Hasil untuk "Highway engineering. Roads and pavements"

Chaohui Wang, Tonghao Zhang, Anquan Li et al.

To reduce the temperature diseases of asphalt pavement, improve the service quality of road and extend service life, the research of inorganic powders that reduce the temperature of asphalt pavements was systematically sorted out. The common types, physicochemical properties and application methods of inorganic powders were defined. The road performances of modified asphalt and its mixture were evaluated. The modification mechanism of inorganic powders in asphalt was analyzed. On this basis, the cooling effect and cooling mechanism of inorganic powders was revealed. The results indicate that inorganic powders are classified into hollow, porous, and energy conversion types. The high-temperature performance of inorganic powders modified asphalt and its mixture is significantly improved, while there is no significant change in low-temperature performance and water stability. The average increase in rutting resistance factor (G∗/sin(δ)) and dynamic stability is 40%–72% and 30%–50%, respectively. The modification mechanism of inorganic powders in asphalt is physical blending. The thermal conductivity of hollow and porous inorganic powders modified asphalt mixture decreases by 30.05% and 43.14%, respectively. The temperature of hollow, porous and energy conversion inorganic powders modified asphalt mixture at 5 ​cm decreases by 2.3 °C–3.5 ​°C, 0.8 °C–3.7 ​°C and 4.1 °C–4.7 °C, respectively. Hollow and porous inorganic powders block heat conduction, while energy conversion inorganic powders achieve cooling through their functional properties.

Piotr Wrzecioniarz, Karol Mierzwa, Dominik Liśkiewicz et al.

Abstract: On the basis of previous own designs of Hyperloop system for Earth conditions, the concept of this type of transportation for the Moon and Mars was proposed. The basic technical parameters presented and discussed at the IAC conferences in Dubai are given, demonstrating the high technological readiness of the project. Keywords: Hyperloop; Moon; Mars

Hamad Bin Muslim, Syed Waqar Haider, Lev Khazanovich

Longitudinal joint construction quality is critical to the life of flexible pavements. Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies. Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance. Current quality control (QC) and quality assurance (QA) plans provide limited coverage. Consequently, the risk of missing areas with poor joint compaction is significant. A density profiling system (DPS) is a non-destructive alternative to conventional destructive evaluation methods. It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics. The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality. The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint. The paper proposes a dielectric-based longitudinal joint quality index (LJQI) to evaluate the relative compaction of the joint during construction. It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints, identify locations of poor quality during construction, and achieve better-performing flexible pavements.

Serhii Holovko

Introduction. The study considers the issue of technical and economic analysis of alternative design options of non-rigid pavement. This issue is especially relevant during the repairing and reconstruction of roads, when it is need to consider the reuse of road construction materials, the use of geosynthetic materials, and so on. Problem statement. Experience shows that most designers perform technical and economic analysis by one indicator only- the estimated cost, which is due to the lack of methodology for technical and economic analysis of such technical solutions. In many countries, the concept of TBL (Triple bottom line) has been implemented in recent decades, when solutions are analyzed in three independent areas, in construction this approach is often formulated as “Three E” concept (economics, energy and environment). Purpose. To develop a method of multifactor technical and economic analysis of alternative design options of non-rigid pavement. Methods of study. According to the results of exploratory researches, it is proposed to apply the method of analysis of hierarchies. Results. According to the problem ststement, a hierarchical system for determination of the optimal design option of non-rigid pavement is developed. According to the developed hierarchical system, the vectors of priorities of independent factors of analysis are determined, which allow to evaluate objectively the designed alternative options. The searching for the best option is performing by independent factors based on the analysis of economic, energy and environmental indicators. Conclusions. Performed modeling using the method of hierarchy analysis allows to make a multifactor analysis of alternative options of non-rigid pavement with the definition of the optimal design.

