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Human activities are related to obtain economic, technical, social and environmental benefits. The road construction process participants and road users have direct or indirect benefits from elaboration of new infrastructure. The number of the benefits received by individual entities is publicly discussed by politicians, lobbyists, experts and other decision-makers without having quantitative estimates of benefits, i.e., often relying on intuition or considering theoretical reasoning. The paper suggests a system of 19 benefit entities (criteria) assigned the ranks given by experts. The study involved three categories of experts, including 35 road engineers, 36 transport engineers and 61 road users. The values of the concordance coefficients obtained as a result of the conducted research were found significantly higher than critical values and showed that the opinions of the experts in each category were consistent (not contradictory). This made it possible to consider the average of the opinions of the expert group as a reliable result of solving the problem. Rank averages were replaced by the normalized weights of criteria using Average Rank Transformation into Weight-Linear (ARTIW-L) and – Nonlinear (ARTIW-N) methods. The global averages of criterion weights were used employing the Inverse Hierarchy for Assessment Main Criteria Importance (IHAMCI) method thus calculating the normalized weights of the road-related classified entities (three main criteria). The findings prove that road users benefit the most (weight 0.3485), the road construction contractor (weight 0.3325) is in the next position and the road owner (investor) takes the weight equal to 0.3190. The generated research data can be used for justifying the rationality of road investment.

Slip-form concrete (JPCP) has a number of years of good performance experience. An alternative to slip-form concrete is roller-compacted concrete (RCC). The RCC mixture has a significantly larger number of fine aggregates, which leads the concrete mix to be non-slip and compacted by rollers. RCC has the strength and performance of conventional concrete or even higher. Due to all the advantages, the use of RCC pavement in industrial areas and low-volume rural roads is very beneficial. Experimental test section of RCC pavement structure with cement and special additives stabilized base (CTB) was installed on local road No. 130 in Lithuania, which was reconstructed in 2021. The main objective of this study is to learn about the environmental impact on the pavement structure. To reach our aim at the stage of reconstruction of the local road temperature, humidity sensors and a strain gauge were installed under the RCC layer and CTB. During the lifetime of pavement structure temperature and humidity data were collected daily and bearing capacity was measured during spring thaw. In addition, an artificial wheel load simulation using a falling weight deflectometer was performed at the location of the installed strain gauge to analyse deflections and to calculate stresses under RCC layer. The stresses under the RCC layer calculated from the strain gauge were also compared with the theoretical stress calculated at the design stage of the pavement structure to learn more about performance of the pavement structure. The results showed that slight changes in humidity at the bottom of the CTB had no significant influence on the deformations at the bottom of the RCC layer. Comparison of stresses under RCC layer showed that stresses calculated from strain gauge were 1.80 times lower than those calculated theoretically.

Permeable asphalt pavement is one of the sustainable solutions to remove water from road surfaces. The aim of the research is to analyse the performance of permeable asphalt mixtures depending on the different nominal maximum size and, as a result, to determine the minimum air voids content, which ensures that the asphalt pavement is permeable. To analyse the permeability of asphalt mixtures, ten porous asphalt mixtures with different air voids content and nominal maximum size were designed and tested in terms of air voids content, horizontal and vertical water permeability, water sensitivity, water sensitivity after ultraviolet radiation and mass loss. The results showed that the PA 16 mixture, designed according to the technical requirements TRA ASPHALT 08, was the most porous and permeable mixture, while the modified PA 8 mixture (PA 8_M2) had the lowest air voids content and permeability. Based on the importance of vertical water permeability (0.5%), mass loss (0.3%), water sensitivity (ITSR) (0.2%), the Simple Additive Weighting (SAW) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods showed that PA 11 (0.729 and 0.745) and PA 16 (0.684 and 0.631) had the highest overall weights.

Lithuania’s total road network consists of more than 84000 km of roads, of which more than 21000 km are national roads. Roads of national importance are managed by the Lithuanian Road Administration. The remaining roads are classified as local roads managed by local governments. Road installation and maintenance often lead to the problem of surface water drainage and accumulation on the road surface. The aim of this study is to identify and propose the most appropriate permeable asphalt pavement construction to solve this problem, taking into account the purpose of the application and the class of pavement structure. The scope of the study identifies three recommended permeable asphalt pavement designs for the installation of DK 0.1-DK 1 pavement structures in ancillary streets, parking and recreation areas where light vehicle traffic with occasional heavy vehicle traffic. It has also been found that in areas of high traffic intensity, it is appropriate to use an alternative to permeable pavements – a permeable pavement design for the shoulder, where the roadway structure is impermeable to water and the shoulders are permeable to water (a permeable pavement structure is installed). The recommended permeable asphalt pavement structures, when properly selected, reduce the risk of flooding on the roadway. Article in Lithuanian. Vandeniui pralaidžių asfalto dangos konstrukcijų taikymas transporto eismo zonoms Santrauka Bendrą Lietuvos kelių tinklą sudaro daugiau kaip 84 tūkst. km kelių, iš kurių daugiau kaip 21 tūkst. km yra valstybinės reikšmės keliai. Valstybinės reikšmės kelius patikėjimo teise valdo akcinė bendrovė „Via Lietuva“. Likę keliai priskiriami vietinės reikšmės keliams, kuriuos valdo savivaldos. Įrengiant ir prižiūrint kelius dažnai susiduriama su paviršinių nuotekų nuleidimo ir kaupimosi važiuojamojoje dalyje problema. Šiuo tyrimu siekiama nustatyti ir pasiūlyti šiai problemai spręsti tinkamiausias vandeniui pralaidžias asfalto dangos konstrukcijas atsižvelgiant į taikymo paskirtį ir dangos konstrukcijos klasę. Tyrime nustatytos trys rekomenduojamos vandeniui pralaidžios asfalto dangos konstrukcijos, taikytinos įrengiant DK 0,1–DK 1 klasės dangos konstrukcijas pagalbinėse gatvėse, automobilių stovėjimo ir poilsio aikštelėse, kuriose vyrauja lengvųjų transporto priemonių eismas esant pavieniam sunkiasvorio transporto važiavimui. Taip pat nustatyta, jog didelio eismo intensyvumo vietovėse tikslinga taikyti vandeniui pralaidžioms dangoms alternatyvų sprendinį – vandeniui pralaidžios dangos konstrukcijos kelkraštį, kai važiuojamosios dangos konstrukcija yra nelaidi vandeniui, o kelkraščiai – pralaidūs vandeniui (įrengiama vandeniui pralaidi dangos konstrukcija). Tinkamai pasirinktos rekomenduojamos vandeniui pralaidžios asfalto dangų konstrukcijos sumažina važiuojamosios dalies užtvindymo riziką. Reikšminiai žodžiai: vandeniui pralaidi dangos konstrukcija, asfalto danga, poringasis asfaltas, pralaidumas vandeniui.

