Road Pavement Design Research Articles

Study concerning the conception and construction of Long-Lasting Flexible Pavements

The paper presents the current state of Long Lasting Flexible road pavement design, which is characterized by permanent development, both in terms of the calculation scheme that can reproduce as accurately as possible the actual operating behaviour and also in terms of more efficient materials usage. The research has shown that these types of flexible, well-designed and executed road pavements could have a longer lifetime than classical ones. In the same context, the energy performances and the Global Warming Potential, related to the construction and maintenance of Long-Lasting Flexible Pavements, calculated using a Life Cycle Assessment approach, are given, in order to substantiate their ecological advantages compared with a classical road pavement. This paper emphasizes the necessity to adopt appropriate constructions alternatives for road pavements, also within the initial construction phase, as well as within their maintenance and intervention stages, in order to have a sustainable build environment. In conclusion, roadwork and recent research have shown that Sustainable road pavements, known also as Long Lasting Pavements could be designed and built, resulting in significant material savings and, therefore, low maintenance costs with high performance and significantly longer service life compared to classical road pavements.

Удосконалення методу оцінки стійкості покриття нежорсткого дорожнього одягу до утворення колії

Introduction. The experience of road operations of recent years shows that one of the most common defects in asphalt pavement under the impact of traffic loads and high summer temperatures is rutting which leads to decrease of its life time and, respectively, the road pavement design as the whole. The need to improve the method of evaluation of stability of non-rigid pavement against the rutting is determined. Problem statement. Taking into account that non-rigid pavement is in complicated operational conditions (it is confirmed by intensive growth of defects, such as rutting) due to increase of traffic loads and high summer temperatures, it is needed to increase the stability of non-rigid pavement against rutting. Purpose. Purpose is to improve the method of assessing the stability of the non-rigid asphalt pavement against rutting under the impact of vertical loads of vehicles at high summer temperatures. Materials and methods. Methods of research are analytical and experimental using the provisions of the theory of elastic plasticity and thermal elasticity and experimental methods of studying the rutting formation in non-rigid asphalt pavement; methods of numerical simulation; methods of mathematical statistics. Results. On the basis of the performed analysis, the working conditions of non-rigid pavements were considered, as well as the existing theoretical and experimental methods of forecasting the rutting formation was analyzed. Analytical dependency is achieved and method of evaluation the stability of non-rigid pavement against rutting under the impact of vertical vehicle loads is improved that allow considering the complex impact of major factors, namely: thermo viscous elastic properties of asphalt, soil stabilization, asphalt temperature, vertical pressure on pavement of vehicle tires, intention of vertical pressure, time of load impact. The calculated thermoreological characteristics of asphalt concrete and reinforced soils, the adhesion strength between asphalt and the foundation during shearing were experimentally researched. Field, laboratory and bench tests of the impact of various factors on the formation of residual strains in the form of rut were carried out, as well as the regularities of impact of influence factors on the intensity of the rutting formation in non-rigid asphalt pavement. Conclusion. During work, the method of evaluation of the stability of the non-rigid pavement against the rutting was improved and the complex impact of the main factors was considered, namely: thermo viscous elastic properties of asphalt concrete, vertical pressure of vehicles on the pavement and the time of its impact on the structure; the intensity of vertical loadings. The results of research were used in the development of regulations for the design, construction, reconstruction, repair and operation of asphalt pavements on highways of Ukraine.

Analisis Lalu Lintas pada Ruas Jalan Lingkar Sicincin-Lubuk Alung Kab.Padang Pariaman untuk Disain Perkerasan

Traffic is an important part of road pavement design in addition to subgrade strength. This is because traffic is a burden for the road and is very decisive in the thick planning of each layer of pavement. Thus the calculation of the traffic load should have been carried out before carrying out the design of the pavement. The Sicincin - Lubuk Alung ring road section located in Kab.Padang Pariaman is one of the road sections designed with pavement design. Therefore, a traffic survey was carried out on the road section.
 Traffic surveys are carried out for three days, two days on weekdays and one day on holidays. Every day the survey time is divided into three times, morning, afternoon and evening at rush hour. The survey in the morning takes place at 07:15 - 08:15 and 08:15 - 09:15 while in the afternoon it takes place at 13:00 - 14:00 and 14:00 - 15:00. Furthermore, for the afternoon survey, it will be held at 16:00 - 17:00 and 17:00 - 18:00. After processing the data, in each survey period the LHR value is obtained for both directions. The LHR value used for pavement design is the largest LHR value of all LHR values obtained.