Jorge Alberto Vasquez Rodriguez

La reorientación de la política pública de la infraestructura vial nacional de 1998 incorporó aspectos claves del Nuevo Estilo Nacional de Desarrollo vigente en el país en el momento de su oficialización. Este estilo desde principios de los años 80 promulga el protagonismo del mercado, en deterioro del papel del Estado, de ahí, que concordante con el mismo se trasladó la construcción, conservación y mantenimiento de la Red Vial Nacional del Estado al empresario privado, mediante contrataciones administrativas a cargo de un ente público denominado el Consejo Nacional de Vialidad, en donde en su consejo de administración, máximo jerarca de esa institución, estarían incorporados tres miembros de los empresarios organizados del mercado de la construcción de carreteras, con voz y voto, que coadministrarían la institución, con otros tres miembros representantes del gobierno de turno y uno de los gobiernos locales, con recursos provenientes de un Fondo Vial Nacional. La formulación de la política presenta un déficit de formulación, generada principalmente por la reformulación del problema público y de la estrategia de intervención de la política pública, generada desde “lo político” en la Asamblea Legislativa en el primer cuatrimestre de 1998, de ahí, que no se le brindó una posible respuesta a algunas de las causas del problema público como la relocalización de servicios, las expropiaciones, la coordinación con entes públicos que determinan el avance de la obra vial, la protección del medio ambiente, el control y calidad de las carreteras, el control excesivo sobre las obras viales, ejercidos directamente o indirectamente por entes públicos controladores, generándose así un déficit de formulación en la política pública, que incide negativamente en los resultados de la misma

Mahdi Asadi, Fouad Kilanehei, Amir Mahjoob

This paper investigates the effect of different geometries of approach embankments and guides banks on the flow pattern and bed shear stress values in the skewed bridges in the compound channel using three-dimensional numerical modelling. First, the numerical model was evaluated based on the results of existing laboratory studies. After ensuring its proper performance, the elliptical guide bank and the three types of abutments: vertical-wall, spill-through, and wing-wall, at different skew angles are examined. Investigation of the values of maximum velocity and bed shear stress at the flow-conducting embankment and the flow-splitting embankment showed that in the flow-conducting embankment, the best performance is assigned to the elliptical guide bank. In contrast, the performance of various abutments is different for the flow-splitting embankment depending on the skew angle of the bridge. Then, different patterns based on streamlines for the geometry plan of the guide bank were proposed and studied. The results show that the most suitable pattern for the guide bank reduces the maximum flow velocity by up to 15% and reduces the maximum bed shear stress by up to 80% around the flow-splitting embankments.

Piotr Nita, Małgorzata Linek

Abstract: The intensification of air operations in recent years has resulted in an increase in stresses and deformations in concrete pavements. In terms of mass, dynamic and temperature interactions, these are measurable phenomena that can be determined and predicted using appropriate methods and algorithms. Another type of impact that does not occur in an avalanche-like manner on pavements is their random destruction caused by the presence and operation of exploitation media. The article presents the impact of selected measures on the change of concrete parameters and its durability in the pavement structure. The effects of this impact are significant and clearly destructive for concrete pavements. In addition to the measurable decrease in the mechanical parameters of concrete, there is an interference of media with the concrete structure, which in the presence of extreme temperatures (positive and negative) is a challenge for concrete technologists, contractors and users of airport pavements. The nature of the impact of exploitation media is varied and in most cases there is a combined effect of them on pavements. It has been shown that the operational coatings currently applied to pavements are only partially effective for these media, and learning about the nature and manner of impact makes it possible to effectively limit these unfavorable, objectively occurring phenomena. Keywords: Concrete airport pavement; Operating media

Xin Jiang, Yongguo Fu, Linyu Li et al.

In this paper, the typical cases of subgrade separated widening project in China are summarised. The research progress of subgrade separated widening and isolating wall applications are reviewed in highway reconstruction and extension. A numerical model is established based on the PLAXIS finite element software, considering both material nonlinearity and geometric nonlinearity. The effect mechanism of the isolating wall is discussed on the settlement control of the new and existing embankment on soft ground. The effect rule of the core design parameters of the isolating wall is revealed on the settlement disturbance of the existing embankment, such as location, depth, thickness and elastic modulus, and the weight rank of the influence is analysed. The results indicate that the isolating wall effectively reduces the lateral displacement and vertical settlement of the existing embankment, and there is an optimal design location for the isolating wall. In addition, with the increase of design parameters of the isolating wall, including depth, thickness and elastic modulus, the overall settlement of the existing embankment tends to be uniform, and there are optimal values. Furthermore, the depth of isolating wall is given priority, compared to location, thickness and elastic modulus during the isolating wall design process. The research results lay a theoretical foundation for the design optimisation of the isolating wall in the separated widening project of soft ground.

