Road Test Sections Research Articles

Proposed structural and functional evaluation of unpaved roads improved with geosynthetics, reclaimed asphalt pavement and Portland cement

The cargo transport network in Brazil is highly unbalanced, with a marked concentration of road transport in relation to other modes of transport. As if the flagrant imbalance between modes were not enough, serious distortions are also observed in the distribution of road network coverage. Only 13% of the Brazilian network has coating considered definitive, reinforcing the importance of unpaved roads in the transport network. Despite advances, the design methods for unpaved roads were mostly developed for roads treated with gravel in regions with a temperate climate, which are inconsistent with the nature and behavior of Brazilian tropical soils. They also disregard important soil improvement techniques, such as reinforcement with geosynthetics, incorporating civil construction waste, reclaimed asphalt pavement, mining tailings or chemical stabilization with different additives (hydrated lime, Portland cement, latex polymers, organic additives and asphalt emulsion). Faced with this challenging scenario, this research was designed to monitor the structural and functional conditions of unpaved road test sections in Brazil built with different soil reinforcement and stabilization techniques. The structural condition of the test sections will be evaluated through deflection measurements with the Light Weight Deflectometer (LWD), Benkelman beam, and Falling Weight Deflectometer (FWD), and the functional condition will be evaluated through field inspections for the qualification and quantification of defects. This article aims to present the synthesis of the proposed methodology and the initial results of soil characterization obtained in constructing the first test section located in an unpaved section of the Federal Highway BR-030, in the state of Bahia.

Preliminary Selection of Road Test Sections for High-Mobility Wheeled Vehicle Testing under Proving Ground Conditions

Before being introduced into the maintenance system, each vehicle must undergo a series of tests, including durability tests. Computer models and whole vehicles on test stands can be used to identify vehicle performance parameters, which requires access to special software and test stands. However, due to the size of the vehicle or access to test stands, experimental tests must often be carried out on proving grounds; while generating the most complete set of loads, this is much more time-consuming. Therefore, methods are sought to indicate whether testing at the proving ground can be accelerated, for example, by increasing the speed of driving or using test road sections that generate more severe loads. This paper presents a method for evaluating the suitability of selected test road sections for durability tests of a special high-mobility wheeled vehicle. The method is based on the Basquin model, which consider the fatigue strength of materials, and rainflow load cycle counting method combined with the P-M damage summation method. Evaluation of test road selection was supplemented with analysis of travel speed distributions determined using the Beta statistic distribution. The presented model was used to evaluate the ability to accelerate a mileage test of an 8 × 8 vehicle. While certain data mentioned in the article remain classified and are not able to be presented in full, the author has attempted to provide a comprehensive background of the analyses conducted and the data used to illustrate them.

Evaluation of geosynthetic reinforcement in unpaved road using moving wheel load test

The common cause of failure of the unpaved road is associated with undesirable ruts and deformations. Use of geosynthetic reinforcement is a solution to this pavement distress problem as experienced in limited research works, especially in the laboratory studies. This study presents the performance of geosynthetic-reinforced unpaved roads subjected to moving wheel load tests to investigate the effect of geosynthetic reinforcement on the pavement surface deformation of the unpaved roads. Unreinforced and geosynthetic-reinforced unpaved road test sections consisting of varied reinforcements were constructed in a test pit, 9 m long and 2.7 m wide. Geogrid and geotextile were used for reinforcing the unpaved road test sections. The rut depth was measured in the transverse direction of the wheel path after certain number of wheel passes. Traffic Benefit Ratio (TBR) and Performance Index (PI) were employed in the study for the evaluation of the effectiveness of geosynthetic reinforcement in unpaved roads. After 350 vehicle passes, the geotextile-reinforced and geogrid-reinforced test sections get rutting reduced by 44.89% and 28.57%, respectively. The test results indicate that inclusion of geosynthetic reinforcement significantly improves the rutting resistance and stability of reinforced test sections compared to the unreinforced test sections.

