پژوهشنامه حمل و نقل
سال هفدهم شماره 3 (پیاپی 64، پاییز 1399)

The purpose of this paper is to investigate the effect of coal waste ash and rice husk ash on mechanical properties of the stone matrix asphalt mixtures. In this study, of coal waste ash and rice husk ashes was used as a substitute for limestone powder in percentages (0 %, 25 %, 75 %, 75 % and 100 %)in the stone matrix asphalt mixtures. also to prevent drain down of this mixture, the cellulose fibers and SBS polymer fibers were used. in order to investigate the performance characteristics of mixtures the Marshall stability test,  Resilient modulus, indirect tensile strength, moisture  sensitivity, dynamic creep, and wheel tracking tests were performed. the results showed that the replacement of rice husk ash with limestone powder has improved the performance characteristics of the mixture. While the use of coal waste ash is only enhanced the moisture sensitivity of mixtures and it has a negative effect on the performance properties of mixtures.

The major national investment in the transportation sector is the creation and construction of pavements. Currently in Iran, most of the pavements are asphalt mixture. It has been damaged by the passage of time, traffic loads, and atmospheric changes. One of the most important types of flexible pavements is the change of permanent forms known as rutting. In recent years, the use of metal melting slag, one of the waste of the metal melting plants, has been considered as an alternative to parts or all rock materials in different layers of metal. in this study, we investigated the use of different percentages of steel slag as a percentage of coarse rock material in gradation of mixture (0 - 25 - 75 - 75 % of slag in alternative rock material)… using the method of mixing marshall, optimum bitumen and other Marshall parameters. In order to investigate the properties of the pure bitumen, penetration point, ductility, viscosity, and degree of fire were performed. Also, the tests of marshall and flow, indirect tensile, moisture susceptibility, resilient modulus, dynamic creep and wheel placement were performed to investigate the effect of the use of فولاد slag on the functional properties of asphalt mixture. The results of this study showed that the compressive strength, indirect tensile strength and tensile strength ratio (saturation to dry of mixtures containing electric arc furnace (EAF) steel slag were higher than control mixture.

Road safety is recognized as one of the most important factors in transportation system of the world as well as in reducing road accidents. Currently, heavy expenses are spent for reducing road accidents and casualties, however, authorizes haven't so far achieved satisfactory and desirable results. It appears that adoption of global solutions might be effective in securing roads safety and making necessary planning and management in this regard. In the present study, researcher with the use of AHP Fuzzy method has tried to identify and determine the importance level of the effective factors on the safety of northern roads in Iran. For this purpose, a research population consisted of 125 traffic and transport mangers, practitioners and experts have responded to a 78-item questionnaire and finally, 23 factors were identified as the effective factors on safety of the northern roads of Iran. Research results indicated that with the adoption of AHP FUZZY method, the indicators of advertising in national media, reduced average age of vehicles and appropriate designing of road geometry respectively have the highest weight and importance with 0.126, 0.082 and 0.065 weights.

Energy is one of the most important issues of the world today. Given the limited energy resources and the increase in the prices of energy carriers in Iran, identification of methods and solutions for supplying resources and energy consumption in the energy and energy industries such as transportation is very necessary. In this regard, due to the rich natural resources of the country and the government's investment in this sector, the importance and role of compressed natural gas (CNG) as one of the best gasoline alternatives in cars in the past years has been identified. On the other hand, due to the role of various factors in economics, politics and society in the performance of this industry, policy and planning are associated with particular complexities. Hence, in this paper, a systematic approach is proposed to provide appropriate solutions for the development of optimal use of compressed natural gas (CNG) instead of petrol as a fuel for the road transport sector based on the important impacts of this industry and their effectiveness on the basis of the dynamic system Designed and decomposed. An approach that involves and interacts with all the factors involved, as well as adopting a glimpse into the compressed natural gas (CNG) industries in the transportation sector, provides appropriate solutions for the development of an appropriate economic system. Accurate and timely information, creates a long-term program for the fuel basket, Suitable fuel prices, the proportions of the growth of Duncan cars with compressed natural gas (CNG) supply sites, are known as effective development variables in use of compressed natural gas (CNG) instead of gas is known in Iran's road transport system. Finally, make the necessary and effective suggestions based on the systematic analysis to create a growing trend to government officials and policy makers.