Nuroji, Sukamta, Nicolaus Iyowau

Bambu merupakan tanaman jenis rumput-rumputan yang mudah tumbuh dengan waktu pertumbuhan yang relatif cepat dan dapat dipanen pada usia 3-4 tahun tanpa harus menanam ulang. Meskipun bambu mempunyai sifat fisik dan mekanik yang baik, tetapi pemanfaatan bambu sebagai material konstruksi masih sangat terbatas. Pengembangan material bambu sebagai material konstruksi diharapkan dapat mereduksi penggunaan kayu yang selama ini telah dieksploitasi secara masif. Paper ini menjelaskan hasil kajian eksperimental material bambu dan papan bambu lapis. Papan bambu lapis tersusun atas tiga layer dan setiap layer terbentuk atas bilah-bilah bambu yang tersusun secara paralel. Layer 1 dan 3 merupakan layer permukaan dengan arah memanjang papan, sedangkan layer 2 merupakan bagian tengah papan yang membentuk sudut a terhadap layer 1 dan 3 yaitu 30°, 45° dan 90°.  Hasil pengujian tarik menunjukkan bahwa semua bilah bambu berperilaku getas, bagian luar mempunyai kekuatan dan kekakuan yang lebih tinggi dibanding bagian dalam dan ruas bambu merupakan perlemahan dari bilah bambu. Pengujian lentur papan bambu lapis dilakukan dengan four point bending, kapasitas dan kekakuan papan bambu lapis dipengaruhi oleh sudut a dengan nilai optimal 29,33°. Sedangkan kekakuan lentur rata-rata papan bambu lapis sebesar 71% dari penampang teoritis dengan dimensi yang sama untuk bilah bambu luar.

Stoeck, Tomasz

The article presents the problem of implementation sharing economy services in relation to the urban transport system. Basic information related to this concept and the principle of its operation was discussed, with particular emphasis on economic, ecological and social aspects. The analysis considered the growing role of unmanned rental shops of various types, whose development and functioning influences the change in communication preferences of Szczecin residents. The research part compares travel times of available vehicles on a selected test section. The presented conclusions and observations can be helpful in modernizing current or implementing completely new initiatives in the field of providing modern means of transport. They are to guarantee public availability in a precisely defined area and a relatively short time of use, and at the same time be adapted to the needs of a given agglomeration. Keywords: Sharing services; Urban transport; Communication preferences

Saverio Olita, Maurizio Diomedi, Donato Ciampa

The design of rigid pavements is historically based on the classical Theory of proposed by Westergaard in 1929, which considers the rigid pavement as a thin plate resting on an elastic ground with a Winkler reaction, imposing the congruence of vertical displacements at the points of contact between the pavement structure and the ground. Westergaard’s Theory provides expressions for the calculation of maximum stress in concrete slabs for interior, edge and corner load conditions. This work focuses on the development of a Finite Element model, implemented in the ANSYS® environment and calibrated on the basis of the results of the in-scale experimental model developed by Lall and Lees in 1983. The implementation of the FE model was performed through a set of steps capable of reproducing physical and mechanical conditions of the true model, which was further intended to be used for numerical analysis. After the FE model was developed, it was possible to carry out multiple simulations pursuing three main aims: to evaluate the effect of the variation of material properties on the slab stress state, to compare the maximum stresses for the interior and edge load conditions considering Westergaard’s Theory, the experimental data and the results of the numerical model, and to use the developed and calibrated model to formulate an alternative mathematical expression, which would allow calculating the stress in corner load conditions.

