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Road surface characteristics are the core influencing factors for tyre/road noise generation mechanisms. Dependingon the pavement wearing layer mixture composition, type surfaces have different acoustical properties. Acoustical parametersand acoustical behavior change over the time because of the effects of traffic and environmental conditions. Usually low noisepavements can be characterized with very good acoustical parameters but at the same time good acoustical properties deterioratesover the time. Paper presents the research study of surface type and age effects on tyre/road noise levels. Number ofdifferent age and different surface type pavements (conventional AC and SMA pavements, low noise SMA TM, TMOA andPA) were evaluated and compared in terms of acoustical performance. Analysis of CPX noise level measurement results arepresented in the paper followed with the conclusions and recommendations of low noise pavement application for severe climateregions. DOI: https://doi.org/10.3846/enviro.2017.152

Road accidents are one of the leading causes of death in the world, particularly among young people. Excessive speed is one of the main risk factors in road traffic safety, increasing accident probability and affecting accident severity. Experimental research of the traffic calming measures allocation effect on the driving speed is presented in this paper. The research has been carried out on two aspects. The first one with respect to the mean speed and the second one regarding instantaneous speed. However, the paper is not only restricted by the above research. Standardized survey interview and questioning, a survey of public opinion, was carried out to find out the road users’ opinions about the need for traffic calming measures and speed control measures. Finally, the authors presented their insights and recommendations for the installation of speed humps and gateways and their optimum spacing.

In Lithuania, it has always has been an important issue to find durable and cost-effective solutions for paving low-volume roads. The conventional asphalt concrete structures were built using paving grade bitumen with the penetration of 70/100 or 100/150 over the recent 20 years. The performance of those pavements was satisfactory. As an alternative solution, the use of soft asphalt pavements was proposed. This technology is widely used in Nordic countries. But in Lithuania it has never been applied. Research on the designed soft asphalt mixtures was carried out and the trial on-site sections were constructed. The results of laboratory tests and on-site research were positive and promising. Based on that, the technology could be considered as successfully implemented and good quality was achieved.

Road transport is by far the most convenient way of transportation these days, offering the highest mobility and flexibility. While road transport is gaining popularity, the increased amount of traffic requires proper improvements and maintenance of the road network. The increasing usage of roads requires highest levels of maintenance of the road network. To ensure that, new methods with the ability of rapid, non-destructive monitoring and testing of the construction properties are on demand. Review and analysis of flexible road pavement testing means and methods are presented in this paper to introduce the problem and current technology. Complexity of these methods is pointed out. New approach to pavement testing using vibro-excitation and logarithmic decrement analysis of extinguishing free oscillations is proposed and its advantages are shown with application possibilities in a new advanced non-destructive pavement structure research device.

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.

