Flexible Pavement Design

The theory of viscoelasticity and its application in the modelling of flexible pavement is well documented in literature. This paper demonstrates the use of the Burger model, a constitutive rheological model to investigate the linear visco-elastic (LVE) behavior of bituminous layers. The effect of temperature on viscoelastic bituminous layers is also studied. A simple pavement section as per the guidelines of Indian Roads Congress (IRC):37-2012 has been chosen to show the creep formation behavior of bituminous layers. The pavement responses obtained from the computer program, KENLAYER, shows three stages in strain; an instantaneous elastic strain, a delayed elastic strain and viscous creep strain for various temperatures from 20° to 40°C. A comparison of the effect of temperature variation on the horizontal tensile strain at the bottom of the bituminous layer is done by considering the bituminous layer as elastic and viscoelastic, separately. Results show that the viscoelastic chara...

Computers have a direct impact on our lives nowadays. Human's interaction with the computer has modified with the passage of time as improvement in technology occurred the better the human computer interaction became. Today we are facilitated by the operating system that has reduced all the complexity of hardware and we undergo our computation in a very convenient way irrespective of the process occurring at the hardware level. Though the human computer interaction has improved but it's not done yet. If we come to the future the computer's role in our lives would be a lot more rather our life would be of the artificial intelligence. In our future the biggest resource would be component of time and wasting time for a key board entry or a mouse input would be unbearable so the need would be of the computer interaction environment that along with the complexity reduction also minimizes the time wastage in the human computer interaction. Accordingly in our future the computation would also be increased it would not be a simple operating system limited to a computer it would be computers managing our entire life activities hence fall out of domain of present computers electronic based architecture .In this research paper we propose a model that shall be meeting the future human computer interaction needs possessing linguistic human computer interference environment based on surface technology, automation and photonic computing, which would be reliable, efficient and quicker satisfying all the future artificial intelligence pre requisites.

Abstract: Highway engineers face complicated problems that are influenced by various conditions during the construction of flexible highway pavements. Identifying such problems and recommending effective solutions demand considerable engineering expertise, which is difficult to obtain at all construction sites. Thus, the development of an expert system can effectively help engineers control and analyze such problems. In addition, an expert system can effectively archive the storage and distribution of expertise among pavement ...

The purpose of the research described in this article is a comparative analysis of the predictive qualities of some models of machine learning and regression. The factors for models are the consumer characteristics of a used car: brand, transmission type, drive type, engine type, mileage, body type, year of manufacture, seller's region in Ukraine, condition of the car, information about accident, average price for analogue in Ukraine, engine volume, quantity of doors, availability of extra equipment, quantity of passenger’s seats, the first registration of a car, car was driven from abroad or not. Qualitative variables has been encoded as binary variables or by mean target encoding. The information about more than 200 thousand cars have been used for modeling. All models have been evaluated in the Python Software using Sklearn, Catboost, StatModels and Keras libraries. The following regression models and machine learning models were considered in the course of the study: linear ...

In recent years, the significant importance of solid waste management, increase in the cost of bitumen and polymer modifiers have encouraged the pavement engineers to use reusable alternative sources. Ground tire rubber (GTR) and amorphous carbon powder (ACP) are considered as two industrial waste which their using in asphalt mixture prevents their releasing in the environment. This study aims to analyze moisture sensitivity, fatigue performance, and rutting resistance of asphalt mixture influenced by using GTR (8, 12, and 16% of bitumen weight) as the modifier of bitumen properties, and ACP (25, 50, and 75% of filler weight) as filler. The results of this study shows that the ACP increases the resilient modulus and indirect tensile strength of rubberized asphalt concrete (RAC) mixtures. The results revealed that despite the negative effect of GTR on the moisture resistance of asphalt mixture, ACP improves the moisture performance. The results of fracture energy also implies that using ACP decreases the fracture energy, but using the GTR improves the fatigue resistance of asphalt mixture. Furthermore, the results of dynamic creep and wheel track tests indicates that 16GTR + 50ACP has the lowest permanent deformation and highest rutting resistance. The results of ANOVA analysis demonstrates that using GTR and ACP has a considerable effect on the performance properties of asphalt mixture. Finally, the results of this study illustrate the simultaneous use cleaner production and wasted materials decreases the environmental damages in addition to improvement of physical properties of the asphalt mixture.

