No abstract

In Iraq rutting is considered as a real distress in flexible pavements as a result of high summer temperature, and increased axle loads. This distress majorly affects asphalt pavement performance, lessens the pavement useful service life and makes serious hazards for highway users. Performance of HMA mixtures against rutting using Mechanistic- Empirical approach is predicted by considering Wheel-Tracking test and employing the Superpave mix design requirements. Roller Wheel Compactor has been locally manufactured to prepare slab specimens. In view of study laboratory outcomes that are judged to be simulative of field loading conditions, models are developed for predicting permanent strain of compacted samples of local asphalt concrete mixtures after considering the stress level, properties of local material and environmental impacts variables. All in all, laboratory results were produced utilizing statistical analysis with the aid of SPSS software. Permanent strain models for asphalt concrete mixtures were developed as a function of: number of passes, temperature, asphalt content, viscosity, air voids and additive content. Mechanistic Empirical design approach through the MnPAVE software was applied to characterize rutting in HMA and to predict allowable number of loading repetitions of mixtures as a function of expected traffic loads, material properties, and environmental temperature.

Baghdad suffers a deficiency in the application of urban transportation planning process, especially in selecting the suitable transport policies to solve transportation problems. One of the important inputs to the transportation planning process is the Origin – Destination Matrix. The O-D matrix is the travel demand between the pair of origin and destination zones and is one of the necessary goals of transportation studies. Estimation of an O-D matrix using the conventional process requires the collection of a huge amount of data. In Baghdad city, there has been no O-D matrix formulated. Accordingly, a prior O-D matrix is estimated in this study. The present research methodology is based on the estimated O-D matrix for Baghdad city in 1987 (prior matrix) and then updated to 2014 using the collected traffic count data as the basis for travel forecasting. The results of this study provide a guide to the local transportation agencies to select the right transport policies, maximize their revenue and better allocate their resources.

ABSTRACT:The present paper articulates the applicability of genetic algorithms (GAs) as an optimization tool capable of supporting decision-makers (DMs) to make the right decisions throughout the selection of an optimal pavement maintenance strategy and to predict future pavement condition. GAs efficiently take advantage of historical information to locate search points with improved performance. In this regard, pavement condition index (PCI) for the in-service pavement of the selected case study (Expressway No.1 (R4/A) in Iraq) is estimated based on ASTM D6433-11 and using MicroPAVER 6.5.2 software. Moreover, the related field measurements of the in-service pavement distresses are carried out and classified. To predict the optimal maintenance strategy for the pavement segments within the selected pavement portion case study, a GA optimization technique is implemented as an application of stochastic approach using EVOLVER 6.3.1 software to evaluate the pavement performance based on PCI. For the required validation process of the predicted PCI results obtained by the GA technique, predicted PCI results obtained by experts' opinions based on the design questionnaire were estimated and applied. The statistical validation analyses showed that the predicted PCI values obtained via EVOLVER 6 Genetic Algorithm software seem to be close to those obtained via the analyses of the experts' questionnaires. Based on the research outcomes, it is concluded that one can recognize using the presented procedure throughout the implementation of stochastic approach in the form of GA to predict the optimal pavement maintenance strategy for in-service pavement.

The quick imperative for transportation development has driven thruway specialists to find safe approaches to construct the foundation of roadway on delicate subgrade layers. Nonetheless, Delicate immersed fine-grained subgrade soils are remarkable by extraordinary volume change and little shear quality. Numerous issues identified with building roadway dikes over delicate subgrade layer i.e.; dikes flimsiness, high settlements and tedious required for union of the establishment soil. The impact of utilizing Heaped dike to upgrade the execution of asphalt frameworks including increment the roadway benefit life. The investigational work included paired models: crude materials model and heaps show were considered. A research center model tests are completed to created the black-top asphalt layers and configuration cycling load framework likewise to the standard single pivot wheel stack, that were organized amid a plan and amassing of metal Box show. Three-dimensional (3-D) limited component models has been altered in this work for adaptable asphalt setup utilizing ABAQUS programming ver.6.14.4 to break down and reenact the reaction of the asphalt layers of all models with the cycles connected load and soil relocation. The aftereffects of this work demonstrate that the lasting dislodging at the surface of black-top solid (air conditioning) layer utilizing the heap strategy display as contrasted and the crude material model shows diminishes by (14.62%). The consequences of ABAQUS program have a decent concurrence with the trial results.