فهرست مطالب shahin shabani

Due to the traffic structure in Iran and the excessive occurrence of loads to the surface of the pavement and then to the lower layers, the need to implement a resistant layer against to traffic loads in different weather conditions is quite obvious. In recent years, the upward trend in repair and maintenance costs for pavements has been increasing due to the increase in the amount and frequency of traffic loads on pavements, has led to an increase in the tendency to use modified asphalt mixtures, especially in areas with high traffics. Many studies have been done to identify the appropriate additive for use to improve the behavior of bitumen and mixtures. The efficiency and effect of Nano Al2O3 as additive in bitumen and rubberized asphalt mixtures in order to improve their performance against external loads and environmental factors was evaluated in this study. In order to achieve the objectives of this study, bitumen with different percentages of Nano Al2O3 (0, 0.5, 1.0 and 1.5%) was combined and subjected to physical and rheological tests. Also, for evaluating the functional properties of nano modified samples, various experiments were carried out including 4point bending fatigue test and wheel track. The results of this study show that improving the bitumen behavior in moderate and high temperatures can be led to decrease of fatigue and rutting failure in asphalt mixtures. Evaluation on the results showed that using of 20% rubber powder and 1.5% Al2O3 has the best effects on the rheological behavior of bitumen. Also using of this bitumen can improve the asphalt mixture fatigue behavior.

Bitumen and asphalt mixture, cellulose fibers have attracted more attention of researchers due to their lower price and availability; the purpose of this research is to investigate the possibility of using cheap waste materials from paper factories to replace expensive modifiers, which can increase the life of asphalt pavement and reduce the need for its frequent repairs . In this research, the physical properties of the bitumen modified with cellulose fibers and black liquor have been investigated. The results showed that the increase in stiffness of the bitumen containing cellulose micro fibers and liquor. The increase in bitumen stiffness has decreased the degree of penetration and increased the softening point in the modified bitumen. The viscosity of the modified bitumen also increased with increasing stiffness. The results also showed the improvement of the high-temperature performance  of all the samples modified with cellulose micro fibers and liquor. However, the improvement of the low temperature of the modified bitumen is limited to the use of 4 to 6% cellulose microfibers. Increasing the resistance to rutting of the modified bitumen showed the positive effect of using cellulose micro-fibers in order to modify the properties of the base bitumen; Therefore, by using the wastes of paper factories, it is possible to achieve favorable results in reducing the common failures of asphalt pavements, including rutting at high temperature and cracking at low temperature, and reducing the costs of modifying bitumen and asphalt mixtures.

Sliding window is one of the road network screening methods to identify black spots. There are two parameters which are required to be defined by the user: the window length and the minimum number of crashes per black spot. Based on previous studies, changing the window length significantly affects the process of black spots identification. In other words, changing window length and increment length leads to different results. The reviews show that, window length and increment length are selected based on engineering judgment or using the previous experiences, and statistical techniques and scientific methods have not been used. In this research, a new method is proposed based on optimizing the framework of the sliding window method by examining its features. The new method allows the sliding window length to be estimated dynamically. The optimization methodology is as follows: First, the desired road is segmented and for each segment, several different scenarios of window length are selected using the density-based clustering algorithm. Then the safety performance function is developed and the number of predicted and expected accidents and the difference between them as the potential safety improvement is calculated for each window movement for all selected scenarios in the segment. Finally, by calculating average differences using the analysis of variance, the length that has the lowest dispersion of difference values compared to the mean is determined as the optimal length of the window in each segment. The results of this study showed that in all segments, at least in a single movement of the window with the estimated optimal length, the SPF-value of the window has met the desired level of accuracy. Also, by moving the window with optimal dynamic lengths, 122 prone black spots identified, which has more crash density and effective length compared to the results of windows with fixed lengths of 300, 500 and 1000 meters.

The present study aims to identify the inconsistencies resulting from the interferences between the geometric features of the highway, access points and traffic control devices by extracting the frequent association rules and discovering the patterns that contribute to the recurrent crashes. A case study was conducted on a 117-kilometer urban highway around Mashhad. The data for five years of crashes were procured from the corresponding authorities and placed on the network under a geo spatial software environment. Then, the all features of the highway were collected. The trip times between the nodes and existing features were calculated via coding based on the data obtained from one of the route planning software. The operating speed was subsequently estimated. According to the obtained databank and considering the geometric features of the road (horizontal and vertical), the access points, road width, operating speed and position of the traffic control devices (signs and speed control camera), efforts were made to divide the road to the sections. Allocating the crash data to the sections and using the FP-Growth Algorithm, the frequent rules affecting the recurrent crash occurrences were extracted. The results showed that there are different combinations of the geometric road-related factors such as flat-straight alignment and horizontal curve along with cases like right-hand exit, consecutive entrance and exit, and reduced road width in addition to the presence of speed control camera and advanced direction signs on the highway sections together cause inconsistencies like the recurrent crash occurrences.