The vast highways network in China is moving from the phase of construction to the phase of maintenance, and with the introduction of new technique of perpetual pavement in last decade, it is necessary to consider recycling as one of the promising solutions for rehabilitation of old asphalt concrete pavement and ultimately to convert them into perpetual pavements. The aim is to reuse the existing pavement materials for several reasons, mainly to preserve natural resources such as aggregates, and to satisfy economic requirements by reducing the cost of highway construction and rehabilitation. A detailed testing program has been carried out on recycled asphalt pavements materials (RAP) to evaluate their mechanical and structural characteristics to be used for the construction and rehabilitation of road pavements. Different types of RAP mixes have been stabilized by Portland cement to find the most suitable one from the point of view of design, construction, economy and environment. The analysis of life cycle costs has been carried out using system analysis and management of pavement program (SAMP5). The analysis of life cycle costs showed that the use of Portland cements with small percentages improves the structural characteristics of recycled asphalt materials to be used as stabilized base pavement layers for new or rehabilitated old road pavements and also for the construction and rehabilitation of perpetual pavements. A large amount of savings in construction and rehabilitation cost has been achieved by the use of stabilized RAP materials in addition to important contributions to the environment and preserving of natural resources. Introduction General Asphalt pavements are exposed to growing excessive traffic load repetitions and heavy axle loads, severe environmental conditions, and poor maintenance activities which have led to structural and functional failures. The maintenance and reconstruction costs are increasing rapidly due to the extensive volume of the deteriorated road pavements worldwide,

A research study is being undertaken to incorporate the realistic material properties of the pavement layers and the moving traffic load, in the analysis of flexible pavements, using the finite element theory. As a preliminary step taken herein in this direction, a pavement structure where field measurements have been carried out when subjected to a cyclic loading, is selected and modelled as a finite element model. The analysis is being carried out using the finite element computer package ABAQUS/STANDARD, when this pavement model is subjected to static and cyclic loading while considering the linear and non-linear material properties of the pavement layers. The results indicate that displacements under cyclic loading when non-linear materials are present, are the closest to field measured deflections. q

Abstract The performance implications of laboratory asphalt loose mixture aging at 135 °C were evaluated by comparing the performance of mixtures subjected to long-term aging at 95 °C and 135 °C to yield the same rheology. Although the rheology of the mixtures aged at 135 °C and 95 °C matched, their chemistry differed. Performance test results suggest that the chemical changes induced by aging at 135 °C can negatively impact performance. The relationship between binder chemistry and rheology was unaffected by aging temperatures at or below 95 °C. The rate of oxidation increased with an increase in temperature, and thus, the optimal loose mixture aging temperature is 95 °C.

According to IRC recommendation, the California bearing ratio (CBR) value of subgrade is used for design of flexible pavements. The design of pavement may affect by the material which is used as pavement material. Black Cotton soil is expansive soil which expand when it contacts with water and this is the major reason of failure of black cotton soil strata. The engineering properties of black cotton soil may be used by fibre, ash, lime and sludge etc. CBR value depends on the liquid limit (Wl), Plastic limit (Wp), plasticity index (Ip), maximum dry density, optimum moisture content, swelling pressure, degree of expansiveness and permeability of soil or mix specimen. These tests are performed in laboratory. This research paper deals with design of flexible pavement by using black cotton soil with different percentage of sugarcane bagasse ash. In this research, the sugarcane bagasse ash is mixed from 10% to 40% in black cotton soil. The engineering parameters are also determined by performed tests. For studying the behaviour of black cotton soil with different percentage of sugarcane bagasse ash, the Atterberg's limits (Liquid Limit, Plastic Limit, Plasticity Index), standard proctor test, California Bearing Ratio are performed.