Adriana de Jesús García

Las recientes teorías clasifican el asfalto como una matriz continua, donde asociaciones de moléculas polares (asfaltenos y resinas) se dispersan en un fluido de moléculas de menor peso molecular y polaridad (aromáticos y saturados). Para entender mejor el comportamiento del asfalto se realizó una revisión de literatura, donde se pudo observar que la metodología más innovadora es la aplicación del microscopio de fuerza atómica, el cual permite caracterizar los materiales a escala nanomecánicas. La técnica del AFM se ha venido utilizando en los últimos 20 años, como una de las herramientas que combina las potentes capacidades de la última generación de dispositivos de espectroscopía de fuerza atómica con toda la variedad de formación de imágenes disponibles en sus modos de medición: contacto, no contacto y fuerza pulsada. A raíz de esto, se han logrado obtener excelentes resultados de la morfología del ligante asfáltico, donde distintos investigadores han llegado a caracterizar un asfalto multi-fase definido como: la para-fase, la catana-fase, la perfase y la sal-fase. La revisión bibliográfica se realizó con el propósito de enriquecer el conocimiento acerca del comportamiento micromecánico del ligante asfáltico, lo cual servirá de base posteriormente para determinar y aplicar la técnica de indentación, la cual consiste en determinar el valor del módulo de rigidez. Por tanto el análisis del comportamiento micromecánico es una herramienta importante para las futuras investigaciones, las cuales deberían orientarse en el análisis de las propiedades del ligante asfáltico.

Marianela Espinoza Alfaro

Este trabajo tiene como objetivo dar a conocer las consideraciones básicas al momento de diseñar una capa de refuerzo con hormigón como alternativa para la rehabilitación de pavimentos existentes. Primero se evalúa  la condición del pavimento; determinando el tipo de deterioro, las reparaciones previas, así como la necesidad de preparación de la superficie; luego se identifica la posible aplicación de este tipo de solución. Las capas de refuerzo adheridas son una estrategia sustentable para preservar y extender la vida de los pavimentos que pueden usarse como rehabilitación menor, cuyo propósito principal es adicionar capacidad estructural y eliminar daños superficiales en los pavimentos existentes; esto mediante una adecuada unión entre la capa de refuerzo a colocar y el pavimento. Costa Rica actualmente cuenta con un elevado deterioro en los pavimentos que conforman la mayor parte de las carreteras de la red vial; donde muchas veces  ̶ por falta de conocimiento ̶  se eluden alternativas factibles de solución.  Por ello se realiza una investigación sobre la opción de uso de capas de refuerzo adheridas, considerando los requerimientos para ser aplicada, así como sus metodologías de diseño. A partir de la información recopilada se pretende brindar a los ingenieros viales un documento que facilite la decisión de optar por una solución ante problemas comunes encontrados en los pavimentos existentes, para lograr ampliar el conocimiento en esta área y permitir su uso en la infraestructura vial y el servicio brindado al usuario.

Eugene J. OBrien, Cathal Leahy, Bernard Enright et al.

Accurate estimates of characteristic bridge load effects are required for efficient design and assessment of bridges, and long-run traffic simulations are an effective method for estimating the effects. For multi-lane same-direction traffic, truck weights and locations on the bridge are correlated and this affects the calculated load effects. Scenario Modelling is a recently developed method, which uses weigh-in-motion data to simulate multi-lane same-direction traffic while maintaining location and weight correlations. It has been unclear however, whether the method may produce unrealistic driver behaviour when extrapolating beyond the weigh-in-motion measuring period. As weigh-in-motion databases with more than about a year of data are not available, a microsimulation traffic model, which can simulate driver behaviour, is used here to assess the accuracy of extrapolating traffic effects using Scenario Modelling. The microsimulation is used to generate an extended reference dataset against which the results of Scenario Modelling are compared. It is found that the characteristic load effects obtained using Scenario Modelling compare well with the reference dataset. As a result, for the first time researchers and practitioners can model two-lane same-direction traffic loading on bridges while being confident that the approach is generating accurate estimates of characteristic load effects as well as effectively reproducing the complex traffic correlations involved.

Rita Kleizienė, Audrius Vaitkus, Donatas Čygas

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.

Biljana Maljković, Dražen Cvitanić

Experimental investigation was conducted on a 24 km long segment of the two-lane state road to collect the driver behavior data. The research involved 20 drivers driving their own cars equipped with the GPS device. Considering the impact of path radius and speed on the side friction demand, the design consistency on horizontal curves was evaluated by determining the margins of safety. The analysis showed that the vehicle path radii were mainly smaller than curve radius, on average for 12%. Regression analysis indicated that the percentage difference between the curve radius and vehicle path radius is not affected by the speed, speed differential and geometric characteristics of the curve and surrounding elements. Two different margins of safety were analyzed. One is the difference between maximum permissible side friction (based on design speed) and side friction demand, while another is the difference between side friction supply (based on operating speed) and side friction demand. Generally, demands exceeded supply side friction factors on curves with radii smaller than 150 m, whereas “poor” conditions (in terms of Lamm’s consistency levels) were noted for curves under approximately 220 m. Both values are very close to the critical radius below which higher accident rates were observed according to several accident studies. Based on the results of the research, it is proposed to use a 12% smaller curve radius for the evaluation of margin of safety and that curves with radii smaller than 200 m should be avoided on two-lane state roads outside the built-up area.