Atmospheric pollution began to increase in the beginning of 19th century, when the global economy and industrial development started the signal grow. The current problem of global warming is partly related with emission of carbon dioxide (CO2) to environment, which one of the sources are industrial production companies. Warm asphalt mix is usually used in the practice of Lithuania and the world for equipment of road paving. These mixes are produced in specialized asphalt mixers where stone dosing, drying and its mixing with bituminous binders are performed. The temperature of produced hot asphalt mix in mixer reach 150–180 °C and 120–160 °C of mixture laying on the road. Various pollutants, carbon dioxide, formaldehydes, and other are spread to the environment. The carried out researches in Lithuania and the world have showed that while using special additives it is possible to reduce the temperatures of warm asphalt production and laying on the road. Such reduction of temperature helps not to worsen the quality of asphalt layer, to lower the emission of pollutants to environment, to improve the conditions of road workers and to economically use the gas for production of asphalt mixes. Production technologies of different asphalt mixes, their advantages and disadvantages, and results of laboratory tests are analyzed in this article. Equipment samples of experimental road sections, using the warm mixing asphalt mixtures are given. Santrauka 19 amžiaus pradžioje, ėmus sparčiai augti pasaulinei ekonomikai ir vystytis pramonei, pradėjo didėti ir atmosferos užterštumas. Dabartinė globalinė pasaulinio atšilimo problema iš dalies siejama su anglies dioksido (CO2) išmetimu į aplinką, kurio vienas iš šaltinių yra pramoninės gamybos įmonės. Automobilių kelių dangoms įrengti Lietuvos ir pasaulinėje praktikoje dažniausiai naudojami karšto asfalto mišiniai. Šie mišiniai yra gaminami specialiuose asfalto maišytuvuose, kuriuose akmens medžiagos dozuojamos, džiovinamos, maišomos su bituminiais rišikliais. Gaminamo karšto asfalto mišinio temperatūra maišytuve siekia 150–180 oC, o kelyje klojamo – 120–160 oC. Šių procesų metu į aplinką paskleidžiama įvairių teršalų: anglies dioksido, formaldehidų ir kt. Pasaulyje ir Lietuvoje atlikti moksliniai tyrimai parodė, kad naudojant specialius priedus galima sumažinti karštų asfalto mišinių gamybos bei klojimo kelyje temperatūrą. Toks temperatūros sumažinimas leidžia nepabloginti asfalto dangų kokybės, sumažinti teršalų išmetimą į aplinką, pagerinti kelyje dirbančių darbuotojų darbo sąlygas, ekonomiškiau naudoti asfalto mišinių gamybai reikalingas dujas. Šiame straipsnyje analizuojamos skirtingų asfalto mišinių gamybos technologijos, jų privalumai ir trūkumai, laboratorinių bandymų rezultatai. Pateikiami eksperimentinių kelių ruožų įrengimo pavyzdžiai, naudojant šiltojo maišymo asfalto mišinius. Reikšminiai žodžiai:šiltojo maišymo asfaltas, ceolitas, CO2 sumažėjimas.

In 2012, the Lithuanian Road Administration initiated a three-year research project ‘The study of effective winter road maintenance of national significance roads in Lithuania’. The main purpose of this research was to optimize road maintenance in winter and to determine the most effective means of combating slippery conditions. The research project was carried out by two institutions: the Road Research Institute of the Faculty of Environmental Engineering of Vilnius Gediminas Technical University and JSC ‘Problematika’. JSC ‘Problematika’ conducted exploratory experiments, which were divided into two phases. In the first phase of the experiment, five different snow melting materials (Slipperiness Reducing Materials – SRMs) were investigated in the laboratory. Different test methods were used in this investigation. In the second phase of the experiment, three SRMs with different properties were selected, and experimental road sections were set up to determine the road slipperiness and the change in coating layer thickness over time concerning different environmental conditions, as well as different snow and ice layer thicknesses. An optical remote sensor of Road Condition Monitor (RCM 411) was used for friction measurements on the roads. This report covers the laboratory test results of five different SRMs, road slipperiness measurement results using three selected SRMs and their analysis, comparison of the performance efficiency of the most widely used SRMs in Lithuania and the tested SRMs under different environmental conditions.

The roads as main national assets maintenance costs increase dramatically but budgets stays as it is or even decrease over the years. However, at the same time, it is required to maintain road pavements condition at high level. These trends make asset owners and administrators to search for new ways and methods for more efficient roads maintenance management. As the new road is build or old one reconstructed performance indicators should be identified for whole life cycle as it is defined by design. Pavement condition evaluation by indicating present performance indicators level should be done timely and accurate at road level and whole network level. Ongoing support of pavement condition under network level, with a long-term strategy, allows to prolong the life of the pavement, improve traffic safety and meet public expectations. The comprehensive analysis of road maintenance and management systems recommendations for their improvement and application are presented in the article.