Surveying the condition of the pavement is one of the most important processes in managing the road network. The information collected during these surveys allows for the calculation of the Pavement Condition Index, which is a derivative cumulative qualitative indicator that evaluates various pavement characteristics and defects. Deterioration modelling of these measured indicators and calculated indices is a critical element and its most accurate prediction brings the process of pavement management closer to a higher quality process by more efficiently allocating funds and repair work. Many different models – both extremely complex and simple – are used in the world to simulate the condition of individual pavement indicators. However, these models are developed based on the data of a certain country or region and are not suitable in another country due to different requirements for pavement structures and other reasons. In Lithuania, measurements of the quality indicators of road surfaces with new generation survey equipment have been carried out recently but the information stored in the databases about road sections is minimal, and it becomes difficult to adapt the models applied abroad due to the missing information. The aim of this study is to create pavement condition index prediction models by evaluating such quantitative and qualitative indicators as traffic loads, road surface unevenness, type of repair, pavement age, climatic zones, and pavement construction classes.

The performance of unbound base materials, exclusively of the upper base layers, besides compaction level and layer thickness, depends on unbound material type, aggregates shape, fine content and mechanical properties of aggregates. The response of the pavement structure to loading is expressed through stress and strain magnitudes, accumulation of which leads to layer permanent deformations. One of the key factors for designing unbound base layers is resilient modulus, which can be found from triaxial tests. The aim of the research is to analyse the effect of the aggregate particle shape, structure and the resistance to crushing properties on resilient modulus of the upper layers of the unbound base layers. The following properties have been determined during the tests: aggregate particle size distribution, particle shape and flakiness, percentage of crushed and broken particle surfaces, density, water absorption, resilient modulus under low stress level loading. According to the performed research with tested aggregate mixtures, it is assumed that most influence on resilient modulus is exerted by aggregate whole granular size distribution, water absorption and the largest aggregate particle surface angularity. Resilient modulus in the tested dolomite fraction mixtures differing from 32 mm to 56 mm showed any reasonable difference with mean nominal pressures being higher than 300 kPa.

Assurance of asphalt pavement layer compaction, expressed by air voids ratio between field and laboratory bulk density, is one of the main criteria of the asphalt pavement durability. Thus, destructive measures should be applied, and many asphalt samples should be taken on site in order to determine the representative compaction level of constructed pavement. With the fast development of technologies, new methods should be considered for fast, non-destructive and accurate determination of asphalt bulk density on site. As there are quite few non-destructive methods related to asphalt pavement density measurement, there is a need to make comparison of such methods. Currently, when GPR methods are used to determine the density, calibration cores are used in all cases to estimate the unknown or unmeasured variables or conditions that may affect the results of dielectric value measurements. The aim of this study is to develop a regression model that can predict the bulk density of the compacted asphalt layer without coring, using the design values of the bulk density determined in the type tests of asphalt mixtures or other currently used non-destructive testing technologies (in this case PQI and NDG) and GPR measured dielectric constant values.

Managing the condition of the road network is essential to ensure sustainable and efficient road maintenance and development. The term asset management is broad, it describes the actions of infrastructure management – the activities associated with structure maintenance and operation, asset improvement, and development. The article analyzes the impact of the road works on the reduction of Road Roughness Index (IRI) depending on the road type and the type of repair. The annual change in IRI is estimated taking into account certain conditions - pavement structure class, road type, heavy traffic flow, repair type. The research analyzes the data of control assurance protocols of road sections repaired in 2008–2016 and the data of routine pavement performance surveys of the Lithuanian road network conducted in 2019. The results of the research are of considerable practical significance, it is recommended to include them in the repair selection module used by the Lithuanian pavement management system.

Properly designed and maintained asphalt pavements operate for ten to twenty-five years and have to be rehabilitated after that period. Cold in-place recycling has priority over all other rehabilitation methods since it is done without preheating and transportation of reclaimed asphalt pavement. Multiple researches on the performance of cold recycled mixtures have been done; however, it is unclear how the entire pavement structure (cold recycled asphalt pavement overlaid with asphalt mixture) performs depending on binding agents. The main objective of this research was to evaluate the performance of cold in-place recycled asphalt pavements considering binding agents (foamed bitumen in combination with cement or only cement) and figure out which binder leads to the best pavement performance. Three road sections rehabilitated in 2000, 2003, and 2005 were analysed. The performance of the entire pavement structure was evaluated in terms of the International Roughness Index, rut depth, and pavement surface distress in 2013 and 2017.

A considerable amount of literature has been published on municipal solid waste incinerator (MSWI) bottom ash as a substitute for natural road materials. However, most studies are conducted in the laboratory, and as a result, very little is known about the construction of pavement structural layers from MSWI bottom ash mixtures and their performance under real conditions. Therefore, the main objective of this paper is to evaluate the bearing capacity and compaction level of the unbound base and sub-base course constructed from the MSWI bottom ash mixtures. For this purpose, three MSWI bottom ash mixtures (70–100% of MSWI bottom ash) and reference mixtures only from natural aggregates were designed and used to construct the unbound base and sub-base courses on a regional road in Lithuania. In total, five different pavement structures with MSWI bottom ash mixtures and a reference one with natural aggregates were constructed and tested. The results from this study showed that unbound mixtures with 70–100% of MSWI bottom ash are suitable to construct the unbound base and sub-base courses since the bearing capacity of those layers met the requirements (≥80 MPa for the sub-base course and ≥120 MPa for the base course) and was similar to that of the reference pavement (161 MPa for sub-base course and 212 MPa for base course).

This paper presents a case study of driving speed at horizontal curves in the regional road. The literature review of operating speed at horizontal curves in regional roads expresses the difference between design speed and driving speed. Driving speed was measured in ten horizontal curves on regional road No. 2610. Collected data was compared to the design speed, various design standards, and Operating Speed Prediction Models for traffic in low-volume roads. Based on result analysis, was proposed initial adjusted minimum radius of the horizontal curve based on operating speed. It is justified that proposed corrections based on operating speed ensure a credible speed limit effect on road safety. The performed experiment showed different tendencies comparing measured driving speed with permitted and design speeds. It was determined that dependent on specific curved section drivers tend to exceed posted speed limit from 17% to 98% of cases, and from 41% to 100% − the design speed in the horizontal curve. This research led to identifying the limitations of experimental research methodology. These limitations are related to experimental Site selection with different combinations of alignment elements, traffic, and accident data. A pilot study showed significant results and gave essential insights into the full-scale research plan. The results are expected to benefit both other researchers and the organisations responsible for the development and implementation of normative technical documents for road design.

The assurance of asphalt pavement layer compaction, expressed by ratio between field and laboratory bulk density and air voids content, is one of the main criteria of the durability of asphalt road pavement. Destructive measures should be applied and cores should be taken from the asphalt pavement seeking to determine the representative compaction level of the constructed asphalt layers. New methods are constantly being sought for fast, non-destructive and accurate asphalt layer density and air void determination on road. Ground Penetrating Radar (GPR) can allow determining the qualitative characteristics of asphalt pavement across the entire length of the road without causing damage to the road structure. Relative dielectric permittivity, usually called dielectric value or constant, is the leading property used in GPR applications on road pavement surveys. This article presents GPR measurement results from asphalt base and binder layers of four test sections. GPR measurements were conducted immediately after the end of asphalt layer compaction process. Test points on each layer were selected and density, air void content were determined by drilling cores and testing them in the laboratory. To estimate asphalt layer density and air void content, GPR data were analysed using different existing mathematical models. To justify the reliability of the data measured by GPR, results were checked by comparing them with the results measured directly on cores taken from the asphalt pavement layers.