The scope of this study is to explore and evaluate the effect of reinforcing the interface between the base and asphalt concrete layers in a flexible pavement section with bi-axial geogrids; using both large scale experimental tests and numerical modeling using three-dimensional nonlinear finite elements analysis. A laboratory characterization for each layer of the pavement section according to a laboratory programs that included soil classification, plate loading test, determination of asphalt concrete dynamic modulus for and CBR ratio for different elements in pavement section. A laboratory model of the pavement with and without the geogrid reinforcement, located at the top of the base layer was constructed. A dynamic loading scheme was applied on the experimental pavement model. Concurrently, a numerical model was developed to simulate the effect of such type of reinforcement on the pavement section in terms of the road’s performance enhancement and reduction in rutting. The nume...

Weaker soils are generally clayey and expansive in nature which are having lesser strength characteristics. Technique of improving the soil with geogrid increase the stiffness and load carrying capacity of the soil through fractional interaction between the soil and geogrid material improving black cotton soil. The load coming on the road crust is transferred to the underlying soil. If the soil supporting the road crust is weaker, the crust thickness of road increases, which leads to the more cost of construction. To achieve the economy and for proper performance of road, it is necessary to improve the soil. In the present work locally available sub-grade soil of the road is modified by addition of geotextile material in different percentage i.e.1%, 2% and 2.5% and 3% respectively. Similarly geogrid is been used for improvement in properties of soft murum has also been studied. Also geogrid is used in mix of soil and 2% cement in different proportion to study its effects. With these attempts it will be possible to find out optimum mixes which are to be used for further construction to achieve desired stability and economy in construction. For this purpose different test were performed i.e sieve analysis, liquid limit, Plastic limit, Standard proctor test to find its maximum water content and maximum dry density, specific gravity, Laboratory Unsoaked CBR and Laboratory soaked CBR test to find it resistance to penetration. For different percentage of geogrid with soil, murum and murum and cement economical cost analysis was carried out. Most economical mix with geogrid is suggested from this study.

The worksheet ELiCon (version 0.1) performs real-time viscoelastic interconversion in the time and frequency domains. ELiCon accepts as input a four-parameter analytical expression for the uniaxial creep compliance. The time-domain output consists of a list of creep compliance values for certain times, and a corresponding list of relaxation modulus values. The frequency-domain output consists of, for certain frequencies, the norm of the complex modulus and the phase angle.

This paper presents a finite element program, for the modelling of rutting of flexible pavements. In its present version, the program incorporates a permanent deformation model for unbound granular materials based on the concept of the shakedown theory developed by Zarka for metallic structures under cyclic loadings and has been used to estimate the permanent deformations of unbound granular materials (UGM) subjected to traffic loading. The calculation is performed in two steps: the first step consists in modelling the resilient behaviour of the pavement in 3D, using non-linear elastic models, to determine the stress field in the pavement. Then stress paths are derived and used to calculate the permanent deformations and the displacements, using a Drucker-Prager yield surface. An application to the prediction of the permanent deformations of experimental pavements with an unbound granular base, tested on the LCPC pavement testing facility is presented.

Selection of proper binder is one of the most important factors considered in mixture design. Three different asphalt grading systems are normally used; they are penetration grading system, viscosity grading system and performance grading (PG) systems. PG system is a method of measuring asphalt binder performance; it was originally developed during strategic highway research program in the early 1990s in

ELLVA1 (Ver 0.83) computes stresses, strains and displacements in a layered viscoelastic half-space due to a uniformly loaded circular area moving with constant speed along a straight line. Five fully bonded weightless, homogeneous, and isotropic layers are considered. Developed by Dr. Eyal Levenberg, Technion-IIT, January 2016.