Influence of the Car Movable Aerodynamic Elements on Fast Road Car Cornering

In the case of road cars, road safety is the primary factor. The geometry of high-speed road cars has no regulatory restrictions. In addition to the high engine power and effective shape, they can use various types of additional movable aerodynamic elements to adjust their aerodynamic characteristics to the road conditions. Based on the geometry of a two-seater prototype of such a vehicle, a numerical analysis of the influence of a number of additional movable aerodynamic elements on its aerodynamic characteristics was performed. Several of them were installed on the prototype. An electronic system recording a number of motion parameters of the entire car body and some of its movable elements installed on the body was designed and built. The system has been adapted to program the motion of additional aerodynamic elements according to the set algorithms of their activation, temporarily changing the aerodynamic characteristics of the car. An experimental study of the effect of changes in the aerodynamic characteristics of the prototype on its dynamic properties during a drive through a test road section was carried out. It was shown to what extent an average driver can increase the safe speed of the curve of the road using the possibilities of moving aerodynamic elements installed on it.

Strategies to Facilitate Photovoltaic Applications in Road Structures for Energy Harvesting

Photovoltaic (PV) facilities are sustainable and promising approaches for energy harvesting, but their applications usually require adequate spaces. Road structures account for a considerable proportion of urban and suburban areas and may be feasible for incorporation with photovoltaic facilities, and thereby have attracted research interests. One solution for such applications is to take advantage of the spare ground in road facilities without traffic load, where the solar panels are mounted as their conventional applications. Such practices have been applied in medians and slopes of roads and open spaces in interchanges. Applications in accessory buildings and facilities including noise/wind barriers, parking lots, and lightings have also been reported. More efforts in existing researches have been paid to PV applications in load-bearing pavement structures, possibly because the pavement structures cover the major area of road structures. Current strategies are encapsulating PV cells by transparent coverings to different substrates to prefabricate modular PV panels in factories for onsite installation. Test road sections with such modular solar panels have been reported, where inferior cost-effectiveness and difficulties in maintenance have been evidenced, suggesting more challenges exist than expected. In order to enhance the power output of the integrated PV facilities, experiences from building-integrated PVs may be helpful, including a selection of proper PV technologies, an optimized inclination of PV panels, and mitigating the operational temperature of PV cells. Novel integrations of amorphous silicon PV cells and glass fiber reinforced polymer profiles are proposed in this research for multi-scenario applications, and their mechanical robustness was evaluated by bending experiments.

Road Hazard Assessment Using Pothole and Traffic Data in South Korea

Road surface conditions have a direct effect on the quality of driving, which in turn affects overall traffic flow. Many studies have been conducted to accurately identify road surface conditions using diverse technologies. However, these previously proposed methods may still be insufficient to estimate actual risks along the roads because the exact road risk levels cannot be determined from only road surface damage data. The actual risk level of the road must be derived by considering both the road surface damage data as well as other factors such as speed. In this study, the road hazard index is proposed using smartphone-obtained pothole and traffic data to represent the level of risk due to road surface conditions. The relevant algorithm and its operating system are developed to produce the estimated index values that are classified into four levels of road risk. This road hazard index can assist road agencies in establishing road maintenance plans and budgets and will allow drivers to minimize the risk of accidents by adjusting their driving speeds in advance of dangerous road conditions. To demonstrate the proposed risk hazard assessment methodology, road hazards were assessed along specific test road sections based on observed pothole and historical travel speed data. It was found that the proposed methodology provides a rational method for improving traffic safety.

3D laser scanning and surveying adjustment in traffic infrastructure management

In view of difficulties in automatic and refined management of traffic infrastructure, road lamps and signboard in the test road section are taken as examples, an application framework for automatic and refined management of traffic infrastructure is proposed by using 3D laser scanning technology combined with GPS (Global Positioning System) and QGIS (Quantum Geographic Information System). The advantages of 3D lidar sensor, such as high precision, strong anti-interference ability and good real-time performance are fully used. Through data fitting by using total least squares method, digital management of infrastructure is carried out and its precision is high. Combined with GPS and QGIS, the spatial information of infrastructure is developed. In this way, manpower and efficiency of management of infrastructure are saved and improved.