The key factors for effective pavement management system (PMS) are timely preservation and rehabilitation activities, which provide benefit in terms of drivers’ safety, comfort, budget and impact on the environment. In order to reasonably plan the preservation and rehabilitation activities, the pavement performance models are used. The pavement performance models are usually based on damage and distress observations of rural roads, and can be applied to forecast the performance of urban roads. However, the adjustment of the parameters related to traffic volume, speed and load, climate conditions, and maintenance has to be made before adding them to PMS for urban roads. The main objective of this study is to identify the performance indicators and to suggest pavement condition establishment methodology of urban roads in Vilnius. To achieve the objective, the distresses (rut depth and cracks), bearing capacity, and international roughness index (IRI) were measured for fifteen urban roads in service within a two-year period. The distresses, rut depth and IRI were collected with the Road Surface Tester (RST) and bearing capacity of pavement structures were measured with a Falling Weight Deflectometer (FWD). The measured distresses were compared to the threshold values identified in the research. According to the measured data, the combined pavement condition indices using two methodologies were determined, as well as a global condition index for each road. The analysed roads were prioritized for maintenance and rehabilitation in respect to these criteria. Based on the research findings, the recommendations for further pavement condition monitoring and pavement performance model implementation to PMS were highlighted.

The article describes the effiency of polymer-modified road bitumen regeneration with two types of rejuvenators. Two alternative rejuvenators have been selected aromatic oil Nygen 910 and soft road bitumen V12000. PMB 45/80-55 bitumen, which is used in the upper and lower layers of asphalt pavement, was investigated. During the life time of the asphalt pvement, due to the effects of solar UV radiation, temperature and oxygen, of all the layers of the structure asphalt top layer reaches the highest degree of aging. Short-term and long-term aging were performed to simulate the aging of the bitmen under laboratory conditions. To determine the optimal amount of rejuvenator experiments were performed with 8%, 10% ir 14% rejuvenator by bitumen mass. The effect of rejuvenators were evaluated by studying the main physical properties of bitumen: penetration and softening temperature. Ina n experimental study, aromatic oil was found to be more than 2.5 times more effective than soft bitumen. Article in Lithuanian. Atnaujinančiųjų medžiagų poveikis pasendinto polimerais modifikuoto kelių bitumo penetracijai ir minkštėjimo temperatūrai Santrauka Straipsnyje aprašomas polimeru modifikuoto kelių bitumo regeneravimo dviejų rūšių atnaujinančiosiomis medžiagomis efektyvumas. Pasirinktos dvi alternatyvios atnaujinančiosios medžiagos – aromatinė alyva Nygen 910 ir minkštasis kelių bitumas V12000. Tirtas PMB 45/80-55 bitumas, kuris naudojamas asfalto dangos viršutiniuose ir apatiniuose sluoksniuose. Asfalto dangos eksploatacijos metu dėl saulės UV radiacijos, temperatūros ir aplinkos deguonies poveikio asfalto viršutinis sluoksnis pasiekia didžiausią senėjimo laipsnį iš visų konstrukcijos sluoksnių. Bitumo senėjimui laboratorijos sąlygomis imituoti atliktas trumpalaikis ir pagreitintas ilgalaikis sendinimas. Siekiant nustatyti optimalų atnaujinančiosios medžiagos kiekį eksperimentai atlikti su 8 %, 10 % ir 14 % atnaujinančiosios medžiagos nuo bitumo masės. Atnaujinančiųjų medžiagų poveikis vertintas tiriant pagrindines bitumo fizikines savybes: penetraciją ir minkštėjimo temperatūrą. Eksperimentinio tyrimo metu nustatyta, kad aromatinė alyva yra daugiau nei 2,5 karto efektyvesnė nei minkštas bitumas. Reikšminiai žodžiai: asfalto mišinys, atnaujinančiosios medžiagos, bitumas, fizikinės savybės, Nygen 910, regeneravimas, V12000.

Mechanical properties and slab dimensions of concrete are the major parameters based on which the performance of concrete pavement structures is predicted. Precast concrete pavement, as one of the most common modular pavement type, is the advanced next-generation technology characterised as high quality, durable, quickly built and easily maintained. The service conditions of precast concrete pavement (traffic loading and environmental effects) are similar to the conventional cast-in-place jointed plain concrete pavement. Thus, the precast concrete pavement structural design is similar to that of jointed plain concrete pavement. There are several concepts for the design of concrete pavement structure. However, they are based on different distress evaluation and critical stresses estimation methods assuming the slab dimensions that for jointed plain concrete pavement are within the wide joint spacing range from 3.5−6.0 m. The objective of this paper is to analytically evaluate the effect of concrete mixture mechanical properties on the thickness and dimensions of precast concrete pavement slab. Also, define the minimal thickness of precast concrete slab dependent on slab dimensions and concrete mixture mechanical properties elastic modulus and tensile splitting strength. The analysis is based on bearing capacity, performance and fatigue boundary conditions as reported by semi-probabilistic pavement design method Richtlinien für die rechnerische Dimensionierung von Betondecken im Oberbau von Verkehrsflächen RDO Beton 09. Considering that, concrete mixture has significant effects on pavement performance; the composition of concrete was also discussed in this paper. The optimal slab dimensions, concrete layer thickness, and base layer type is suggested in this paper. The outcomes of this analysis apply to the production of precast concrete pavement slabs.

Many roads with asphalt pavement are being reconstructed every year, as their quality becomes insufficient by the requirements. As it is well- known, old roads were built not in the very best quality, so doing reconstruction projects in the most cases there were required to deal with soft soils that are under the existing road structure. Geogrid reinforcement was widely used to solve issues of soft soil in Lithuania. There are projects where geogrid reinforcement is used to control road pavement roughness when there are layers of peat or silt under road structure instead of using concrete piles or geosynthetic-encased soil columns. This type of geogrid reinforcement application is unexplained in any normative-technical document but widely used in Lithuania. This application was usually made constructively without any calculations, choosing the reinforced solution by reducing the geogrid tensile strength or layer quantity compared to reinforced load transfer platform over piles. This paper evaluates the long-term influence of geogrid- reinforced subgrade on the roughness of asphalt surfacing and bearing capacity of the road structure when the soft peaty soils stratify in the deeper layers of the subgrade. There were compared the reinforced sections to adjacent sections to see the effect and fortunately a large number of adjacent sections were also strengthened, mostly by lime stabilisation. Therefore, this comparison allows making more insights on the long-term performance of the strengthened subgrade and influence on the road quality. This research gives recommendations on how the geogrids has to be selected to be used in this kind of application.