Marija Burinskienė, Rasa Ušpalytė-Vitkūnienė, Faustina Tuminienė

Growth of towns is a result of citizen’s social and physical division. Urban planners and scientists have increased the number of links between urban transport and urban development. Public transport has been in the focus of attention as a sustainable and environmentally sensitive transport that brings environmental benefit and possibility to serve mobility needs of citizens without private cars and reduces social division. The article identifies the main factors that affect the use of public transport in town: land use planning; local government policy; extent of economic resources; implementation of modern technologies; social tendencies. Analysis of the scientific literature has revealed four main models of towns of sustainable urban forms: neo-traditional development, urban restrictions, compact town and ecological town. Vilnius has the formed urban and mono-functional structure with a high imbalance between residential and work places which conditions a high mobility of inhabitants as well as high concentration of transport flows on limited-density street networks between the western residential areas and the central part of the City where the main workplaces are located. It presents the provisions of the Vilnius City Master Plan 2015 concerning the public transport improvement. The article also assesses developments in the public transport network in 2003–2009 resulting from changes in individual routes with regard to passenger time necessary for traveling. Modelling is carried out with the help of VISUM software. Citizens of Buivydiškės and Santariškės are mostly affected by the developments, while the situation in Pavilnys, Aukštieji Paneriai and Tarandė has changed only slightly.

Atis Zariņš

Traffic safety can be defined as the quality of driving task outcome, which in its turn depends on factors within the system “Driver–Vehicle–Road”. Therefore, if analyzing concept of traffic safety from viewpoint of driving task, it must include relationships following from interactions among all the system elements. To understand these relationships and fix essential factors and elements, which must be taken into account, when making design solution or analyzing it, the system model was established. Based on this model the system functioning was analyzed. Results obtained explain importance of content and quality of information in sources from which driver obtains it for decision making. It was also established, that visual road image is the main information source for decision making in situation, where the traffic flow influence is small. Therefore, content and quality of this information, contained in road image, visible for driver, is formed and must be checked during design process.

Jerzy Paslawski

Risk management in the sphere of Construction Management concentrates, on principle, at the level of projects or organizations which coordinate them. The construction business, however, when compared to many other branches of industry, is characterized by considerable operational risk. Therefore it seems that a direct impact on risk through implementation of flexibility with the proactiveness priority taken into account at the operational (source) level is a unique chance for successful risk management in the construction process engineering. The flexibility is understood in this case as the ability of an organization executing construction processes to adjust to dynamically changing environment through preparation of alternative variants (options), easy to switch over to. The specific character of implementation of flexibility has been illustrated with an example of repairing a road construction structure, with dissimilarity of that application to typical situations being emphasized.

Evaldas Petkevičius, Alfredas Laurinavičius, Rolandas Petkevičius et al.

The article contains general characteristics of Lithuanian motor roads and possibilities of their development. 63.72% of Lithuanian motor roads of national importance (according to their length) have asphalt pavement. It is shown that modernization of national motor roads mainly includes paving of gravel roads. It is pointed out that the main indices characterizing the condition and service life of asphalt pavement and its construction are: hot mix asphalt (HMA) concrete resistance to binding tension, tensile elasticity modulus and fatigue resistance. The values of these indices highly depend on the componential composition and structure of HMA concrete as well as on the degree of its compaction. The suitability of HMA concrete for road pavement construction is well characterized by its physical mechanical indices according to Marshall: stability S, flow F, volume of air voids Va etc. These indices also are highly dependent on the composition and structure of HMA concrete. Investigations carried out in the Lithuanian motor roads and in laboratory helped to determine asphalt concrete dependencies between the componential composition of HMA concrete and values of its physical and mechanical properties according to Marshall. Conclusions and recommendations are included.