 This is the top layer and the layer that comes in contact with traffic.  It provides characteristics such as friction, smoothness, drainage, etc.  It resist the pressure exerted by tires & takes up wear & tear due to traffic.  It must be water proof to protect the entire base and sub-grade from the weakening effect of water.  It provide a smooth and skid-resistant riding surface. Base Course  The base course is immediately beneath the surface course.  It distributes the loads from top layers to the underneath Sub-base and sub-grade layers.  It is constructed with hard and durable aggregates which may either stabilized or granular or both.  The thickness of base course must be great enough to reduce the load capacity on sub-grade and Sub-base courses.  Typically extend beyond the pavement edge to provide lateral support and to prevent uneven subgrade loading.

h i g h l i g h t s Marshall Test results show that 4.6% Gilsonite increase Marshall Stability. The indirect tensile test indicates the performance improvement of mixture made with Gilsonite. Test result indicates that the addition of Gilsonite to mixtures reduces moisture sensitivity. The specimens with Gilsonite have better performance to those made with pure bitumen 70-60. a b s t r a c t Iran-produced bitumen under the circumstances of severe temperature fluctuation, heavy traffic load and raining/freezing conditions show low efficiency; therefore, it is necessary to improve its properties accordingly. Existence of weakness in produced bitumen result in failure occurrence in asphalt pavements during service life of asphalt roads. Given the existence of considerable reserves of Gilsonite in Iran, its low costs compared with other additives and its remarkable properties, we can study asphalts modified by Gilsonite. At the present time, little research has been conducted on this modifier in the world and Iran (which its properties are still not quite evident for researchers). The most important failure in flexible pavements is permanent deformations which are known as rutting. Rutting is longitudinal depression in the wheel path in bituminous pavements. The rate and depth of rutting depend on the internal factors such as bitumen properties, aggregate, mixture properties and thickness of pavement layers. In this lab study, with regard to the technical and executive issues, common functional performance-based tests of bitumen were performed on specimens through adding Gilsonite with 0, 2, 4, 6, 8, 10 wt.% of made bitumen specimens. Then, the optimum percentage was calculated using the AHP. The specimens containing pure bitumen 60-70 and modified bitumen 60-70 with Gilsonite in two different aggregations (4 and 5) were made and the effects of adding Gilsonite in Marshall Stability and flow, indirect tensile strength and moisture sensitivity, as well as dynamic creep, and resilient modulus were evaluated by the UTM device. The research showed that adding Gilsonite to bitumen in hot asphalt mixtures considerably increases Marshall Stability and resilient modulus parameter in asphalt specimens. However, resilient modulus test indicated a significant reduction in flexibility property of asphalt mixtures made of modified bitumens. Moreover, increasing the flow number obtained from the dynamic creep test indicate the increase of rutting resistance.

The existing system of nebulizers are either for patients to clear spasm up to some extent and in some systems dosage limit is known. Normally most of the drug gets wasted during exhalation phase and the patients have to breathe according to the medicine flow which might cause suffocation. For persons with chronic asthma attacks may not be able to breathe effectively, for this case flow of medicine must be regulated according to one’s breathing pattern. This involves the monitoring of breathing rate. There are medicines like Albuterol, Intel solution, Ipratropium which would cause nasal bleeding, itching and nausea after the patient is nebulized. This is not an uncommon symptom in case of chronic asthma patients which requires a blood detector to stop the treatment immediately. And everything yet again needs to be reminded for care takers to provide immediate care for patient’s well being. This would require monitoring of vital parameters like temperature and heart rate. The system will now be suitable for both hospitals as well as a home care product.

The road is a land transportation infrastructure essential in facilitating the social and economic activities of the community. Wellconstructed road conditions will equip population mobility in social activities and relations. However, road damage at low and high levels will not only obstruct social and economic activities but also cause accidents. Any road pavement structure will undergo a gradual destruction process since the road was first opened for traffic. Overcoming this phenomenon requires a method to determine a road maintenance program that can be prepared using the Pavement Condition Index (PCI). The case study of this research is on Triwidadi Street, Pajangan, Bantul, Yogyakarta, and located 14 km from the zero-point of Bantul Regency. This study reviewed the four-kilometer road. The analysis results revealed that the PCI segment value was 34.75, categorized as very poor. Moreover, the highest percentage value among the 13 types of road damage was Longitudinal Crack with 22.07%.