A key issue to the development of using modified bitumen is the high price of additives, including fibers, which in turn, can increase the cost of bitumen and modified asphalt mixtures. In contrast to other research, in this study, cheap waste materials obtained from paper-making manufacture, including Liquor and cellulose microfibers (obtained from waste pulp mills) are used to improve the properties of modified bitumen while reducing the cost of producing modified bitumen. Further, bitumen modified by styrene-butadiene-styrene (SBS) and styrene-butadiene rubber (SBR) were examined in this study in order to compare with bitumens modified by cellulose microfibers. For this purpose, SHRP tests, including dynamic shear rheometers and bending beam rheometers, were performed on polymer and fiber modified specimens. Based on the results of this study, all modified samples displayed a significant increase in bitumen hardness. Tests of classical bitumen and rotational viscosity demonstrated that polymers of butadiene-styrene-styrene and styrene-butadiene rubber significantly enhanced the viscosity and hardness of bitumen in comparison with other polymers. Consequently, the mix and compaction temperature of the modified samples with these additives have significantly increased. Results revealed that Liquor-containing bitumen improved its high-temperature performance, but it had a negative effect on the bitumen's low-temperature performance. Furthermore, cellulose microfibers had less effect on improving bitumen's properties than polymers such as styrene-butadiene-styrene and styrene-butadiene-rubber. However, cellulose microfibers' capabilities to modify the properties of bitumen, including a lower mixing and compaction temperature of asphalt mixtures than polymers and cheaper production and implementation of asphalt pavements due to the use of cheap waste materials, cannot be overlooked.

Pavement deterioration is a factor contributing to the higher roughness of the road and lower driving comfort in road trips. The pavement roughness measurement has long been an especially important topic to the practitioners. The pavement condition index (PCI) and the international roughness index (IRI) have been applied as two key measures of the quality and performance of the road pavement at the level of project or the road network. Since the pavement condition assessment across a road network by means of the PCI is highly expensive, the present research aims at estimating the PCI based on the IRI to save time and money while evaluating the pavement condition across a road network. For this purpose, we considered three IRI and PCI measurements over main suburban roads in a cold-weather area during a period of 6 years. Firstly, the independence of errors was controlled using the Durbin – Watson statistic, followed by evaluating the normality of the data using the Kolmogorov – Smirnov and the Shapiro – Wilk tests. In order to measure the correlation of the normal data, we used the Pearson’s tests. Results of regression analysis between IRI and PCI showed that the best equation describing their association is a linear inverse model with an R2 = 0.992. A statistical comparison was made between the observed and predicted PCI values and model developed in the present research was further compared to similar research works, exhibiting acceptable agreement of the results.

Identifying the factors that contribute to injury as a result of crashes will help policy makers and road designers implement countermeasures, which could reduce crash injury severity, and cost. In result, objective of this study is identifying factors are more likely to contribute to crashes severity. Today, Researchers have utilized mathematical and statistical modeling-schemes to solve this complex road-safety problem. For this, discrete choice modeling is widely used to model injury severity of the crash. From the models, factors contributing to the injury severity are identified. MNL is the most prominent discrete choice model for modeling crash severity. For modeling, the data of a 5-year period of crashes occurred at the rural roads of Ilam province has been used. The input variables of the model were selected after a significance evaluation test. These variables included Age, Speed, Alcohol, Head-on, Airbag, Ejection, Seatbelt, following too Close, Gender, and Curved. After selecting the variables, the accuracy of the model was also studied. To validate the model, the likelihood ratio and the percent correctly predicted by the model at each crash severity level were used. After evaluating the model accuracy in the prediction of accidents severity, it was found that the model provides acceptable results for evaluating crashes severity, and it was found that except curve and following too close variables, all selected variables contributing in crashes severity.