The Directive 2008/96/EC of the European Parliament and of the Council of 19 November 2008 on Road Infrastructure Safety Management requires that the Member States shall establish and implement the network safety ranking. Safety performance of existing roads should be increased by targeting investments to the highest accident concentration sections and (or) to the road sections or crossings with the highest accident reduction potential. Road network safety management is applied within the road network in operation covering the selection of traffic safety improvement measures in optimal locations, evaluation of the safety effects and implementing the measures. The article describes the method for selecting and prioritising road sections which have higher than the average accident saving potential in each road category. When selecting road sections for treatment, a potential reduction of accident costs shall be taken into consideration. Road sections in each category are studied and classified by the factors related to road safety, such as the number of accidents, traffic flow and road characteristics. The article describes how the procedure of the road network safety ranking and the ranking of high accident concentration sections is implemented in Lithuania and propose further steps.

The falling weight deflectometer (FWD) is the device most commonly used for the measurement of strength of road pavement structure. Using this device the impact of the wheel of heavy vehicle to the pavement is imitated for the assessment of pavement strength. The stiffness of asphalt pavement layers, as well as E0 modulus values, measured using the FWD, strongly depend on the pavement temperature. When we use deflectometer for measuring asphalt pavement strength at different environmental conditions and in different season the values of E0 modulus should be reduced to the assumed standard temperature. During this research at the experimental asphalt pavement structure the temperature correction factor was revised. The use of this factor enables to reduce the values of the stiffness of asphalt pavement layers measured by the falling weight deflectometer to the standard temperature of +20 °C. In this way the influence of the temperature of asphalt pavement layers upon asphalt stiffness and E0 modulus could be evaluated.

The Lithuanian state road network consists of more than 21,000 km of roads, and gravel roads dominate (43.3%). While the 1998–2000 Paving of Gravel Roads Program was being implemented, there were a few issues in estimating investments that could determine the implementation alternatives of the rehabilitation project. Total costs of renovated gravel roads depended on the climate and geological and hydrological conditions of a location as well as traffic and gravel road characteristics. Roads, like engineering buildings, have to be of sufficient strength and durability, and they should correspond to traffic volume. The results of tests showed diversity of pavements and the characteristics of renovated gravel roads. Gravel roads vary by road width, pavement structure, pavement materials, and traffic. In analyzing traffic on gravel roads, the roads were classified into four groups according to traffic volume. Frequently, the strength of subgrade soils determines the structure of renovated gravel roads. The authors carried out tests on road subgrades under different geomorphologic and geological conditions, estimating the structure, physical conditions, and mechanical properties of these subgrades. According to the test results the strength of existing gravel roads depends on the strength of the subgrade, the thickness of the gravel road, and the quality of the gravel. The equivalent deformation modulus of the gravel roads is described by a binomial. In selecting structures for reconstruction of gravel roads, mathematical models are suggested.

The article presents one of the main parameters of bitumens used for asphalt concrete mixtures production—viscosity. The authors analyse technological ageing process and its influence on viscosity of selected bitumens. Dependence of the viscosity of bitumens on type and amount of the additives, temperature and ageing is described through experiments. Research findings show that the employment of different types of additives increases bitumen viscosity and positively effect the bitumen ageing resistance. Practical application of presented conclusions and recommendations will enable to improve the main characteristics of asphalt concrete pavements and traffic conditions on roads. First Published Online: 26 Jul 2012

Permanent deformation in asphalt pavement structures is one of the main pavement distress problems. The common asphalt pavement surface deformations are shoving and rutting at intersections, bus stops and line, in heavy vehicle loaded urban streets, where it is acceleration, deceleration, slow moving or static loading. Considering the occurred asphalt pavement layer rutting can be described as wear, structural and flow rutting. Recently, was observed the increase in severity and extent of rutting (the depth is 40 mm and more) in asphalt pavement structures in Vilnius city high-streets, bus lines and stops. The purpose of this research was to establish probabilistic (rutted) pavement structures in Vilnius city and to suggest the best treatment solutions. It was found that in many cases the failure was caused by asphalt layers fatigue and low resistance to flow rutting.