Construction, instrumentation and field performance of geogrid-reinforced unpaved roads

A research study involving full-scale unpaved road test sections was carried out to investigate the performance of unpaved roads reinforced with geogrids. Ten test sections were constructed with two different base course thicknesses. Three biaxial geogrids of different tensile stiffness and one geogrid with triangular aperture were evaluated. Geogrids were placed at the subgrade–base course interface. The sections were instrumented for measuring road response to traffic loading. Traffic loading was provided by a single-axle dump truck. Field measurements of rut depth and surface deformation were recorded at selected traffic intervals. An analysis of the measured performance data indicated that the geogrids effectively reduced surface rutting and improved the performance of unpaved thin base layers and the benefit became more pronounced when a stiffer geogrid was used. The results suggested reductions in the thickness of the base layer by using geogrids of up to 18%. The improvement by geogrids was shown to be less for increasing base layer thickness. In addition, the ability of the design procedure by Giroud and Han to predict rutting performance using the test section parameters as design inputs was assessed. The results indicated that the method underpredicted the required base thickness to support the applied traffic loads.

Evaluation of ecological extremes of vehicles in road emission tests

New testing procedures for determining road emissions of exhaust pollutants for passenger vehicles were established in 2018. New road testing procedures are designed to determine actual exhaust emissions, which may not always reflect laboratory emissions. Test procedures for the emission of pollutants in real traffic conditions are divided into four stages. The latest research on the emission of pollutants from motor vehicles in road traffic conditions, carried out using mobile measuring systems, reflects the actual ecological state of vehicles. The article compares the results of exhaust emissions obtained in road tests using the latest legislative proposals for passenger cars. Then, an attempt was made to determine the engine operating parameters in which exhaust road emission would be the lowest. Solution scenarios were defined as part of permissible changes to dynamic parameters that are included in European legislation on RDE testing. For this purpose, an optimization tool was used, allowing on the basis of given input data to determine the minimum objective function, defined as the smallest emission value of individual harmful compounds. The results of the exhaust gas emissions in the RDE test were used to determine the road emissions of individual harmful compounds. A thorough analysis of the emission intensity of individual compounds has shown that it is possible to approximate such values using functional relationships or adopting them as a constant value. This division was used to determine the extremes (in this case the minima) of the objective function (minimum road emissions of harmful exhaust compo-nents). This task resulted in obtaining (within the permissible tolerances of all driving parameters and durations of individual road test sections) the value of exhaust emissions in the range from 26% to 81% lower than in the actual road test. This means that there is a tolerance range, where you can obtain the value of emissions in road tests. As a result, you can use the process of determining the minimum emissions tests RDE calibration of the drive units already at the stage of preparation so that in the real traffic conditions characterized by the lowest exhaust emissions.

Mechanistic Analyses of Geosynthetic Reinforced Aggregate Road Test Sections

Large-scale laboratory box tests and a full-scale traffic test were performed by the U.S. Army Engineer Research and Development Center to evaluate the performance of geosynthetic reinforced aggregate road sections constructed with marginal base materials over a typical subgrade. The large-scale laboratory testing and full-scale test section included eight different instrumented aggregate road sections including three different aggregate base materials and two different geosynthetics. Mechanistic analyses of each pavement section were conducted using linear elastic, nonlinear elastic, and nonlinear anisotropic models to predict the critical pavement response parameters. The analyses show that mechanistic tools can be effectively used to estimate the critical pavement response parameters for unpaved roads.

Problemy oceny trwałości wybranego elementu pojazdu na podstawie przyspieszonego testu przebiegowego

The paper presents the results of the analysis of the durability of elastic elements occurring in the special-purpose 4x4 off-road truck suspension using data obtained during an accelerated proving ground test conducted during off-road driving. The limitations in access to material data present at the stage of the initial selection of the component (lack of fatigue strength data) are indicated and an alternative analytical method for fatigue strength estimation is given. The differences in the obtained results and their most important sources are pointed out. A method for using a generalized durability index d as a parameter independent of the subassembly material data is also described. The indicator can be used to assess the influence of resultant loads (recorded) appearing during the vehicle operation in the determined road conditions on the durability of the subassembly under study and to associate their value with the type of the test road section.