The shoulder width of the main roads has risen by 35% by revising the Highway Geometric Design. In this research, determination of the effect of simultaneously increasing shoulder width and its paving on decreasing crashes in rural two-way two-line highways was targeted. The studies were conducted in Ilam province highways and the experimental empirical Bayes (EB) method was used. Several highways sections with narrow shoulders paved or non-paved were selected as reference groups and crash data, traffic flow, and their geometry was collected and modeled. Three types of crash prediction model (SPF) were created for the total number of crashes, fatal crashes and shoulder related crashes in the cold seasons (autumn and winter) using the negative binomial regression model for the reference group. Some sections of which shoulders had become safety by widening and paving were also selected as an improved group. To estimate the crash modification factor (CMF), the expected crashes in all improved sections were summed up and then compared with the total number of observed crashes in the period after the countermeasure. The EB method was also repeated twice for the improved group of improving the narrow shoulder to the wide and paved shoulder. Once with the SPF for each of the three crash categories, considering the improved group may not be well-matched with the reference group, and once only with the SPF of the total crashes. The results showed that Widening and paving the shoulders affects considerably on the safety of the shoulders related crashes in the cold seasons with CMF of about 0.42 (58% reduction) and the fatal and injuring accidents with CMF of about 0.72 (28% reduction). It can also contribute to a 12 percent improvement of the total crashes of the cold seasons.

Risk analysis of the rail vehicles collision as one of the most important accidents with the rate of nearly 4 percent of the total accidents has always been of great interest especially for the railway safety decision makers. The reason might be revealed while considering the chain of causes and the scenarios of consequences. The superiority of modeling by Bayesian networks method for analyzing the risk of such accidents is that not only the conditional probability of each cause (hazard) as a variable is assessed but also with having any new evidence, the model can be updated subsequently and the consequences can be monitored. The methodology consists of two major categories of qualitative and quantitative parts while the concluded model is a mixture of the two methods. Main causes of a collision are grouped as environmental, signaling and human factors. Resulted model gives the highest probability to the shunting limit signal as a subdivision of the human errors. Evaluating the consequences resulted in the severity of “second degree” based on the Iranian railway accidents severity categorization guideline.

The direct impact of bitumen properties on the performance of asphalt mixtures has made bitumen behavior modification one of the key issues for researchers. Studies in this area have shown that waste Crumb Rubber have positive and acceptable effects on classical behavior of bitumen, but the rheological behavior of bitumen has been less studied. In this study, 8, 12 and 16 percent of Waste Crumb Rubber (#80 sieve size) by the weight of bitumen were used and then SHRP tests including Rotational Viscometer (RV), Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), Rolling Thin-Film Oven (RTFO) and Pressure Aging Vessel (PAV) and SHRP Plus test including Multiple Stress Creep Recovery (MSCR) were performed on the samples .finally the Performance Grade (PG) of bitumens was evaluated by standard method and also by the results of MSCR test. The results showed that with increasing CR percentage, viscosity and high temperature PG increased so that the sample containing 16 percent CR had the highest temperature grade. also aging after RTFO had no effect on high temperature of PG.Increasing the CR had a positive effect on Jnr and increased the elastic behavior and consequently the bitumen's rutting resistance, especially the specimen containing 16 percent CR achieved the H traffic level which included heavy traffic load (10 to 30 ESALs) or slow moving. It also improved the low-temperature performance of bitumen for samples containing 8 and 16 percent of CR. review of the PG map of Iran showed that bitumen containing waste Crumb rubber is usable in most parts of the country

The current research is conducted to investigate the effect of different lights on reaction of customers of unpackaged fresh food (fruit) using neuromarketing method. Considering research objective, it’s an applied study and regarding method it's experimental , because the control and manipulation of variables took place in the laboratory environment. The statistical population of the study includes food customers (fruit) of Rasht city which 10 out of them were selected as statistical sample using purposive sampling method. In data gathering phase, customers’ brain reactions were recorded using electroencephalogram applying OpenBCI processing software with a sampling rate of 512, in the range of 7-13 HZ and 13-30 HZ by two F3 and F4 electrodes, while for each one, 4 steps of 4-second frequency recording were performed. The results of testing hypotheses using Wilcoxon and Kruskal Wallis nonparametric tests in SPSS software showed that according to the values of F3’ alpha and beta (Positive emotions) and F4’ alpha and beta (negative emotions), there are no differences among green, yellow, and red colors in the choice of food. In comparison of average of F3’ alpha and beta and F4’alpha and beta, there were significant difference in each light and the left hemisphere of the brain more involved. So, positive and logical emotions are dominant.