Road pavement design using the finite element method

The purpose of the work is to calculate the stress-strain state of the III-type road, as well as to determine the load factor for road pavement and roadbed. A model of non-rigid road pavement consisting of 4 layers is considered: dense-graded asphalt concrete, open-graded asphalt concrete, gravel roadbed, ground roadbed (silt sandy loam). A numerical code is developed for calculating the principal physical and mechanical parameters of road pavement. C++ is used as a programming language. A method of evaluating the shear resistance of roadbed is proposed. To calculate the load factor of roadbed, the Drucker-Prager strength criterion is used without the term responsible for the intensity of tangential stress. A T-90 tank fitted with special rubber track pads is considered to be a static load. The computations reveal the maximum vertical deflection, equal to 0.004 m, in the contact area of the tracks. In the same area, the load factor of road pavement is 9 ÷ 10, which indicates a high bearing capacity of dense-graded asphalt concrete. The analysis of shear resistance shows the presence of irreversible deformations in gravel roadbed in the contact area of the tracks, while the load factor of silt sandy loam is 3 ÷ 10.

Use of slag (with cement) for improving the performance of expansive soil of road pavement subgrade

The study presented in this paper evaluates the suitability of using slag (with cement) as a stabilizer, for improving the performance of expansive subgrade soil in road pavement. Several laboratory tests were conducted to determine the geotechnical engineering characteristics of the expansive soil and associated mechanical engineering performance. The tests conducted include the particle size distribution, standard Proctor compaction, Atterberg’s limits, free swelling, permeability, California bearing ratio (CBR), unconfined compressive strength (UCS), and repeated load triaxial (RLT). In this study, the use of slag (with cement) as a stabilizer followed three proportion schemes, and the selection of a specific stabilizer proportion was determined based on UCS value that satisfies the required standard as a subgrade for road pavement. The results recommended a stabilizer proportion for the soil studied to be 13.5% slag + 1.5% cement at 28 days curing time. This mixture resulted in a remarkable increase in the UCS value of eight times higher than the UCS value of the non-stabilized soil. The CBR value of the mixture was four times higher than the minimum required value for design of road pavement. The study presented herein confirmed that the exploitation of the by-product material of slag can indeed be useful, both in terms of improving the performance of the subgrade soil for road pavement and sparing the environment a spread of significant potential pollutant.

Основы проектирования нежестких дорожных одежд международных автомобильных дорог для условий жаркого климата с учетом возрастающих нагрузок и движения

Основы проектирования нежестких дорожных одежд международных автомобильных дорог для условий жаркого климата с учетом возрастающих нагрузок и движения

DESAIN TEBAL PERKERASAN TERHADAP VOLUME LALU LINTAS PADA KONDISI TANAH RAWA JALAN LABUHA–TOMORI BACAN KABUPATEN HALMAHERA SELATAN

This research was carried out on Jalan Oesman Shah on Labuha-Tomori Road. In determiningflexible pavement thickness, based on the results of analysis and calculation of PavementThickness Design Against Traffic Volume on Swamp Conditions on the Labuha-Tomori RoadSection using the Road Pavement Design Manual Number 02 / M / BM / 2013. Based on theexisting plan, this Labuha-Tomori road section in South Halmahera Regency, North MalukuProvince is an arterial road with 2-lane 2-way road type using the median (2/2 UD), plan width of10 meters, width of existing traffic lane 4, 5 meters, median width of 1 meter, and plannedshoulder width 2.40 m. Based on the results of the analysis of growth rates obtained traffic growthrates of 33.066% over the life of the plan, determining the distribution factor of the lane and thecapacity of the lane of lane 1 and the vehicle in the design lane taken 100%. The equivalent loadfactor can be determined using the value of VDF (Vehicle Damage Factor) according to thesurvey results in the field. The traffic volume plan to determine the CESA4 value = 18,835,021.85= 18.84 million is used for the selection of pavement types while the CESA5 value =33,903,039.33 = 33.90 million is used to determine the type of flexible pavement based on thedesign chart provided in The Road Pavement Design Manual Number 02 / M / BM / 2013, ishighly emphasized in terms of the improvement of subgrade, by looking at the condition of theCBR of the subgrade and CESA5 which will be received by pavement. So if the pavement CBR is5.20% and CESA5 is 33.90 Million, the flexible pavement design is of 2 kinds in the design ofpavement thickness: AC - WC = 4 cm, AC - BC = 15.5 cm, CTB = 15 cm, LPA Class A = 15 cm,Choice of 10 cm and AC - WC = 4 cm, AC - BC = 6 cm, AC BASE = 18 cm, LPA = 30 cm, Choiceof Stock = 10 cm, and Subgrade = 5.20%