Research on AS Infiltration Maintenance Agent to Performance Improvement of Asphalt Mixture

The AS infiltration maintenance agent is a new kind of inorganic and special material for preventive maintenance of asphalt pavement. It depends on the effects of infiltration and crystallization to form a unique three-dimensional reinforced network structure on the surface and in the fine cracks of asphalt concrete, then the pavement performances such as high temperature and water stability etc. of asphalt pavement are improved. In order to research its improvement effects, the common asphalt mixture of SBS modified AC-13C for surface layer is selected as the brushing matrix. Through the laboratory testing, the comparative analysis were conducted to various pavement performances of AC-13C before and after the AS agent brushing, and the validation of field test road section was also conducted. The results show that the AS agent meets the technical requirements of infiltration film-forming waterproof coating. After the AS agent brushing, the impermeability, bond strength and wear resistance of SBS modified AC-13C are improved significantly, all the high temperature stability, low temperature crack resistance, water stability, aging resistance and corrosion resistance capability of acid and alkali etc. are gotten some improvements, but the skid resistance performance is impacted to a certain. Therefore, the AS agent can be applied to the preventive maintenance of asphalt pavement.

Temperature and Moisture Variation in Pavement Structures of the Test Road

Environmental conditions (temperature, moisture, intensity of sun, etc.) influence variation in asphalt pavement strength during the year. Lithuania is situated in a zone of cool average climate characterized by average warm summers and average cold winters. One of the most important climatic factors is the air temperature variation per day. In order to evaluate the dependence of road pavement strength on temperature and the dependence of Eo modulus of separate layers on seasonal factors a comprehensive research was carried out on the unique Test Road section that was constructed in 2007 in Lithuania and is operated almost for 8 years. This road is affected by real climatic conditions and high intensity heavy vehicle traffic. It consists of 27 different flexible pavement structures with the same class of pavement structure but the different type and composition of materials and all necessary electronic sensors (loop profilers, temperature and moisture sensors, stress and strain transducers). Temperature and moisture sensors are installed in 4 different pavement structures. In order to analyse behaviour of asphalt pavement structure under Lithuanian climatic conditions, taking into account temperature and moisture, as one of the most important climatic factors influencing structural strength of road asphalt pavement, the experimental research was carried out and results are presented in the article.

Applicability of portable tools in assessing the bearing capacity of forest roads

Forest roads provide access to logging sites and enable transportation of timber from forest to mills. Efficient forest management and forest industry are impossible without a proper forest road network. The bearing capacity of forest roads varies significantly by weather conditions and seasons since they are generally made of poor materials and the constructed layers may be mixed with subgrade. A bearing capacity assessment is valuable information when trafficability is uncertain and rutting is obvious. In this study, bearing capacity measurements were carried out using the light falling weight deflectometer (LFWD), the dynamic cone penetrometer (DCP) and the conventional falling weight deflectometer (FWD). The aim was to compare their measurement results in relation to road characteristics and moisture conditions. Data were collected from 35 test road sections in four consecutive springs and during one summer. The test road sections had measurement points both on the wheel path and the centre line. The data show logical correlations between measured quantities, and the study presents reliable regression models between measuring devices. The results indicate that light portable tools, the DCP and the LFWD, can in most cases be used instead of the expensive falling weight deflectometer on forest roads.

Numerical Simulation and Structural Mechanical Analysis of Asphalt Pavement due to Abrupt Temperature Drop

Due to the natural condition of the sudden temperature drop when the cold wave strikes the north part of China in winter, especially XinJiang province, the asphalt pavement structures need to be compared. Based on the pavement structures of the test road sections andthe domestic major pavement structures in other provinces, seven pavement structures were chosen. The numerical simulation of these seven pavement structures was performed and the force situations were analyzed respectively under the condition of extreme climate environment, which is the condition of cooling 40 °C from 0 °C in winter. The analysis of the temperature-load coupling of these pavement structures from seven different base forms were conducted. The comprehensive comparison was also made, such as stresses and strains at the bottom layer of asphalt, the stresses of the base, the shear stresses of the asphalt layer, and the compressive strains of the top of base, etc., in order to choose the preferred and most adapted asphalt pavement structure form.