In recent years, the use of Roller–Compacted Concrete Pavement (RCCP) has developed in road pavement due to its great advantages. Adding fibers to RCC can improve some properties of the concrete, including flexural strength, fatigue resistance, crack growth rate, and shear transfer along cracks and joints. Many experiments have shown the advantages of using fiber-reinforced concrete in RCC, but more information is needed about their behavior in cold regions, and especially the exposure to Freeze-Thaw cycling. Investigation and comparing the effect of polymer fibers on the strength and durability of Roller-Compacted Concrete under Freeze-Thaw cycling are the main goal of the present article. Therefore, specimens with weight percentage of fiber equal to 1, 2.5, and 4% (by weight of cement) and fibers of to 5, 20 and 40 mm lengths are made. Durability test against a Freeze-Thaw cycling and compressive strength are measured on samples after 7, 28 and 90 days. Analysis of the results shows that the additive fiber increases the compressive strength of the RCC, but decreases its durability against the melting and freezing cycles. Therefore, the use of fibers on RCC in cold regions should be done due accuracy and attention.

In this research, the effectiveness of installing night lighting in rural roads was evaluated. To this end, a number of rural roads of Ilam province have been selected. Two axes have been selected as the counter group and two axes as the comparison group. Crash data of four years has been collected. The collected data is analyzed according to before and after study with comparison group for studying crash reduction and benefit/cost method for economic analysis. For accurately estimating the effectiveness, the predicted crashes on improved and comparison sites were used. These predictions were done using the prediction model of crashes in rural two-way roads, and then the results were calibrated for local conditions using the crash modification factor related to lighting installation and also the model calibration method. By applying different stages of the method, the results show a 28% reduction in the frequency of overnight crashes after lighting installation. The statistical significance test indicates the accuracy of the result at 90% confidence level. The results demonstrate an acceptable effectiveness of lighting installation in reduce overnight crashes. The results of the economic evaluation of lighting installation in this study indicate that lighting installing has been successful in improving safety. The ratio of the benefit to the total cost of lighting installing on two counter sites is 1700 to 1. This value indicates that the benefits gained in Rial value are much higher than the annual costs of lighting installation during a 15-year period and about 1700 times.

Applying the tire rubber powder as an additive of bitumen has been one of the considerable topics for the researches. The use of the recycled tire rubber as a measure for protecting the environment moreover the considerable improvement in the bitumen performance and cheaper than the other polymers make the topic more important. In this research, in addition to the tire rubber powder, it has been tried to use the asphalt recycled from reclaimed asphalt pavement as an alternative for replacing bitumen. So, a sample of rubber modified bitumen was prepared and combined with different percentages of the recycled asphalt and tested. The aim of the tests has been examining the rutting and fatigue performance of the bituminous binder by the newer methods such as multiple stress creep recovery, temperature and frequency sweep and linear amplitude sweep. The test results showed that adding 15 to 25 percent of the recycled asphalt to the base rubber bitumen has a considerable effect in increasing complex shear modulus and decreasing the phase angle. So, the recycled asphalt improved the elastic behavior of the rubber bitumen and increased rutting resistance of the bitumen. But, the fatigue resistance of the rubber bitumen was decreased.

Summary Stripping is a common distress occurring on asphalt pavements. The source of this stress comes from moisture, thus, stripping and moisture damage are often used interchangeably. A common way to identify these failures is drilling and coring from road surfaces, and doing destructive tests. The most commonly used tests are bulk density, comparing indirect tensile stress in saturated to dry condition (TSR) , and finding air void percentage .These tests are destructive, and take time more than usual. In addition, we must repair and patch the asphalt pavements where drilled and cored. Ground penetrating radar (GPR) is a method, which is not only a non-destructive method but it also evaluates the roads continuously and provides us with results much quicker than the common destructive tests. In this study, parts of the road networks in Tehran are evaluated using GPR, then several points of the road surface are drilled and cored. Finally, the results of the GPR measurements and destructive tests are analyzed and compared with each other.
Introduction Moisture damage is a common distress that occurs in asphalt pavements. In this phenomenon, adhesion between bitumen and aggregates is ruined. It usually happens where the level of underground water is high, and it is seen along the wheel paths. Stripping starts at the sub base layer, and moves to the upper layer until it appears on the surface. This problem often occurs in the moisture condition when the pavement temperature increases. Cracks appear where traffic is heavier. Finally, it causes holing and showing.
Methodology and Approaches In this study, parts of the road network in Tehran (namely,Amir Kabir Boulevard) were evaluated using GPR, and then, several points of the road surface were drilled and cored. The cores were tested, and as a result, bulk density, TSR, and air void percentage were obtained. Finally, the analysis results of the GPR and destructive tests in different depths were compared.
Results and Conclusions As the amount of asphalt bulk density increases, the air void percentage decreases to less than 7%, and the TSR reaches over 0.8. Stripping is observed where dielectric constant becomes less than 5.10 in the upper 5 centimeters of asphalt depth, and also, stripping happens in the upper 10 centimeters of asphalt depth where dielectric constant reduces to less than 5.40.