A series of finite element (FE) simulations are carried out to evaluate the benefits of integrating a high modulus geogrid as reinforcement into the pavement layers. This paper presents a two dimensional axisymmetric finite element model that analyzes the behavior of unreinforced and geogrid reinforced bituminous pavement subjected to static and dynamic loading conditions. The critical pavement responses such as fatigue (horizontal) strain, rutting (vertical) strain and vertical surface deflection are calculated for unreinforced and geogrid reinforced flexible pavement using a pavement response model developed through a commercially available finite element program PLAXIS. Parametric studies are performed by varying the location of geogrid reinforcement i.e. base -bituminous concrete interface and the base sub-grade interface. The structural benefits of geogrid reinforcement over fatigue and rutting strain criteria have been quantified. The results obtained are qualitatively compared with the results of published literature and fairly good agreement is found in fatigue and rutting strains in the reinforced pavement. It has been found that placing geogrid reinforcement at the base-bituminous concrete interface leads to the highest reduction in fatigue (horizontal) strain. The highest decrease of vertical strain occurs when the reinforcement is placed at the interface of base and sub grade layers.

Negli ultimi quindici anni si registra una ripresa di interesse sul tema dell’abitazione collettiva con uno spostamento di attenzione dal dato quantitativo agli aspetti qualitativi e alla sperimentazione architettonica. L’Housing ruota oggi attorno ad alcuni temi prevalenti: la diversificazione dei nuclei familiari, il prevalere della trasformazione sulla realizzazione ex-novo, la moltiplicazione di usi ed esigenze che spingono sempre più alla creazione di spazi flessibili nel tempo. La riflessione su questo tema non si limita all’analisi di qualità e prestazioni del singolo edificio ma considera l’alloggio nel quadro più ampio dell'abitare contemporaneo. Il volume raccoglie e confronta trenta recenti progetti di abitazioni plurifamiliari, estraendo da essi una serie di principi tipologici e spaziali ma anche insediativi e morfologici. Nella prima parte del volume si inquadra dunque la residenza collettiva nei suoi aspetti più generali: dal significato dell’abitare, alla relazione tra housing contemporaneo e storia dell’abitazione popolare, dal rapporto dell’alloggio con lo spazio aperto, al tema del quartiere residenziale. Nella seconda parte si entra invece nel merito del come si affronta oggi un progetto di residenza collettiva, ordinando e sistematizzando invarianti e singolarità di specifici progetti, attraverso la classificazione, la scomposizione di spazi e schemi distributivi, l’integrazione ambientale tra contesto e architetture, descritte analiticamente nella terza parte.

ABSTRAK Sebagai bentuk adaptasi terhadap perubahan iklim dan beban berlebih (overloading) yang berdampak pada penurunan kinerja perkerasan jalan, maka Direktorat Jenderal Bina Marga telah mengembangkan metode perencanaan tebal perkerasan dengan mengakomodasi aspek-aspek yang berkaitan dengan umur rencana yang optimum, perbaikan tanah dasar, cuaca dan temperatur, serta beban sumbu. Untuk itu paper ini bertujuan untuk membandingkan hasil desain perkerasan antara Manual Desain Perkerasa (MDP) 2013 dengan Metode AASHTO'93 yang selama ini sering digunakan. Hasil analisis menunjukkan bahwa metode MDP 2013 merekomendasikan desain perkerasan yang lebih efesien dibanding metode AASHTO'93. Kata kunci: perkerasan lentur, MDP 2013, AASHTO'93

En este texto se involucra un análisis de la mecánica de pavimentos con un componente altamente numérico y práctico al mismo tiempo. Se maneja la teoría de la elasticidad (métodos racionales) y leyes de fatiga para los materiales que conforman las capas de los pavimentos, para el cálculo de esfuerzos y deformaciones producidos por las cargas reales de los vehículos, balanceando las admisibilidades reales de las estructuras de pavimentos. En el libro se tratan conceptos de materiales, teoría de asfaltos, métodos constructivos de pavimentos asfálticos y de concretos, diseños de estructuras -bituminosas, mixtas, inversas de concreto- y cálculo de recalzas, además de que se introduce al empleo de los elementos finitos y al análisis del fenómeno del bombeo en pavimentos rígidos.