Road traffic noise is a widespread problem, especially in the densely populated cities of Europe. Exposure to high levels of (traffic) noise leads to health problems, such as stress, sleep disturbance and even heart diseases. Noise-reducing asphalt pavements are more frequently developed and selected as a first noise abatement solution. Performance of noise-reducing asphalt pavement depends on the composition and properties of asphalt mixture components, and pavement properties such as layer thickness, voids in pavement, texture. Design of asphalt mixture for the noise-reducing asphalt pavements is even more complicated for severe and cold climate regions where significant temperature fluctuations and many of frost-thaw cycles occur. Thus, the balance between mechanical and acoustical durability depends on the proper selection of asphalt mixture components. Components of these asphalt mixtures have primarily to be tested to determine their physical and mechanical properties. The main aim of this research is to evaluate properties of local aggregates, bituminous binders, and regarding test results, select the most suitable materials for the design of high-quality, durable asphalt mixture for noise-reducing asphalt pavements. The research showed that Granite A is the most suitable aggregate for the design of asphalt mixtures for noise-reducing asphalt pavement. Short-term and particularly long-term ageing of polymer modified bituminous binder PMB 45/80-65 and PMB 25/55-60 decreases the number of aromatics and increases the amount of resins. Based on Multiple Stress Creep and Recovery test results, it is assumed that all bituminous binders selected for research are suitable for the asphalt mixture design of noise-reducing asphalt pavement in terms of resistance to rutting. However, considering all tests results, bituminous binder PMB 45/80-65 (1) showed the best performance and was the most suitable for the asphalt mixture design of noise-reducing asphalt pavement.

According to the European Asphalt Pavement Association, more than 90 per cent of the European road network is paved with asphalt. Constantly increasing traffic volume and climate change accelerate deterioration of current pavements. As a result, there arises a need to rehabilitate them prematurely. Repair and rehabilitation work lead to traffic congestion, which is one of the most significant concerns in highly trafficked roads and urban streets. Concrete modular pavements consisting of precast concrete slabs are a reasonable solution to deal with the road works since their construction, as well as repair, is time-saving. Repair works typically are implemented during a low traffic period (usually at night). A primary purpose of concrete modular pavements is heavily trafficked roads and other transport areas. This paper focuses on concrete modular pavements, their types, issues and challenges related to their design, slab fabrication and pavement construction. The conducted analysis revealed 15 different types of concrete modular pavements that differ from the techniques of slab joints and load transfer between the adjacent slabs. More than 20 issues and challenges related to the design of modular elements, slab fabrication and pavement construction were identified. Finally, the existing practice of concrete modular pavements was summarised and the gaps of scientific knowledge, as well as a need for comprehensive research, were defined.

In these days constantly being looking for solution to reduce construction costs, the amount of materials used and the negative impact on the environment. Designing pavement structures with top layer of traditional concrete, the structures become very massive because of variation of concrete thickness from 20 cm to 29 cm according to the standard structures with concrete which are given in KPT SDK 19. An alternative to traditional concrete is roller-compacted concrete, the concrete with significantly larger fine aggregates which lead concrete mix to be non-slip. The roller-compacted mix can also achieve high concrete density and consolidation by rolling. The experimental studies were performed according to the guidelines of the “Guide for rollercompacted concrete pavements” and the automated StreetPave program. Twelve different variants of the pavement structure were used in the calculations, in which the main variables were: the modulus of deformation (Ev2), the thickness of stabilized layer (CTS) and the modulus of elasticity (E). Calculations were also performed for two scenarios, assuming that the amount of cracks appearing on the surface of the top layer after the design period would be 5% and 10%. Article in Lithuanian. Voluojamojo betono taikymas krovininio transporto terminalų aikštelėms Santrauka Nuolatos yra ieškoma sprendimų, kaip sumažinti statybos kaštus, naudojamų medžiagų kiekį bei neigiamą poveikį aplinkai. Be to, nuolatos ieškoma būdų, kaip pritaikyti naujas technologijas ir medžiagas, siekiant paspartinti statybos procesą bei padidinti statinio ilgaamžiškumą. Projektuojant standartines betono dangos konstrukcijas, vadovaujantis KPT SDK 19 taisyklėmis, betono sluoksnis, priklausomai nuo dangos konstrukcijos klasės, kinta nuo 20 cm iki 29 cm. Alternatyva tradiciniam betono dangos konstrukcijos sprendiniui yra voluojamojo betono ant hidrauliškai surišto gruntinio pagrindo dangos konstrukcijos. Tokio tipo betone yra daug didesnė smulkioji užpildo dalis, todėl voluojamojo betono mišinys yra neslankus, o voluojant galima pasiekti didelį betono tankį ir konsolidaciją. Straipsnyje aprašyti eksperimentiniai tyrimai atlikti remiantis „Guide for roller-compacted concrete pavements“ gairėmis bei atliekant skaičiavimus automatizuota StreetPave programa. Eksperimento tikslai – parinkti optimalią voluojamojo betono dangos konstrukciją pagal pasirinktas projektinės apkrovos sąlygas. Skaičiavimuose buvo naudojami dvylika skirtingų dangos konstrukcijų variantų, kuriuose pagrindiniai kintamieji buvo: žemės sankasos deformacijų modulis (Ev2), hidraulinių rišiklių bei jonų mainus gerinančiu priedu sustiprintų gruntų sluoksnio (CTS) storis bei tamprumo modulis (E). Taip pat skaičiavimai atlikti remiantis dviem scenarijais, darant prielaidą, kad po projektinio naudojimo laikotarpio pasireiškusių plyšių kiekis dangos paviršiuje bus 5 % ir 10 %. Reikšminiai žodžiai: betonas, voluojamasis betonas, klotuvas, stabilizavimas.