Pavement layer thickness variability evaluation and effect on performance life

ABSTRACTThis paper aims to assess the sensitivity of road pavement design and predicted life to pavement layer thickness, accounting for the variations which commonly occur between the pavement design thickness specified and that actually constructed. The approach adopted in this research is to characterise the as-built pavement layer thickness variation, obtained from Ground Penetrating Radar (GPR) surveys, for lane 1 of a UK motorway site with flexible pavement construction. Firstly, an analysis is conducted for the selected UK motorway to explore the relationship between the specified construction tolerances and the actual thickness variability. Secondly, the paper proves how variability of layer thickness – while keeping all the other design parameters unchanged – affects the design life probability distribution. The results from this study show that asphalt layer thickness variation significantly affects the pavement performance, even when such variations are within the tolerances allowed by UK construction specifications. On the other hand, layer thickness variations in granular sub-base, within allowed limits, do not significantly affect the pavement performance.

On the parametric and external resonances of rectangular plates on an elastic foundation traversed by sequential masses

Elastodynamic behavior analysis of structures under moving loads is of great interest in most engineering fields. In this study, dynamic instability due to parametric and external resonances of simply supported thin rectangular plates on an elastic foundation under successive moving masses is investigated as a linear time-periodic problem. Effects of all components of moving mass inertia are considered in the analysis. The governing partial differential equation of motion is transformed to a set of ordinary differential equations using the Galerkin method. A comprehensive study of resonance conditions is carried out for two cases: (1) the masses move on a rectilinear path parallel to the longitudinal edges of the plate, and (2) a sequence of moving masses along the diagonal of the plate. Homotopy perturbation method (HPM) is employed as a semi-analytical method to obtain stable and unstable zones in a parameters space in additions to external resonance curves. In order to validate the HPM results, Floquet theory is applied to the state-space equations. A good agreement between two methods is observed. The results of this study are useful for the design of road pavements resting on foundation soil, slab-type bridges, airport pavements, and decks of ships on which aircrafts land.

Optimization of low volume road pavement design and construction

Low volume roads in the Czech Republic are roads with lower traffic volume that primarily include forest and field roads, and they are an integral part of the Czech transport network. When building road pavements, we can use processes for surveying, designing, building and inspecting road constructions included in national and international, particularly European, standards. In addition, the roads are evaluated in terms of their environmental impacts, in order to maintain the quality of the environment. However, during the construction of road pavements decisions based on financial, time and other reasons are made. The decisions have impacts on the operation of roads and lead to other measures and additional costs of repairs and reconstructions. The article summarizes the authors’ research results from constructions of low volume road pavements and contains evaluations of laboratory and in situ material tests (soils, layers) of installed road pavements as well as evaluations of modelled laboratory and long-term monitored in situ structures.

Improvement the california bearing ratio of expansive subgrade using SiCC column

In Indonesia, many main roads have been constructed on problematic soil. The chemical improvement is widely used to shallow soil modification and stabilization. This paper introduces the use of a SiCC column to strengthen the load-bearing capacity of the expansive soil. In the road pavement design, California Bearing Ratio (CBR) is a most useful parameter to define the pavement layers. Hence, this paper is aimed to investigate the effect of SiCC column on the CBR of compacted expansive soil. Two groups of specimens were prepared for CBR test under soaked condition. A set of specimens are prepared on the wet side (Specimen A), and a set of specimens are compacted on the dry side of optimum moisture content (Specimen B). The objective of this research is to determine the effect of moisture content and dry density on the CBR value. The experiment results show that the SiCC column significantly increases the CBR of expansive soil on both dry and wet side of optimum moisture content. The specimen compacted on the dry side exhibit a higher CBR than the specimen compacted on the wet side of optimum moisture content.