The growing demand for public transport in cities has serious effects on urban ecosystems,
especially due to the increased atmospheric pollution and changes in land use patterns. An
ecologically sustainable urban transport system could be obtained by an appropriate mix of
alternative modes of transport resulting in the use of environmentally friendly fuels and land use
patterns. Transport, because of its pervasive nature, occupies a central position in the fabric of
modern urbanized society. In most of the countries, this has been a story of evolutionary change with
new transport development replacing the old transport system in response to perceived socio
economic needs of the people. Implementation of such modern transport system of Metro Rail
facility to MADURAI city is the ultimate aim of this project. Metro Route Maps are created as per
traffic study and evaluated in accurate manner by using GIS, Global Mapper and find out shortest
feasible route. Metro provides multiple benefits: reduction in air pollution, time saving to passengers,
reduction in accidents, reduction in traffic congestion and fuel savings. There are incremental
benefits and costs to a number of economic agents: government, private transporters, passengers,
general public and unskilled labour. The cost-benefit analysis of Madurai Metro are done in this
paper tries to measure all benefits and costs. Planning of the work done by using software
PRIMAVERA and suitable commissioning of the work be planned at 2021.The financial internal
rate of return and the economic rate of return on investments in the Metro are estimated. Those
estimates are made to be more acceptable and beneficial for financial and economic status regarding
the evaluation of metro rail project.

This project aims to evaluate the effectiveness of the quality measures employed by the Wisconsin Department of Transportation to influence the in-service performance of flexible pavements. The study involved creating a relational geo-referenced database connecting production, placement, and routine in-service performance data collected over the years for Wisconsin Projects. The database relied on geo-referencing all the data such that each individual data point is assigned a location. This approach allows for tracking the quality of the material and construction of specific segments of the roadway to the in-service performance. A subset of the projects was also included in an in-depth study using on-site distress survey and non-destructive testing using Falling Wheel Deflectometer (FWD). In general, the thirty (30) highway projects studied in this project show that transverse and longitudinal cracking are the most common distresses. Construction joint longitudinal cracking appears to be highly common in all the on-site visits. Rutting is localized but not common. Alligator cracking takes place in multiple locations. This distress appears to relate to either soft foundation or some of the quality measures.
Deviations from the quality indicators’ targets show correlations with the distresses. Mix production air voids (Va), mix voids in mineral aggregate (VMA), and placement density (%Gmm) are correlated with in-service performance. Deviation from target Va by reduction of 0.25% or more, correlates with a reduction in performance. Accomplishing VMA higher than the target is associated with lower levels of distresses. For %Gmm, about 2% increase in the compacted density show improved performance for thicker than 2” lifts. Thin lifts are more sensitive to the increase in compaction effort than thicker pavements.

A new Mechanistic-Empirical Pavement Design Guide (MEPDG), also known as the 2002 Design Guide, has been recently proposed in the United States. The development of such a procedure was conducted by the National Cooperative Highway Research Program (NCHRP) under sponsorship by the AASHTO. The Design Guide represents a challenging innovation in the way pavement design is performed: design inputs include traffic (full load spectra for single, tandem, tridem, and quad axles), material and subgrade characterization, climatic factors, performance criteria and many others. One of the most interesting aspects of the design procedure is its hierarchical approach, i.e. the consideration of different levels of inputs. Level 1 requires the engineer to obtain the most accurate design inputs (e.g., direct testing of the materials, on-site WIM, etc.). Level 2 requires testing, but the use of correlations is allowed (for example, subgrade modulus estimated through correlation with another test), and Level 3 generally uses estimated values. Thus, Level 1 has the least possible error associated with inputs, Level 2 uses regional defaults or correlations, and Level 3 is based on the default values. A trial structure is then analyzed for adequacy through the prediction of key distresses and smoothness (as a measure of ride quality): if the design does not meet desired performance criteria, the structure must be revised and the evaluation process repeated.