The article describes the change in the reflection of the horizontal sign examined in the scientific work taking into account the factors of road maintenance and traffic intensity. Methods applied in accordance with the standards in force in the European Union. In order to carry out the study in a smooth way, the scientific work analyzes the horizontal amount of road marking materials, types of markings, the change of reflection in the main traffic conditions. The current legal regulation of Lithuania and other European countries, the USA is also reviewed. “The research work also develops the topic of the effectiveness of the methodology of maintenance and renewal of horizontal road markings abroad and in the Republic of Lithuania.” Recommendations are provided on how to improve the quality of horizontal road marking maintenance. Analyzes of national legislation on horizontal vehicle signs, recommendations on how to improve them to ensure the quality of the production of larger horizontal signs, or the best traffic conditions for all road users. Evaluating the reflectivity of selected streets in dry and wet conditions, making suggestions on how to improve the horizontal reflections of road markings and, at the same time, traffic safety. Article in Lithuanian. Horizontaliojo kelių ir gatvių dangų ženklinimo atspindimojo skaisčio tyrimai Santrauka Straipsnyje aprašomas moksliniame darbe ištirtas horizontaliojo ženklinimo atspindžio pokytis atsižvelgiant į kelių priežiūros ir eismo intensyvumo veiksnius. Tyrimui pritaikyti metodai pagal Europos Sąjungoje galiojančius standartus. Tam, kad tyrimas būtų sklandžiai įgyvendintas, moksliniame darbe analizuojamas kelio horizontaliojo ženklinimo medžiagiškumas, ženklinimo tipai, atspindžio pokytis esant prastoms eismo sąlygoms. Taip pat apžvelgiamas esamas Lietuvos ir kitų Europos šalių, JAV teisinis reglamentavimas. Moksliniame darbe taip pat plėtojama kelio horizontaliojo ženklinimo priežiūros ir atnaujinimo metodikos efektyvumo tema užsienio šalyse ir Lietuvos Respublikoje. Pateikiamos rekomendacijos, kaip būtų galima gerinti horizontaliojo kelio ženklinimo priežiūros kokybę. Atlikus nacionalinių teisės aktų, reglamentuojančių horizontalųjį kelio ženklinimą, analizę, pateikiamos rekomendacijos, kaip juos tobulinti, kad būtų užtikrinta didesnė horizontaliojo ženklinimo kokybė, tai lems geresnes eismo sąlygas visiems eismo dalyviams. Įvertinus pasirinktų gatvių atspindžio rodiklius sausomis ir šlapiomis sąlygomis, pateikiami pasiūlymai, kaip pagerinti kelio horizontaliojo ženklinimo atspindį ir kartu eismo saugumą. Reikšminiai žodžiai: horizontalusis kelių ženklinimas, atspindys dieną, atspindys naktį, eismo saugumas, ženklinimo sistemos.

This paper reviews effect of wax content to performance of bitumen and asphalt pavement. Negative influence of wax content is known from literature reviews, which effects elasticity of binder and causes sensitivity to low temperatures and increases cracking. There is lack information of methods to evaluate wax content in bitumen. This paper presents literature review of variety of wax types, separation wax as saturated hydrocarbons by studying fractional composition and methodology for determination of wax content in bitumen and negatively effect of crystallization. Article in Lithuanian. Vaško kiekio poveikio bitumo ir asfalto dangos funkcionavimui teorinis tyrimas Santrauka Šiame straipsnyje aprašomas vaško kiekio poveikio bitumo ir asfalto dangos funkcionavimui teorinis tyrimas. Iš teorijos yra žinomas neigiamas vaško kiekis, turintis įtakos bitumo elastingumui, kuris lemia jautrumą žemai temperatūrai bei didina trapumą. Tačiau Lietuvoje bei kitose Europos valstybėse stokojama patirties taikant vaško kiekio bitume įvertinimo metodus. Tuo tikslu atlikta mokslinė literatūros analizė siekiant nustatyti vaško bitume rūšis, vaško kaip dalies sočiųjų angliavandenilių išskyrimą, tiriant bitumo komponentinę sudėtį, ir metodus, taikytinus vaško kiekiui bitume bei neigiamam kristalizavimosi poveikiui ištirti. Reikšminiai žodžiai: asfalto danga, bitumas, kristalizavimasis, vaškas.

Operating speed is one of the leading safety risk factors, which increases accident risk and influences accident severity. Speeding is the leading cause of accidents and the most common road traffic offense. The key measures of speed control are educational activities and engineering traffic calming measures. This paper presents an investigation of trapezoidal speed humps – one of the traffic calming measures – and their impact on the driver and the occupants of the vehicle. The level of discomfort to the driver and the occupants, caused by vibrations when the vehicle passes the speed hump, was determined during experimental research. The discomfort level, calculated by three methods, indicated the leading cause of discomfort generated by the analysed trapezoidal speed humps.

In the European Union, more than 140 million tonnes of municipal solid waste is incinerated annually. It generates about 30–40 million tonnes of residues known as municipal solid waste incinerator bottom ash, which is typically landfilled. To deal with growing landfills, there is a need to utilize municipal solid waste incinerator bottom ash as a building material. It has been known that municipal solid waste incinerator bottom ash properties strongly depend on waste composition, which is directly influenced by people’s habits, economic policy, and technologies for metals recovery of bottom ash. Thus, municipal solid waste incinerator bottom ash produced in a specific country or region has primarily to be tested to determine its physical and mechanical properties. The main aim of this study is to determine municipal solid waste incinerator bottom ash physical and mechanical properties (aggregate particle size distribution, water content, oven-dried particle density, loose bulk density, Proctor density, optimal water content, California Bearing Ratio after and before soaking, permeability, Flakiness Index, Shape Index, percentage of crushed and broken surfaces, resistance to fragmentation (Los Angeles coefficient), water absorption and resistance to freezing and thawing). Municipal solid waste in-cinerator bottom ash produced in the waste-to-energy plant in Klaipėda (Lithuania) was used in this research. Ferrous and non-ferrous metals were separated after more than three months of municipal solid waste incinerator bottom ash ageing in the atmosphere. The study showed promising results from considering municipal solid waste incinerator bottom ash as possible aggregates for road building materials.

Usually, C30/37 strength class concrete is used to construct concrete pavements on a rigid, semi-rigid or flexible base. Concrete with such a strength delivers essential design characteristics: flexural strength and tensile splitting strength are between 4.5–5.4 MPa and 2.8–3.7 MPa, respectively. Design characteristics can be significantly increased by densifying the concrete mixture, i.e., adding silica fume, steel or polypropylene macro fibers. As high-performance concrete characteristics are 20–60% higher than those for standard concrete (C30/37), new possibilities to reduce the thickness of concrete pavement slabs appear. The theoretical analysis of concrete pavement structures with high-performance concrete mixtures (C40/50, C45/55 and C50/60) showed that slab thickness could be reduced by 6–39% compared to a standard concrete pavement structure depending on the concrete properties and design method. From all those pavement structures, three concrete mixtures were determined as the most rational ones in terms of PCP thickness reduction and total pavement cost: (i) with 49.5 kg/m3 of steel fibers and 25.2 kg/m3 of silica fume; (ii) with 10.0 kg/m3 of polypropylene fibers (type A); (iii) with 49.5 kg/m3 of steel fibers.

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.

The paper presents an overview of noise propagation mechanisms, wheel–rail interaction models, and the European legislation regulating noise emitted by railway traffic. Acoustic and non-acoustic methods for noise mitigation are described, and their effectiveness is evaluated. Recommendations are given about criteria that can be used for their evaluation so as to ensure the greatest possible level of their compliance with local conditions. The design documentation of Lithuanian international lines is analysed in order to determine noise mitigation measures applied in that region, and to assess their effectiveness.