Analysis of Driver Visual Characteristics Based on FaceLAB

Driver visual characteristics are of great importance for studying driver behavior and traffic safety. To investigate the difference of visual characteristics between skilled and fresh drivers, FaceLAB was used to collect visual data. Four drivers including male and female, skilled and fresh one were selected as the subjects. A suburbs road was chosen as the test road section and each driver drove several times on it. Based on the FaceLAB working mechanism and human eye diopter, correlation between head rotation and eye fixation point were derived and some important conclusions were drawn. For skilled drivers, they are relax at capturing traffic environment information and could obtain much more critical information in a rather large range while keeps the head constant. However, for the fresh drivers, they are much more carefully at getting visual information and the information capture process takes up much more time. Therefore, they could only get little information while keeps the head constant.

Long Term Monitoring of Performance Characteristics of the Pavement Test Track

This paper presents the first experimental pavement test road section in Lithuania including pavement design, annual measurements, data acquisition and response analysis. The road of experimental pavement structures was constructed in 2007. It’s laid on the road to the query, one traffic lane is used by loaded traffic and other – by unloaded traffic. The road consists of 27 different pavement structures with the same class of pavement structure but the different type and composition of materials. Final results after five years of monitoring indicate the performance of typical Lithuania flexible pavement structures influenced by different traffic loads. The total number of ESAL’s (100 kN) in February 2013 was 353 000.

Reuse of thermal power plant slag in hot bituminous mixes

The revalorization of industrial waste plays a key role in the solution of environmental and economic problems in the construction sector, thus actions contributing to the symbiosis between industries in the same region are of great benefit since they optimize resources in the area and also open the door to new business opportunities. In recent years, the electricity produced by thermal power stations has become a renewable energy source of great potential. Nevertheless, this type of energy is not without drawbacks because of the coal ash and boiler slag produced by coal combustion. Although the ash has different application as a construction material, boiler slag is more problematic since it must be deposited at landfills. The accumulation of this waste has become a serious economic and environmental problem. This paper presents the results of a research project, which analyzed the viability of reusing thermal power plant slag as a substitute for natural aggregate in the manufacture of hot mix asphalt (HMA). For this purpose, the waste was first characterized and tested in the laboratory with a view to its subsequent use in HMA. Based on the positive laboratory results, a test road section was built with this material so that its performance could be compared with that of the road section paved with a conventional HMA. The results obtained confirmed the aptness of thermal power plant slag for use in road construction.

Portable Laser Profiler를 이용한 도로 포장의 노면조직 깊이 측정 방법 연구

PURPOSES : Skid resistance and noise of roads highly depend on the characteristics of pavement texture. Therefore, estimation of texture characteristics may give useful information for the skid resistance and noise of road. Generally, Sand Patch Test is performed in order to estimate MTD(Mean Texture Depth). However, it is time-consuming and needs traffic control. This study aimed to investigate the effectiveness of measurement texture depth using the Portable Laser Profiler that give the MPD(Mean Profile Depth). METHODS : MTD and MPD were collected on the number of expressway sections including Central Inland Test Road sections in Korea. Statistical analysis are performed to establish the relationship between MTD data based on Sand Patch Test and MPD data obtained by the Portable Laser Profiler. RESULTS : Linear relationship MPD and MTD is observed for both of asphalt pavement and concrete pavement such as R-square of 0.51 to 0.58. CONCLUSIONS : Even though, the test method and definition of MPD and MTD are different. EMTD(Estimated Mean Texture Depth) can be obtained by using the correlationship between MPD with MTD.

Life Cycle of Hot In-Place Pavement Recycling

It is no secret that all levels of government face unprecedented levels of deficits. While revenues drop, the costs to maintain infrastructure grow with its age. The question of sustainability takes center stage. Can the United States afford to keep its highway assets, all 3 million miles of its paved roads? The study reported in this paper examined hot in-place pavement recycling (HIPR) as a way to reduce the cost of pavement rehabilitation. The Florida Department of Transportation built a test section in 2002 and a control section in 2003 to compare the cost and performance of HIPR with conventional milling and resurfacing. After 8 years, in-service data were used to draw some conclusions. The test and control road sections performed well. The HIPR section was built at less than half the cost of the conventional section. Projections showed that HIPR was cost-effective and would save 40% more than the conventional method of pavement rehabilitation. These cost savings, taken together with derived environmental benefits, make pavement in-place recycling an option that should not be ignored.