The modelling prediction of haul road surface deflection

Abstract Haul road pavement design is often completed through application of axisymmetric linear-elastic modelling. This may be implemented either through the derivation of cover curves employing the California Bearing Ratio, or within linear-elastic modelling completed by commercially available software. In recent years, a significant amount of research has been conducted on the application of the Finite Element Method for the analysis of pavements. A study to determine the accuracy of predicted haul road pavement response made by various linear-elastic and Finite Element Methods was undertaken. The deflected pavement surface profile was measured for three haul road pavement sections utilising terrestrial laser scanning, which also allowed measurement of the tyre/pavement contact geometry. Laboratory testing was completed to define the stiffness of each material through triaxial testing. Results of the field and laboratory testing allowed modelling via each method. Only minor variations were observed between the various linear-elastic modelling approaches that were investigated. In general, the Finite Element Method was found to produce the most accurate predictions. These findings provide the impetus for further investigation and the use of Finite Element Method for haul road pavement modelling.

Climatic Characteristics of Slovakia in the Years 1971 to 2011 from the Aspect of Pavement Design

Contribution follows the previous work of authors in the field of implementation of objectified results of climate change in the design of roads, especially their pavement [1] to [3]. Climate conditions are besides traffic load, one of the permanent external factors adversely affecting the physical and mechanical properties of the construction layers. For designing concrete pavements is used in SR conditions average annual air temperature Tm and frost index for design of asphalt and concrete pavements. As part of the research activities carried out at the workplace, the authors statistically evaluated average daily temperatures of SR meteorological stations covering most of the SR territory with altitude from 115 to 695 m above sea level in the years 1971 to 2011. Act No. 135/1961 Coll. (Road Act) states that the design of road pavements is performed according to valid Slovak technical standards, technical regulations and objectively identified results of research and development for road infrastructure. On the basis of the presented correlations, it can be stated that the presented research results can be used immediately for SR conditions in the design of road pavements.

Book review

Highways: the Location, Design, Construction and Maintenance of Road Pavements, Fifth edition

The effect of wetting and drying on the performance of stabilized subgrade soils

Abstract Stabilization methods are often utilized to improve the performance of road pavement subgrades which are weak or susceptible to small changes in moisture content. However, although a variety of performance models for natural materials have been developed and incorporated within road pavement design methodologies little research attention has been given to the characterization of similar performance models for stabilized subgrade soils. To address this, the research reported herein describes and discusses the results of a laboratory testing programme, incorporating cycles of wetting and drying, for a number of stabilized subgrade soils to determine the resilient behaviour and permanent deformation characteristics of the soils. The results from the experiments were used to characterise six models of subgrade soil permanent deformation performance identified from the literature and from these to develop a new improved model of performance which incorporates resilient behaviour. A comparison of the existing models of permanent deformation showed that those which consider stress state in addition to the number of load repetitions are better able to predict permanent deformation than those which consider the number of load cycles only. Samples subject to wetting and drying exhibited significantly greater permanent deformation and had lower values of resilient modulus than those which were not subject to wetting and drying. The usefulness of the results for analytical road pavement design are demonstrated by using a back-analysis procedure to determine appropriate resilient modulus values to characterise an analytical model of a road pavement together with the performance models to predict road pavement subgrade performance under cumulative applications of traffic load. Accordingly, the results show the importance of adequately replicating material behaviour in field conditions. In particular, the design process must utilize resilient modules values and deformation models which are determined in conditions which take into account in-situ stresses and cycles of wetting and drying.