In the context of increasing traffic demands and emerging mobility trends road infrastructure has to shift towards the fifth generation of roads, which according to Forever Open Road (FOR) vision are envisioned as adaptable to traffic volumes, resilient to changing weather conditions, quickly built, effectively maintained, suitable for retrofitting, self-monitoring, self-repairing and recyclable. Concrete modular pavements can be defined as an example of such type of road infrastructure. Functional needs are mainly associated with implementation area/location, traffic and mobility demands, environmental constraints and etc. This also has a significant impact on the selection of Precast Concrete Pavements (PCP) texture formation method and materials. Concrete pavement surface texture affects both safety and tyre/road noise characteristics. Exposed Aggregate Concrete (EAC) and porous concrete are the most suitable noise reducing solutions for highways and streets wearing layer even in severe traffic and climate conditions. According to the literature analysis, the algorithm of highways and streets low noise concrete design was created. It is recommended to use the highest quality aggregates with maximum size up to 8 mm, gap-graded gradation, higher amount of cement and lower water/cement ratio. The most important characteristics of EAC are Mean Profile Depth (MPD), Mean Texture Depth (MTD) and profile count, while the most important characteristics of porous concrete are compressive strength, outflow and air void content.

This paper presents a performance of the open-graded asphalt concrete filled with a special cement grout in the road structures, introduces practical examples of the usage of this technology and defines the main properties. In addition, laboratory design of asphalt mixtures filled with special grout is researched. Finally, the results obtained from various laboratory tests are evaluated. The paper contains the open-graded asphalt concrete filled with a special cement grout mix design procedure and results of stiffness measurement, low temperature properties, permanent deformation and skid resistance. Open-graded asphalt concrete filled with a special cement grout mixture is compared to the commonly used asphalt mixes. The open-graded asphalt concrete filled with a special cement grout showed better results than the commonly used asphalt mixes by the stiffness and resistance to the permanent deformation characteristics but behavior at the low temperatures is slightly problematic.

The optimum density and air-voids content of asphalt pavement layers are among the main indicators of the durability of asphalt road pavement. The asphalt pavement with insufficient density is less resistant to traffic loading and the damaging effects caused by water. Air-voids ensure the durability of asphalt pavement and the accumulation of free bitumen during a period of hot weather. At present, the main ways to control the quality of compaction and the content of air-voids is to drill core specimens and test them in the laboratory. This method is expensive, it damages the road surface, and the quality of asphalt pavement is verified only at several points. With the rapid development of new technologies, it is necessary to evaluate and to apply innovative non-destructive methods, allowing us to determine the qualitative characteristics of asphalt pavement across the entire length of the road without causing the damage to the road surface and at lower costs. This article describes the use of Ground Penetrating Radar to determine asphalt pavement density and air-voids content provides an overview of global practices and feasibility analysis on the application of Ground Penetrating Radar on the roads of Lithuanian. Santrauka Asfalto dangos sluoksnių optimalus tankis ir oro tuštymių kiekis yra vieni iš pagrindinių dangos ilgaamžiškumo rodiklių. Nepakankamo tankio danga yra mažiau atspari automobilių eismo apkrovoms ir žalingam vandens poveikiui. Oro tuštymės užtikrina dangos ilgaamžiškumą ir laisvojo bitumo akumuliavimą karštuoju metų laikotarpiu. Šiuo metu pagrindinis būdas kontroliuoti sutankinimą ir oro tuštymių kiekį yra gręžti kernus ir juos bandyti laboratorijoje. Šis metodas yra brangus, gadinama kelio danga ir asfalto dangos kokybė patikrinama tik keliuose taškuose. Sparčiai vystantis technologijoms būtina įvertinti ir taikyti inovatyvius neardančiuosius metodus, leidžiančius kokybinius asfalto dangos rodiklius nustatyti neardant dangos, išilgai viso kelio ir mažesnėmis sąnaudomis. Šiame straipsnyje pateikta georadaro (angl. Ground Penetrating Radar) taikymo asfalto dangai sutankinti ir oro tuštymių kiekiui nustatyti pasaulinės praktikos apžvalga ir panaudojimo Lietuvos automobilių keliuose galimybių analizė. Reikšminiai žodžiai: asfalto danga, didžiausias tankis, georadaras (GPR), oro tuštymių kiekis, sutankinimas, tariamasis tankis.

This article analyses the influence of properties of frost-susceptible layers on water permeability functionality. It is necessary to ensure adequate water permeability of the structural layers and control of groundwater level to prevent or at least reduce the deformation of the road surface. Particularly important factors for proper water permeability are: the particle size distribution, composition of the mineral aggregates mixtures or used soil, their contamination, the degree of saturation and the number of air voids in the layers, the density of the layers. The test for determination of the water permeability coefficient is based on the Darcy law, which states that water permeability (also known as hydraulic permeability) is equal to the pressure variation over a body of a certain length. In geotechnical engineering, the water permeability of the mineral aggregates or soils is determined using a constant headwater permeability apparatus. It is necessary to take into account the fraction of the test object and perform the test at different hydraulic ramps to assess the suitability of the results. An experimental laboratory test plan was developed. Santrauka Šiame straipsnyje analizuojama šalčiui nejautrių, atsparių sluoksnių bei žemės sankasos gruntų savybių įtaka pralaidumo vandeniui funkcionalumui. Siekiant išvengti ar bent sumažinti dangos paviršiaus deformacijas, būtina užtikrinti pakankamą konstrukcijos sluoksnių pralaidumą vandeniui ir gruntinio vandens lygio kontrolę. Itin svarbūs rodikliai tinkamam vandens pralaidumui yra naudojamų mineralinių medžiagų mišinių ar gruntų granuliometrinė sudėtis, jų užterštumas, soties laipsnis ir oro tuštymių kiekis sluoksniuose, sluoksnių tankiai. Pralaidumo vandeniui koeficiento nustatymo bandymas remiasi Darsi (angl. Darcy) dėsniu, kuris teigia, jog pralaidumas vandeniui (taip pat žinomas kaip hidraulinis pralaidumas) yra lygus slėgių pokyčiui per tam tikro ilgio kūną. Tradiciškai geotechninėje inžinerijoje gruntų ir mineralinių medžiagų įsotintos medžiagos pralaidumas vandeniui nustatomas naudojant pastovaus spūdžio pralaidumo vandeniui koeficiento nustatymo įrangą. Bandymo metu nustatomas pratekėjusio vandens kiekis per tam tikrą laiko tarpą. Siekiant įvertinti rezultatų tinkamumą, būtina atsižvelgti į bandomojo objekto frakciją ir atlikti bandymą esant skirtingiems hidrauliniams nuolydžiams. Sudarytas eksperimentinio laboratorinio tyrimo planas. Reikšminiai žodžiai: apsauginis, šalčiui atsparus sluoksnis, dangos konstrukcija, granuliometrinė sudėtis, hidraulinis nuolydis, pralaidumas vandeniui, pralaidumo vandeniui koeficientas, sutankinimo rodiklis, oro tuštymės.

