion increases the vibration acceleration amplitude of rail and sleeper by 11.3% and 50.3%, while ballast bed decreases by 44.9%. Besides, the sand intrusion significantly changes the energy distribution in the track, wherein the frequencies of the highest energy of rail and sleeper are increased while that of the ballast bed is decreased. The parametric study shows the high train speed can cause the increase in overall acceleration of the ballast bed and high axle load can cause an increase in the micro-contact forces between ballast particles, diffusion angle of the contact force chain, displacements of ballast particles, acceleration of ballast particles, and sleeper displacements.

Microstructure and Cyclic Deformation Behavior of Wheel and Tire Steels in Technically Relevant Heat Treatments

Abstract The present developments of rail-mounted traffic aim at higher speeds in the passenger and higher axle load in the freight traffic. As a consequence, a substantial increase of the loading of the wheels has to be regarded. Geometric changes at wheels and rails cause high cyclic loading in the dynamic system wheel/rail as a function of the course rate [1– 6]. Since for wheel steels only a few systematic investigations of the fatigue behavior are available so far, the actual investigations concentrate on the relation between the local microstructure and the description of the fatigue behavior of highly stressed wheel steels. As test materials monoblock wheel steels and tire steels were selected in accordance with UIC specification in technically relevant heat treatment conditions. The cyclic deformation behavior is characterized and evaluated by stress – strain hysteresis as well as thermometrical and electrical measurements.

Assessment of Modulus Attenuation of Cement and Lime-Fly Ash Semi-Rigid Road Base Materials

For asphalt pavement structures, semi-rigid road base course has to sustain repeated high-axle load during its service life and the performance of semi-rigid road base materials directly influences the durability of pavement structures. The dynamic compressive resilience modulus of two commonly used semi-rigid road base materials, cement stabilized aggregates (CSG) and lime-fly ash stabilized aggregates (LFSG) were evaluated at different frequencies using a Universal Testing Machine (UTM). The results showed that LFSG had higher dynamic modulus than that of CSG and the load frequency had less influence on the dynamic modulus of these two semi-rigid road base materials. The four-point bending test was applied to measure the flexural-bending strength and the fatigue life of these two semi-rigid materials. A higher flexural-bending strength of LFSG indicated its better bearing capacity than that of CSG. The fatigue life of LFSG and CSG decreased with the increase of stress–strength ratio and the LFSG performed better in terms of fatigue resistance. The fatigue damage models of CSG and LFSG based on Stress-Life (S-N) curve are established. As per incremental-recursive mechanics, a general modulus degradation model was established and verified by the results of full-scale accelerate loading test. This model cannot only be used to predict the fatigue deterioration of semi-rigid road base materials under different stress levels, but is also able to calculate the current bending elastic modulus based on its initial modulus value.

PERFORMANCE EVALUATION OF ETHYLENE-VINYL ACETATE MODIFIED BITUMEN AND MIXTURES

Interconnectivity necessitates the use of transportation facilities and infrastructure. All highway design agencies seek acceptable, long-lasting, and cost-effective strategies while designing these facilities. The traffic demands on roads are much higher than they have been in the past. Increased traffic loads, larger traffic volumes, and insufficient maintenance have all contributed to serious road surface distress (e.g., rutting and cracking) due to rapid development. As conventional asphalt combinations are unable to withstand high axle loads and tire pressures, interest in polymer-modified asphalt has grown. Polymer modification of asphalt is one of the most effective ways to improve asphalt qualities. The practical temperature range of binders is greatly expanded by polymers. The inclusion of the polymer can considerably improve the binder qualities by increasing the stiffness of the bitumen and enhancing its temperature susceptibility, enabling the building of safer roads and lower maintenance costs. This research presents a laboratory investigation of the Ethylene Vinyl Acetate (EVA) polymer-modified bitumen. NHA-B gradation, PARCO 60/70 grade bitumen, and EVA polymer of TPI Polene Public Company Limited were used. Penetration, softening point, ductility, and viscosity tests were used to evaluate the conventional properties of the asphalt binders. Three different percentages of polymers were used i.e., 2%, 4%, and 6%. The impact of the EVA polymer on permanent deformation and moisture susceptibility was investigated. A double wheel tracker (DWT) was used to quantify permanent deformation (rutting), and a Universal Testing Machine (UTM) was used to examine moisture susceptibility using an Indirect Tensile Strength (ITS) test. For different percentages of bitumen volumetric properties according to Marshall Mix Design procedure were measured, and then Optimum Bitumen Content (OBC) was evaluated. Performance tests were performed using above mentioned percentages of EVA. The rutting potential of mixes was improved by the addition of EVA as compared to control asphalt mixes. The same effect of the polymer was on the moisture susceptibility of the prepared samples. This showed that EVA polymer can be used in flexible pavements to reduce permanent deformation and high-temperature problems.

Modeling the Effect of Wheel Traveling on the Soil Surface on the Load of Buried Structure

As a result of the technical development of agriculture, machines with very high axle loads appeared in the fields and on farm roads. As a result, subsurface soil pressure values will also increase, which will ultimately put increased stress on underground pipelines and other structures. In our paper, we show the possibility of modelling the problem using explicit dynamical methods by means of a simple example.