Traffic accidents and casualties caused by it are one of the current challenges of human societies, which impose many economic costs on countries. Determining the risk of accidents in the network of roads can be one of the basic steps for assessing the safety of the network and identifying full of accident parts. The most important damage caused by accidents is the death casualties. Therefore, determining the risk of accidents based on the risk of casualties is an effective way to focus on the most critical parts of the roads network. The purpose of this study is to determine the criteria for accepting the risk of casualties in out of town highways. The risk of casualties was also determined by the number of deaths, the annual average daily traffic volume, the length of time examined and the average number of occupants of vehicles. Accordingly, the rate of death of the out of town highways was determined by the three reference societies and then compared with the criteria of quality-rate control method, average kill rate, mean plus standard deviation of deaths rate and twice the death rate and were identified full of accident parts. Comparison of the results of the criteria showed that the average criterion, as well as the standard deviation of the rate of deaths due to executive and credit constraints and the necessity of addressing the most critical parts, is a more appropriate criterion for the current state of the country's roads.

A layer of rubber surface in an aircraft will be separated by takeoff and landing in flight surfaces and these layers stick to the surface of the runway and by repetition, the thickness of these layers increases and improves lubrication and reduces the effect of signs on flight surfaces. In this paper, we prepared a diagrammatic presentation of test in the friction between eastern and western parts of the flight. Average values of friction of each of the three sections of the runway, in down stroke and up stroke, were measured once before tire removal operation and the second time after the tire relaxation and the exploitation rate index and minimum quality of flight surfaces were determined and then compared with the values and standards of the Federal Aviation Organization ICAO and international aviation regulations. The results show that the average coefficients of friction before removal of the tires, to the eastern part and the western part are 0.31 and 0.63, respectively which are lower than standard rates in comparison with standard values. And along with removal of tires, according to the minimum number of daily landings in runway of Imam Khomeini airport friction test should be measured every 4 months. Also, after tire removal, friction test should be carried out again and average friction coefficients for eastern and western parts were measured to be 0.72 and 0.67, respectively which were obtained after comparison with standard values.

Travel time and delay prediction plays a significant role in prevention of engaging road users with heavy traffics and subsequently increasing their confidence in traffic facilities. In the present study first of all by using the data obtained from data collection system of Tehran Traffic Control Organization, the main database to predict BRT bus travel time is established. Therefore Frhngsra-Azadi BRT line has used as a sample. In the conducted modeling, the support vector machine’s regression analysis along with the principal component analysis is used. By using the stated method, travel time in sample is predicted and the results are discussed and compared. The results show that support vector machine’s regression analysis along with principal component analysis has a high accuracy in predicting the intended purpose and has been able to improve the related results for prediction of transit travel time. Therefore the presented method in this study can be used in practical applications and play an effective role in travel time programming of BRT.

Accurate traffic forecasts has important role in providing real-time data traffic, reduce congestion on the roads and improve traffic safety. In this study, a combination of multi-layered back propagation neural networks to predict the peak hour traffic flow with wavelet transform is used. According to the proposed method, using the wavelet transform, a pre-processing is done on the data volume traffic flows to obtain more detailed information about the dynamics of the problem; then as intelligence, training and testing data is presented to the neural network. Trained network using validated assessment functions and to predict the peak hour traffic volume may be used during the next week. Predictions made to measure, traditional back propagation neural network design and compared the results with the proposed method. The results show that the proposed method, the peak hour traffic flow with higher precision than conventional neural network predicts. The method proposed in this study has been done on the basis of parameters and can be used in practical applications.

Road transportation by way of automobiles is a very convenient means of transportation. Today, the most detrimental consequence of developing transportation systems in a country is traffic accident that places a huge financial burden on society. This paper investigates the role of information systems in transportation safety that leads to improved planning and operation of the transportation system through the application of new technologies. Current methods for identification of segments of roads with high potential of accident are based on statistical approaches. Since there are not accident records for newly built roads, these methods cannot be used for regional roads that are recently built. This paper presents a GIS based Neuro-Fuzzy modeling for identification of road hazardous zones. The results of proposed approach are compared with statistical methods. It is shown that this method is a cheaper but at the same time robust means of analyzing the level of hazard associated with each road segment under consideration, specially when data are uncertain and incomplete.