The quality of road bitumen in asphalt mixtures is one of the most important factors affecting performance of the entire pavement structure during its service. In particular, the type and refining technology of the crude oil are the most significant aspects influencing bitumen properties. As the same time it is still necessary to assess other aspects that contribute to the changes in bitumen properties, such as bitumen aging during asphalt mixing, storage, transportation, laying and a gradually increasing oxidation in asphalt pavement structure during pavement service life. Bitumen originating from different producers and supplied to Lithuanian market satisfies the requirements of European standards concerning the basic physical properties, albeit certain instability processes in bitumen properties can be observed: bitumen is more liquid and less sticky at a laying temperature; reduced cohesion, increased cracking during compaction; reduced adhesion between bitumen and mineral materials; changes in perceptible properties (odour, colour), and others. These observations have led to numerous discussions on the potential ways of improving bitumen quality, selection of proper methods for bitumen quality assessment and determination of the recommended threshold values. The objective of this paper is to demonstrate the effect of bitumen chemical composition and associated structure on asphalt pavement performance. Performance was expressed in terms of susceptibility to rutting measured by the Performance Grade system developed in the US. Based on the results obtained during this experimental study the limit values of bitumen fractional composition were identified.

Pavements of aprons, container and logistic terminals, areas of storage, parking lots, areas of waste utilization are affected by high pressure static and impact loads. These loads strongly influence pavement performance by causing permanent deformations and distresses in the surface and even sometimes pavement failure in the beginning of pavement service. The types of structure, materials and layer thicknesses are the main factors relative to pavement performance. In order to correctly understand the particularity of static and impact loading, distresses of pavement structures affected by such load are emphasized, the load specification and climatic conditions influencing pavement performance are characterized. After analysis of the best practise, the flow chart of pavement structure design model was introduced. The paper gives reasonable pavement type and thickness determination dependent on object of application pavement structure.

As the railway lifespan is the main criterion for selection of the aggregate for ballast and for planning the maintenance of the railroad, it is important to define the relationship between the particle load resistant characteristics and a lifetime of ballast in structure. Assessment of the quality of the ballast aggregate particles under dynamic and static loading reflect both, the toughness and hardness, and these are identified with the Los Angeles Abrasion and Micro-Deval Abrasion values. The model formerly developed by Canadian Pacific Railroads was adapted to predict possible loads expressed in cumulated tonnes. Different ballast aggregate mixtures were tested in the laboratory including dolomite and granite. Calculated potential gross tonnage (expressed in Million Gross Tonnes) of the railway per lifetime for each different aggregate type presented. The outcome of this research is established classification system of railway ballast aggregate and defined Los Angeles Abrasion and Micro-Deval Abrasion values of aggregate dependently on required lifetime.

In cold regions and areas where there is a huge difference between high and low temperatures asphalt pavements are subject to low temperature cracking. The appeared cracks form pavement discontinuities, through which water penetrates into pavement structure. It reduces the bearing capacity of the whole pavement structure, weakens adhesion between bitumen and aggregate, affects bonding between layers and increases the development of frost heaves. A sealing of cracks deals with these issues. However, additional inspections after each winter have to be carried out to identify both cracks that have newly appeared and cracks that need to be resealed. These activities significantly increase road maintenance cost. Selection of the appropriate asphalt mixture by its performance at low temperatures reduces or even prevents low temperature cracking of asphalt pavements. A number of methods such as the Indirect Tensile Test, the Bending Beam Rheometer Test, the Thermal Stress Restrained Specimen Test, Asphalt Thermal Cracking Analyser, the Single-Edge-Notched Beam Test, the Disc-Shaped Compact Tension Test, the Semi-Circular Bend Test, the Fenix Test, Asphalt Concrete Cracking Device and Spectral Analysis of Acoustic Emission are developed to evaluate asphalt mixture resistance to low temperature cracking. This paper presents an analysis of these tests, emphasizes their advantages and disadvantages and gives limiting criteria to evaluate asphalt mixture resistance to low temperature cracking. The test advantages and disadvantages are deciding factors in a test selection. Some tests such as the Thermal Stress Restrained Specimen Test and Spectral Analysis of acoustic emission can directly reveal the lowest temperature at which asphalt mixture can withstand induced thermal stresses.

Accidents are one of the leading cause of death all over the world. Speed has been identified as a factor in road accidents, influencing both the risk of accidents and the severity of the accidents. However, speeding is one of the most frequent violations of traffic rules by the road users. Many results of studies showed that the implementation of speed cameras significantly reduced the vehicle speed and the number of accidents near camera sites. One issue regarding speed enforcement by a speed camera is that a reduction in speed is obtained only on a short section of a road. The results of scientific research analysis suggest that this issue can be overcome by the employment of average speed enforcement system (hereafter system), which is a relatively new approach to traffic law enforcement. Until now, Lithuania had no methodology for selecting road sections to be installed with the system. The purpose of this paper is to develop a model for the assessment of safety impact of the system and to perform economic estimation of a system of Lithuanian main road sections selected under this model. The analysis of international practice helped to develop this model, which joins accident indicators, road and traffic parameters. A cost-benefit analysis of the system, implemented on main road sections and selected by suggested model, shows a high level of payback. The implementation of the system would pay back in one year of service.

The paper gives a detailed overview and analysis of road transport noise propagation, noise composition and impacts on the living conditions. Road transport noise has been rapidly growing and the traditional noise abatement solutions, such as noise barriers, are not always suitable and cost-effective for particular road infrastructure. One of the most promising and effective solutions is the use of low noise pavements. Presently, low noise pavements are not being used in Lithuania but expected to have a good environmental noise reduction potential. However, the most effective low noise pavement solutions according to other European countries’ experience are not always applicable for Lithuanian road conditions. For these reasons, few low noise asphalt pavement mixtures were developed to achieve a relatively high noise reduction effect and maintain sufficient mechanical and operational characteristics under Lithuanian conditions. Laboratory testing results (including mechanical and physical, noise reduction and durability characteristics) and comparison with traditional asphalt mixtures are provided in the paper as well as recommendations for the use of the developed low noise asphalt mixtures.

The increased use of geosynthetics in road constructions has resulted in a need to better understanding of geosynthetics properties for the use in design and quality control. For this purpose, the regulations for use of geosynthetics for road embankments and subgrades were created in Lithuania. It was found that other European countries such as Germany and United Kingdom use not only harmonised European standards, but also has their own regulations for geosynthetics. This study indicates the relationship between regulations in Lithuania and other countries. Calculation conception and regulations for controlling characteristics were introduced first time in Lithuanian road construction market. The use of those regulations will increase the quality of construction and life time of road pavement structures.

This paper presents the elements of a Pavement Management System with a particular focus on the initial effort to create a comprehensive data archive and its further application in four different maintenance strategies. Pavement performance indicators including longitudinal and transverse cracking as well as roughness were investigated with respect to numerous distinct factors which can be grouped into three categories, i.e. climatic, pavement structure, and traffic-related. High-quality climatic data was obtained from the national weather stations in Connecticut. Maintenance and construction data was used to determine the pavement age and structure amongst several other factors. Traffic data was acquired from the state records and accumulated traffic loading was estimated for all segments based on their age. High definition pavement images collected by the Automatic Road Analyzer vehicle in 2010 were used to quantify the longitudinal and transverse cracking with respect to their location within the pavement surface. Elements of the Pavement Management System with stochastic elements were created from this data and analyzed in order to demonstrate the budget implications under four different management scenarios. Scenarios varied by the trigger values of the Pavement Condition Index for considered maintenance treatments. The 20-year projection analysis clearly showed the benefit of repairing pavements that are still in a good condition even without considering related user-delay costs and/or vehicle-operation costs which would only heighten the differences between scenarios.