Analysis of the sensitivity of the impact resonance frequency test as a tool to determine the elastic properties of bituminous materials

The modulus value of bituminous materials is a key factor in the design of road pavements and the estimation of their life service. This parameter can be measured in laboratory but, unfortunately, this requires the deterioration of the pavement so as the consumption of time and resources. Therefore, this study analyses the feasibility of using impact resonance frequency tests as an alternative to traditional methods for determining the dynamic modulus of bituminous mixtures. The sensitivity of this technique has been studied by analyzing its repeatability and reproducibility, studying the variations in the values measured by modifying the dimensions of the specimens, test temperatures and types of mixture tested. In addition, this non-destructive technique has been compared with other traditional tests used to determine the elastic properties of bituminous materials. The results show that this test could be an interesting tool to characterize the properties and damage state of asphalt layers.

走行速度を抑制する路面デザイン シェアード・スペースのためのデザイン提案

走行速度を抑制する路面デザイン シェアード・スペースのためのデザイン提案

Aplicación del pesaje de vehículos en movimiento al dimensionamiento de firmes. Influencia de la precisión de los pesajes

El pesaje de vehículos en movimiento permite conocer los pesos de los vehículos y sus ejes cuando circulan a su velocidad normal de recorrido. En este artículo se describe su aplicación al dimensionamiento de firmes viarios y se estudia la influencia de la precisión de los datos obtenidos mediante el pesaje dinámico en el cálculo de la vida útil de los firmes. Para ello se describen, primeramente, los principales factores que afectan a la precisión del pesaje en movimiento, en especial, la interacción entre el vehículo y el pavimento. Luego, se presenta un ensayo realizado para comprobar el efecto de la precisión de los pesajes dinámicos en la estimación de la vida útil de los firmes. Los resultados obtenidos indican que los errores de las mediciones de pesos se incrementan notablemente al determinar la vida útil del firme.

Numerical modelling of flexible pavement incorporating cross-anisotropic material properties. Part I: Surface circular loading

Accurate numerical modelling of the behaviour of road pavement layers is an important requirement for the design and evaluation of road pavements. This modelling includes the prediction of pavement performance under the action of traffic loading and environmental factors. Depending on the complexity of the models, properties of pavement layers that may be considered are wide-ranging - from linear or nonlinear elastic to cross-anisotropic through to linear visco-elasto-plastic. Some properties, such as cross-anisotropic, are not only related to placement and compaction of the pavement layers, but are also inherent to the materials used. Other properties, such as linear visco-elasto-plastic, are specific to asphalt concrete and depend on the speed and magnitude of traffic loading, as well as the environment (temperature) in which the road is located. This paper presents basic theoretical derivation of numerical modelling of a flexible pavement considering cross-anisotropic material properties (with isotropic properties as a special case). The solutions derived in this paper are based on Hankel transformation of Navier's equations. The accuracy and validity of the solutions are verified through comparisons with a proprietary finite element method (FEM) package. For this purpose, a pavement structure composed of five main layers constituted by isotropic and cross-anisotropic (also known as transversely isotropic) material properties is analysed. In order to vary some of the layer properties with depth, the main layers were sub-layered, resulting in a 17-layer pavement system.

Influence of drainage on flexible road pavement design

Road pavement serviceability is primarily governed by the type of vehicles anticipated to use the facility. Along with the size of traffic loads, climatic conditions affect the behavior of the materials in a pavement structure. The relative strength loss in a layer due to its drainage characteristics and the total time it is exposed to near-saturation moisture conditions is represented by drainage coefficients. There is a need for computerized methodologies for thickness design of flexible asphalt pavements (granular base course) for a wide variety of pavement uses providing users the capability to conduct structural analysis of special pavement structures. An algorithm for a computer-based procedure towards the calculation of the layer thickness of flexible pavements has been developed. The design equation used is that described by the American Association of State Highway and Transportation Officials. The present work deals with the effect of drainage on the total thickness of the structure as it directly influences the cost of large infrastructure projects like roads. The output of different cases solved is presented in table and schematic form. Changes in technology related to pavement design and construction practices will necessitate revisions to currently used computing techniques. Improvements in computing times which will affect the cost of computerized methods available to engineers are to be suggested in the near future. Empirically supported pavement designs used nowadays in Greece require modifications based on regional experience and on a better assessment of the drainage conditions prevailing in each area crossed by a roadway project. Since design considerations constantly change, it is obligatory to shift towards more sophisticated design methods.