The increasing on air transportation passengers and the development of the remote area are factors that accelerate the needed develop of runway pavements. The research aims to find out how to design flexible pavement for runway with two methods, that is CBR (California Bearing Ratio) method and FAA (Federal Administration Aviation) method. Thick of pavement evaluated with PCN-ACN (pavement classification number) method. The designs included a range of subgrade conditions, as well as commercial aircraft and analyzed optimal budget. Case study in the research is Andi Jemma Airport, South Sulawesi. Based on analysis result from the two methods obtained the thick of pavement with CBR method is 21 inch with PCN 27,9 F/C/X/T, thick of pavement with FAA graphic method is 17,5 inch with PCN F/C/X/T and from software FAARFIELD the thick of pavement is 16 inch with PCN 16,9 F/C/X/T. The cost required for thick of pavement analyzed by CBR method is IDR 6.415.252.926, with FAA graphic method is IDR 5.897.401.963 and with the FAA software FAARFIELD is IDR 5.675.465.836. These results indicate that the models obtained for FAA (software) can be used to design the pavement, where as it optimal budget.

The inconsistencies and variations in design of pavements arising from using different methods has become a critical issue in Sudan. This paper is aimed to develop a structural design procedure for flexible pavements in order to simplify the design process by using a software program and provide a uniform structural design result. The literature of the conventional design methods commonly experienced in Sudan was intensively reviewed. In fact, these design methods were not designed to cater for the current needs and conditions of Sudan. Thus, an attempt was made to establish a simplified design procedure to accommodate the ever increasing traffic loads, available pavement materials and significant change in climate conditions in Sudan. Based on previous experiences, a design chart for a particular set of traffic loading and CBR values of subgrade soils and granular materials was developed. A software program using Visual Basic language of the Microsoft was created to facilitate the design process. To verify the validity of the developed design chart, three existing roads in Khartoum were redesigned by the new design chart and compared with their previous designs. The results proved that the new design is more realistic, reliable, and accurate design than the previous design. Therefore, adopting the developed design procedure in Sudan might help in enhancing the performance and sustainability of roads. Finally, recommendations are provided for further improvement in design of pavements in view of future developments.

This study investigates the combined efficacy of waste-tire-derived aggregate (TDA) materials and hydrated lime on the compactability, compressive strength and swelling potential of a highly expansive soil from South Australia. A total of 21 mix-designs, covering a comprehensive range of soil-TDA-lime combinations, were examined through standard Proctor compaction, unconfined compressive strength (UCS) and oedometer swell tests. The mobilized UCS exhibited a 'rise-fall' behavior, peaking at 5% TDA content and subsequently decreasing (monotonically) for higher inclusions of TDA. Increasing the TDA mean particle size (from 1.67 to 3.34 mm) also contributed positively to the UCS development. Addition of TDA to the soil/soil-lime-blends produced notable reductions in the swelling potential; the reduction was primarily governed by higher TDA contents, and, to a lesser degree, for larger TDA mean particle sizes. However, the role of TDA particle size in reducing swelling was found to be more significant than that of enhancing the UCS. As expected, lime treatment of the soil-TDA blends provided major further improvements to the UCS and swelling potential reduction; the achieved UCS improvements being positively proportional to the lime content and curing time. In view of the experimental results, soil-lime blends containing TDA to soil-lime mass ratios of up to 10% (preferably employing coarse-sandsized equivalent TDA) can be deemed as suitable choices (capable of adequately mitigating the swelling potential, while simultaneously enhancing the UCS).