Even though every layer of pavement structure is important and affects pavement performance, the asphalt layers visco-elasticity plays significant role. Bitumen properties, as well as asphalt mixture properties, vary depending on temperature and loading conditions. These variations influence entire pavement bearing capacity and has to be evaluated in pavement design. The main challenge is material behaviour description through simple models to incorporate them to pavement design. Generally, pavements are designed using Multilayer Elastic Theory assuming that all materials are elastic, isotropic, and homogenous. This paper presents analysis of two pavement structures response calculated according to three pavement design approaches. The dynamic modulus and phase angle of asphalt mixtures was estimated using Hirsch model after binder complex shear modulus tests. The visco-elastic behaviour was described with rheological Huet-Sayegh model and pavement responses estimation was done using MnLayer and ViscoRoute2 software. The analysis reviled static and dynamic load influence on pavement structure based on elastic and visco-elastic properties of asphalt layers. This allowed optimisation of layer thicknesses and determination of more cost beneficial pavement structure with appropriate performance.

Environmental conditions (temperature, moisture and the intensity of the sun) influence variation in asphalt pavement strength during the year. Lithuania is situated in a zone by average warm summers and average cold winters, and the most important climatic factor is the variation of the air temperature. This study presents the influence of temperature (of asphalt concrete (AC) and subgrade layers) and moisture content (of subgrade layers) to the pavement bearing capacity. The experimental research was obtained in five pavement sections of the experimental road. This experimental road was constructed in 2007 in Lithuania and is operated for more than 12 years. This paper presents a statistical analysis between the bearing capacity and the thickness of the asphalt concrete layers, the temperature and moisture content of different pavement layers, among sections, loaded and unloaded lanes (right and left wheel paths and tracks). The bearing capacity was evaluated by a falling weight deflectometer (FWD), temperature and moisture content by electronic sensors and thickness of AC layers by Georadar. Analysis of overall E0 and E0,h9 (bearing capacity at a depth of 9 cm from asphalt surface) data declares that seasonal impact on pavement structural strength due to a change of subgrade bearing capacity remains after correction of asphalt stiffness dependent on the temperature in the layer. However, it was detected that neither E0 nor E0,h9 are related to moisture content at a depths of 100 cm, 130 cm and 150 cm.

High value of traffic flow influenced the need to build long lasting pavement structures with design life of more than 20–40 years. Current budget for maintenance and reconstruction is not sufficient for preventing the rutting on the existing asphalt pavement roads and streets. These factors lead to search for new materials, mixtures, and methods for preparation of asphalt mixes. The high modulus asphalt concrete is regarded as one of possible solutions. The laboratory study of the high modulus asphalt concrete with different types of bitumen binder and mineral aggregates is presented in the paper.

The strength and durability of road pavement structures are directly influenced by the way in which asphalt layers are bonded. An insufficient bond between pavement layers leads to wearing, tearing, pavement deterioration, and cracking, and the pavement life span is reduced. The quality of bond between pavement layers was determined by direct shear test, using the so called Leutner method, without normal stress in specimen. Test samples were taken at various locations along the Lithuanian road network, from pavements characterized by standard asphalt structure, and reinforced asphalt structure in which geosynthetic materials are used in interlayers.

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.

One of the biggest problems of constantly growing transport sector is traffic safety. Innovative technologies are an effective tool to deal with the following issue. In order to ensure efficient and coordinated development of intelligent transport systems, it is essential to know their individual performance and impact on traffic safety. This article gives the summary of the effect of intelligent transport systems on road traffic safety. The aim of the research is to highlight intelligent transport systems and intelligent transport systems applications which have the greatest positive impact on traffic safety. To achieve this aim, meta-analysis of previous studies and analysis of experts interviews was carried out. The research consider the following thirteen driver support and control systems regarding their potentials to reduce the number of fatalities: average speed control system, stationary speed cameras, “Alcolock” ‒ application of drunk driver detection, “eCall” system, variable speed limit sign, red light violation detection cameras, forbidden maneuver detection system, vehicle identification system, variable message boards, intelligent road studs, incident detection system, weigh-in-motion system and seat belt control system.

Gravel roads play an important role in the transport infrastructure. However, their maintenance (especially the control of dustiness using chemical dust suppressants) is expensive. Besides, the condition of gravel roads results in low driving comfort, longer travelling time, faster vehicle amortization, and so forth. Typically, these problems are solved by paving gravel roads with asphalt wearing layer. However, north countries practice had shown pavement structure high susceptibility to frost due to insufficient thickness of frost resistance layer. The construction of thicker frost resistant layer increases road construction cost by 25% and, in most cases, there is no need to increase bearing capacity by increasing total thickness of pavement structure. In 2012 19 gravel roads were constructed using cost effective rehabilitation technologies—soft asphalt and double Otta Seal in Lithuania. This paper focuses on those two technologies’ performance within first three years of constructed roads exploitation. The implemented experimental research consisted of three parts by evaluating constructed roads base layers bearing capacity; pavement roughness; and pavement distresses and defects. As a result, the acceptable performance indicators were determined for both technologies—soft asphalt and double Otta Seal. Also recommendations for construction and exploitation improvement were defined.

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. In May, 2012 totally 320 000 ESAL’s (100 kN) passed the road. Annually – about 70 000 ESAL’s. This article gives the research results of the bearing capacity and surface characteristics of experimental pavement structures after five years of their service.

Resistance to frost of road pavement structure is ensured by a functional frost blanket course from frost nonsusceptible soils or aggregate mixtures. The material used and the thickness of frost blanket course must not only ensure the required resistance to frost of road pavement structure but also to increase bearing capacity of the structure, to distribute and reduce pressure to the subgrade surface. The article gives a summary of research on aggregates mixtures and soils used for a frost blanket course and taken from the currently operating quarries in Lithuania. The conclusion of research analysis gives the suggestions for the use of materials for a frost blanket course. Based on the data obtained it is recommended when laying a frost blanket course to take into consideration bulk density and Proctor density of the material used as well as transportation costs.

The data were collected by researchers at the Road Research Institute, in a study investigating the impact of differentfactors on road surface strength. In this statistical analysis, we apply linear mixed models (LMMs) to clustered longitudinal data, inwhich the units of analysis (points in the road) are nested within clusters (sample of four different road segments), and repeatedmeasures of road strength in these different points are collected over time with unequally spaced time intervals. The data arebalanced – each cluster has the same number of units, which are measured at the same number of time points. Because of correlateddata and different clusters in which data could be correlated, linear regression models are not appropriate here, and therefore linearmixed models are applied.