The need for a suitable Roller Compacted Concrete Pavement (RCCP) has effective role in the use of this concrete in the pavement. In order to achieve the desired Roller Compacted Concrete, an optimal mixing plan is required to have optimal mixing parameters such as kind of stone materials, type of aggregate, type and amount cement consumption; and other properties of its ingredients can play a significant role. In this paper, by changing the RCC’s gradation in 8 different types, inside and outside the specified range of regulations, and 5 different percentages of cements, compressive strength of the cylindrical samples were tested and calculated to determine the optimal amount of cement and optimum granulation. The results of this experiment showed that the mixing plan with 34% fine grained and 66% coarse presented the best and optimal compressive strength. The concrete compressive strength of Rolled Compacted Concrete was increased by increasing the cement up to limited amount .

Tehran citizens suffer from hardly found public parking spots on their daily intra-city trips. Official statistics published by the Tehran Municipality affirms the high gap between the public parking supply and the demand all over the city. This gap is a result of decades of shortfalls in developing public parking in the city. The contributing factors which have prevented the authorities from solving the issue during past years have not been investigated yet. To address this problem, this research investigated the Tehran’s parking development issue from different aspects. An assessment was carried out according to the thorough literature review and field survey of four major stakeholders, including car owners, public parking investors, public parking operators, and the city authorities. The questionnaire-based survey conducted among car drivers in the city showed the majority of them spend more than 10 minutes finding free parking spots. The wasted time creates high stress among car drivers. The majority of car drivers were interested in the parking areas close to their destinations. Consequently, on-street parking spots were more favorable than the off-site parking areas. In the conducted interviews low profitability of the parking investment, not taking the issue seriously by the authorities, high costs of parking construction permits, poorly regulated car park rates and high parking operation costs were identified as the main influential factors to the parking problem. Giving a high priority to this issue by the city authorities, proactivity regulating the car park rates in different parts of the city, creating new parking investment incentives such as tax exemptions and granting commercial permits, and implementing new regulations encouraging parking owners in using off-street parking were among the recommended solutions. The achieved results of the research can be used as inputs for future decisions in the Tehran Municipality.

This study was intended to evaluate the susceptibility of asphalt binders and mixtures to rutting. The binders have the same high PG grade (PG 76-xx) and a dense-graded gradation curve was used to produce the mixtures. Three types of polymers – Elvaloy, SBS and SBR – and polyphosphoric acid (PPA) were selected. The tests included softening point, oscillatory shear (parameter G⁄/sind), multiple stress creep and recovery (Jnr) and flow number (FN). The rankings of binder and mixture parameters (Jnr, G⁄/sind, softening point and FN) are the same only for Jnr and FN, and the applicability of G⁄/sind to modified materials is questionable.

The transportation industry of any country represents the economic situation and the extent of its industrial development, so it can be considered as one of the important factors in the economic, cultural and social development, etc. of each region. Therefore, the growth of economic activities in Iran and the need for faster transportation of people and goods enables the country to serve as the main transport hub for export, import and transit. Reviewing the role of this type of Transportation is important in economic growth and can be effective in identifying opportunities and challenges, and ultimately providing a better view for policymakers and operators in this field. Accordingly, the purpose of this study is to investigate the role of air transportation (number of passengers and the volume of freight transported) on economic value added in the provinces of the country (31 provinces) between 2005 and 2017. The results of this study, using the dynamic panel econometric approach (Generalized Method of Moments or GMM), show the positive and significant effects of variables on the number of air transport passengers and education, as well as the negative and significant effects of unemployment and the volume of freight transported by air transportation on the economic value added of the provinces of Iran. According to the results, it can be argued that air transportation of passenger in the country's situation during the period of this study can be the factor for growing economic value-added, while, the freight transportation in terms of the costs has not economic efficiency. Furthermore, the results illustrate that establishing international airports in the province has a positive effect on economic value-added and also the value-added of the previous period has positive and significant effects on current economic value-added which represent dynamic of growth.