The experimental pavement test road section program was carried out in 2007–2013 by the Road Research Institute of Vilnius Gediminas technical university. The road of experimental pavement structures was constructed in 2007 and still continues its operation. The road consists of 27 different pavement structures with the same class of pavement structure, but the different type and composition of materials. The experimental pavement structures were laid on the road to the query, one traffic lane is used by loaded traffic and other – by unloaded traffic. This paper presents the first experimental pavement test road section in Lithuania including pavement design, annual measurements, data acquisition and response analysis. 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) at the end of December 2013 was 480 000.

The rapid growth of heavy traffic, the increase in the standard axle load make scientists to look forward for new durable road constructing materials and their mixes. The continuously increasing need for the strengthening of road pavement structures induces to use new road reconstruction technologies, to search for new methods in constructing pavement structural layers and investigate pavement structures under real conditions. The article presents construction of experimental pavement structures for the first time in the road history of Lithuania. The article also describes the installation process of stress and strain transducers in different layers of experimental pavement structures and initial results of stress and strain measurements. Stress and strain measurements will be carried out each time after passed 20 000 ESAL’s calculated to 100 KN.

Currently there are three pavement management systems (PMS) used in Lithuania for planning and management of road maintenance and repair activities: HDM-III, HDM-4 and DAVASEMA (Lithuanian PMS). HDM pavement deterioration models are used in all of them. With the purpose of calibration and adaptation of those models in 1997 Lithuanian Pavement Deterioration Research Project was developed. The research data gathered in four years of the Project gives an opportunity to draw some conclusions on asphalt pavement deterioration in Lithuania. This article presents the main HDM asphalt pavement deterioration models, and describes the most important steps in adaptation of some input data to those models and calibration of the models to the local conditions. First Published Online: 26 Jul 2012

The article presents three-system modelling of road pavement deterioration used in Lithuania: HDM-III (Highway Design and Maintenance Standards Model), HDM-4 (Highway Development and Management System) and DAVASEMA—Lithuanian pavement management system developed by Lithuanian Road Administration and based on HDM-III models. Using research data gathered in four years of the programme the authors analyse possibilities of adapting the pavement deterioration models to Lithuanian conditions. The article describes suggested procedures for calculating of calibration coefficients for the pavement deterioration models of the highest importance: road roughness component incremental model, structural cracking initiation model and structural cracking progression model. Frist Published Online: 30 Jul 2012

This article deals with the design problems of gravel road pavements. Mathematical models related to geological and hydrological conditions of a location, thickness of gravel pavement and characteristics of the gravel contained in this pavement are proposed to be used for pavements. For the selection of gravel pavements for reconstruction we recommend the models developed by the method of experimental planning to calculate the equivalent deformation modulus of the gravel pavements change depending on the deformation modulus of the subgrade, thickness of the gravel pavement and the materials used for its layers. Practical applications of these models will eliminate the mistakes that are still found in road pavement design. Frist Published Online: 30 Jul 2012

Road traffic noise is one of the largest trend environmental problems, which causes a lot of negative effects to people health and countries’ economies. Road traffic noise abatement and mitigation is a huge challenge for NRAs, which, in the context of decreasing budgets, has not only to maintain sufficient level of their road networks, but also to meet the environmental requirements and society needs. Despite the wide experience of noise reducing asphalt mixtures development and application in European countries, the same effective solution cannot be adapted in all countries because of the regional differences of clime and traffic conditions. For these reasons, Lithuania have started a set of research works related with noise reducing asphalt mixtures development for Lithuanian climate conditions, which could be characterized as a harsh climate conditions with a high number of annual frost-thaw cycles. Article presents laboratory research phase of noise reducing asphalt mixtures. Optimization of traditional asphalt mixtures SMA and AC were performed to increase noise reduction properties at the same time retaining sufficient durability. Conventional and innovative laboratory testing methods were applied. Paper provides results of laboratory testing and analytical analysis of the tested asphalt mixtures properties. Summarized research conclusions and recommendations for further activities are presented in the article.