JOURNAL OF TRANSPORTATION RESEARCH
Year:2005 | Volume:2 | Issue:3|Papers Count:6

Air cooled blast furnace slag is a by product made of gradually air cooled molten blast furnace slag and is often stored in stockpiles near the iron mills and usually occupy a wide area around the iron mills. From this perspective the further use of these materials can have its own merits. Air cooled blast furnace slag can be used in asphalt mixtures because of their proper frictional properties. This research is conducted to investigate the effect of air cooled blast furnace slag on technical characteristics of asphalt mixtures and compare the results with the traditional asphalt mixtures. Two series of Marshal and Texas Boiling Tests were carried out in the laboratory. Three types of aggregates (air cooled blast furnace slag, siliceous gravel, lime gravel) with two types of dense graded and open graded were used. The frictional properties of the asphalt mixed with air cooled blast furnace slag materials were evaluated by using the British Pendulum, and the Sand Patch Method. Resistance to moisture was also determined in accordance to Texas Boiling Test. Results showed that by increasing percentage of air cooled blast furnace slag in asphalt mixtures, Marshall Stability, flexibility and skid resistance augmented. Also Texas Boiling Tests indicated that asphalt mixtures have a good resistance to stripping.

In specified limits of weather and sea conditions, the term optimum transportation is used to address maximum safety and crew comfort, minimum fuel consumption, minimum time underway, or any desired combination of these factors. Before defining such a goal function to optimize the transportation, one has to know about the ship reaction in waves. In other words, ship motions evaluation in different sea conditions is the base of ship routing.In this paper slamming rules as an important criterion in ship motions and its probability is investigated and predicted. By applying different motion's constraints, evaluation of ship motions is also applicable. Limitations in maximum vertical acceleration of bridge and maximum roll angle are considered as the main criteria and speed polar diagram is plotted according to such restrictions. This yields the regions with minimum risk of damage and maximum safety. It must be remembered that the general method presented here, is also applicable for other sea keeping criteria and all types of floating bodies.

Improper location of airport may cause human and property losses. In this research, an attempt has been made to develop an airport site selection model using the permutation methodology. In this method, the most widely accepted site selection criteria for an airport are taken into account. Different alternatives and scenarios are analyzed and the optimum one is selected by using the developed model. The human errors in the process are minimized. More over, the site selection process would not be time consuming. It is also possible to change the number of variables effective in the airport location within the site selection process.

Road maintenance and management is one of the most important tasks for road administration in every country. Application of preventive maintenance has been the subject of research for several years. Chip Seal is an option in preventive maintenance reducing the cost and time of rehabilitation. The outcome of the previous researches has revealed that spending a small portion of total cost for maintenance resulted in reduced pavement rehabilitation costs.In this paper after introducing and identification of chip seals, the design and construction of different chip seal is presented. The main purpose of this research is introducing different type of chip seal and evaluating their performance in the laboratory. To fabricate the chip seals effort was made to use the facilities available and simulate the real conditions in the country. In this research, friction, permeability and coating properties of different chip seals was evaluated to make a comparison between different chip seals.

Informing of demand elasticity not only increases the decision-making and selection power of service providers but also addresses the ability of supplier flexibility (including rail service supplier) vis-a-vis material providers. If Railway organization has information on the effect of main factors in the final rail service demand and their elasticities, it will have proper contexts of decision-making about infrastructure and access pricing. In this paper, it is tried to review the studies on passenger and cargo demand elasticities in different countries and estimate various models for rail transport demand. In these models, passenger and cargo demand are functions of price (fare), the price of alternative mode of transport, population, production volume and sectoral value-added and so on. The estimated elasticity values are compatible with similar studies to high extent. They indicate inelastic (non-sensitivity of quantity to price) rail travel demand with respect to fare, distance and population and substitutability with bus travel. Also, the demand for cargo transit by train is inelastic to distance. In other words, the demanded quantity of cargo is almost constant with relative to distance.

There are vast planes of quicksand in Iran that create many financial losses for the road and railroad projects implemented in these areas, as well as social and hygienic problems for the residents of these areas. Presently -the surface area of deserted and sandy planes in the country is estimated as 34 MH and the deserted areas as 16 MH, amongst which 12 MH is the sandy areas and 5 MH of these areas is the place of quicksand. We are therefore confronted with vast sandy areas that result difficulties in construction of roads and railroads. In this research two types of pozzolanas with different silica and alumina contents have been used in stabilization process of sandy soils and the effect of silica and alumina on the ultimate compressive strength and curing time required for strength gain have been studied and the results are concluded in the paper.