Because of the destructive effects of greenhouse gas emitted by fossil fuels, moving to alternative fuels is an unavoidable. Alternative fuels play a very important role in the transition to a sustainable and clean the transportation sector. The adoption of alternative fuel vehicle fleets is not easy and, particularly at the beginning of the transition period, the lack of infrastructure for producing, distributing and delivering the alternative fuel is one of the most important obstacles. Therefore, the location of alternative fuel stations is an important topic in accelerating the entry of this fuel into the transportation system. Due to the lack of refueling stations, the assumption that all vehicles on intercity trips can travel all paths with only one alternative fuel is unrealistic. One of the practical ways is utilize of bi-fuel vehicles, to use gasoline in an emergency for avoid to stopping the vehicle on the journey by run out of alternative fuel. In this paper, we present a new model to location of alternative fuel station for bi-fuel vehicles. The model's goal is to minimize total emissions from vehicles. Also, we propose an efficient solution algorithm based on Benders decomposition to solve large network. The results show that the use of bi-fuel vehicles can lead to a significant reduce in greenhouse emissions. Moreover, implementation of proposed algorithm on randomly generated examples illustrate that the algorithm is useful in reducing the solving time and obtaining acceptable solution.

Studies show that of all petroleum products, a significant share (about 30%) is allocated to gasoline consumption; therefore, proper management of vehicle fuel consumption can have positive effects on economic and environmental aspects. In the present study, in order to investigate the effect of the pavement roughness and the longitudinal slope on fuel consumption, the pavement roughness and the longitudinal slope of three freeways including Tehran-Saveh, Tehran-Karaj and Tehran-Qom freeways, were measured in one hundred sections using a road surface profiler. Furthermore, by installing a Bluetooth diagram on the test vehicle, the amount of the fuel consumption was recorded for each section. Statistical analysis of the data showed that the pavement roughness and the longitudinal slope increase the vehicle fuel consumption significantly. In this study, an equation was proposed to predict the fuel consumption of the vehicles on freeways. According to the proposed equation, Fuel consumption increases 2 percent when International roughness index increases 1m/km.

In this research, the effect of pH of the environment on the mechanical and volumetric properties of cement stabilized clay soils has been investigated through various tests in a laboratory scale. In this research, a problem-sensitive clay with chemical stabilization by cement in three short, medium and long term (3, 7 and 40 days) curing days under different pH conditions vary from acidic to alkaline with the pH of 4, 7 and 10 was tested in order to evaluate its mechanical and volumetric properties. Specifications for mechanical evaluation in this study included a test of density, single-axis bearing and California Bearing (CBR) test, which were used in different conditions in terms of the degree of acidity and curing days on specimens. The California Bearing Test (CBR) was also used to evaluate the volumetric properties. The results of this study show that soil improvement by cement increases mechanical strength and decreases the rate of soil swelling over time and curing days. However, the degree of acidity of the environment affects the chemical reactions of soil and cement, especially cement hydration, and causes changes in soil resistance and on the volume changes due to inflation. This effect depends on the pH and curing days.

The rheological properties directly affect the mechanical properties of hot mixtures at different temperatures. Recent research has shown that the use of nano-materials results in improving functional properties. In this study, some tests have been done to compare the performance properties of the modified asphalt mixtures with carbon nanotubes and no additives. Mechanical properties of asphalt were evaluated including resilient modulus, creep behavior and fatigue performance. The results of this study show a significant improvement in the mechanical properties of asphalt mixture containing the carbon nanotube, against the phenomenon of fatigue and constant deformation compared to the conventional asphalt mixture.

Dual overflow and job contradictions are one of the most important issues for employees in organizations all over the world and in Iran. This conflict is different in developing countries, such as Iran, due to their centralization and structural complexities, depending on their organization and their functional nature. The purpose of this research is Design of Work-Family and Family-Work Model. The method of the present research, in terms of its outcome, is a component of developmental research, as a target for exploratory research, and as a method of implementing quality work. In this research, interviews were conducted with 12 human resource specialists who were selected through targeted sampling. Interviews were conducted in-person interviews and in-depth interviews. To assess the reliability of the data and interpretations, the criteria for interpretive research were based on two criteria of acceptance and plurality. Based on GRANDED's method, the theory of analysis was performed in three stages of open, axial, and selective coding and the design of the paradigm of research was designed. Based on the designed model, the causal conditions include three main components of "work-family overflow", "job conflict" and "family-work overflow". The underlying conditions include three types of psychological well-being, attitudes and ambiguity in the role, and in the intervening conditions the three components of policy making, interest-seeking and the role of rules and regulations were identified. The pivotal phenomenon of research is based on the key words of interviews, overflow and job contradictions. Based on the identification of the criteria of the three causal, background and interventional criteria, strategies and outcomes were presented. Strategies included three organizational, psychological, and transactional strategies, and the outcomes including structural, axis-driven, and development-oriented axes were identified.

In the past years and with the start of Autumn and Winter seasons in Tehran, when vehicle emission rates reached their maximum amount in Tehran and According to the approved plan of the emergency committee for air pollution in Tehran, traffic congestion zone was extended to the Odd-Even plan area and many of the citizens changed their way of access to the area and other citizens paid the tolls to travel inside the zone with their private vehicles. In this research, first, the interviewees were asked to determine how they have traveled to the Odd-Even plan area. In the following, the proposed hypothesis was based on this assumption that if the traffic congestion zone due to the air pollution problem, is extended to Odd-Even plan area, According to the different scenarios, which travelling means they choose. After reviewing the results obtained from the questionnaire and using the Aimsun simulation software, the amount of emissions produced by the movement of vehicles when implementing the Odd-Even plan area within their range and the above scenarios have been investigated and evaluated. the results of this study show that the most ideal mode for reduction of pollutant values in the Odd-Even plan area, was with an increase of 40-75 % of the money allocated for the traffic congestion zone in the year of 2016 and with extending of that in the Odd-Even plan area, The relative abundance of travelling with non - public transport means, caused to reduce 21-23% and in parallel of reduction of travelling with non - public transport means, the amount of produced cars emissions for the CO, HC and NOX pollutants has been decreased 39, 36 and 30 percent in relation to the usual mode of implementation of the Odd-Even plan within its range, it will be reduced.

The importance of the role of Information in the Supply Chain and the Position of Transportation and Logistics as Economic drivers of Countries, has led to the integration of Information and Communication Technology and Transportation and the formation of Intelligent Transportation Systems (ITS). The effectiveness of freight and passenger transportation Systems depends on the optimization and correlation of ITS with other systems, including Business Intelligence Systems. The main purpose of this study is to develop a conceptual model to investigate the effect of business intelligence factors on the maturity of this system, which ultimately leads to the effective use of intelligent transportation systems. In order to test the hypotheses, a questionnaire based on literature the subject was designed and distributed among managers and experts of eight government organizations in the country's transportation sector. The results of analyzing the data collected from the sample size, which is based on the Structural Equation Modeling approach, showed that the studied organizations have a suitable level of maturity to implement an intelligent business system. Also, the quality of information content and access to it, flexibility, alignment and integration with other systems positively and significantly affect the success of business intelligence. These results also emphasize the importance of paying attention to technological and organizational business intelligence capabilities.