Ratnasamy Muniandy

An overview of the emerging warm mix asphalt technology

The asphalt industry is constantly attempting to reduce its emissions as concerns are growing on global warming. This is done by decreasing the mixing and compaction temperatures of asphalt mixtures without affecting the properties of the mix which is possible through numerous available technologies in the industry. The production of asphalt mix is done by warm mix asphalt (WMA) technology at considerably lower temperatures (120°C or lower). Less energy consumption, lower mixing and compaction temperatures, early site opening, reduced ageing, fewer emissions, cool weather paving, better workability and, finally, an extended paving window could be mentioned as some of the benefits obtained by using the WMA. This paper presents the WMA techniques and technologies such as foaming techniques, wax and chemical additives techniques. Additionally, the performance of WMA popular technologies such as Sasobit®, WAM®-Foam, Evotherm®, Low energy asphalt, Rediset® WMX and REVIX™ are fully described.

Pavement rehabilitation and maintenance prioritization of urban roads using fuzzy logic

With regard to limits in budget, inevitably, one must choose prioritized projects in pavements rehabilitation and maintenance process. This paper looks into prioritization based upon a model including all effects of important factors like pavement condition index, traffic volume, road width as well as rehabilitation and maintenance cost. Since defining a model that introduces all those factors was difficult, a more advanced modeling named fuzzy logic was referred for the problem of prioritization. Although analytical hierarchy process can be used for decision making process as well, fuzzy modeling lets one have more precise choices for the outcome. Finally with the help of MATLAB software and coded M-files, inference engines such as Product engine, Dienes-Rescher and Lukasiewicz were all tested and the logical favorite separation for this application was found in product inference engine. As a case study some streets located in district No. 6 of Tehran municipality were selected and the favorite mathematical model was executed on those streets. This model was used for prioritizing these 131 sections.

Rheological Property Investigation of Various Sasobit-modified Bitumen

Sasobit has gained interest as an alternative over polymer modification due to its capability of reducing energy requirements for asphaltic mix construction. A study was conducted in order to investigate the effect of different blending speeds on the rheological properties of bitumen at intermediate temperatures. Higher values of revolutions per minute speeds showed an increase in viscosity, softening point temperatures, and complex modulus values. Therefore, it was concluded that the overall stiffness of the tested binders were due to the partial aging of binder. Overall, the service life of pavements will reduce due to the occurred aging.

Motorcyclist Rear Brake Simple Perception–Response Times in Rear-End Collision Situations

Objective: The purpose of this study was to determine the baseline motorcycle riders’ perception–response times (PRTs) in an expected object braking task and to determine the significant difference between PRTs of older and younger riders. Methods: Fifty-nine participants sat on their motorcycles in exactly the same way as they would when riding and then they awaited activation of the taillights of the passenger car (parked) in front of them. PRTs of the motorcyclists were transcribed from the camcorder when the riders hit the brakes as quickly as possible following the activation of the cars brake lights. Results: Results of PRT were calculated by taking the average of both male and female older and younger riders. The study demonstrates that the mean and standard deviation of the motorcycle baseline PRTs are 0.44 and 0.11 s, respectively. Riders’ age and gender were not found to be significant variables for PRT. Conclusion: The mean of baseline perception–reaction time of motorcycle riders is smaller than that of passenger car drivers. If traffic facilities are designed based on passenger car drivers’ simple perception–reaction times where drivers are generally more alert (for example, in traffic signal design), they can provide the required PRT for motorcyclists. This suggests that the utilization of more powerful brake lights on motorcycles could be highly effective for preventing rear-end motorcycle collisions.

A Laboratory Investigation on the Rheological Properties of Aged and Unaged Organic Wax Modified Asphalt Binders

Different proportions of Sasobit (Sasol Wax, Hamburg, Germany) content were blended with 60–70 penetration grade asphalt binder type and were subjected to physical and rheological tests in order to determine the influence of Sasobit on asphalt binder. The test results indicated that Sasobit had different effects on temperature susceptibility of binders. Frequency sweep test showed that binders containing Sasobit had higher complex modulus compared to the control binders. In addition, lower phase angle values were observed for Sasobit-modified binders. FTIR analysis showed changes in the microstructure and weight distribution of Sasobit-modified binders.

Motorcycle Characteristics for Sight Distance Investigation on Exclusive Motorcycle Lanes

In developing Association of Southeast Asian Nations (ASEAN) countries, the motorcycle is a popular means of transportation because it is cheap and provides flexible door-to-door mobility. However, motorcyclists are also highly involved in road accidents. Separating motorcycles from other vehicles in traffic by providing motorcycle lanes is a good engineering measure to improve the safety of motorcyclists. In designing motorcycle lanes, considerations of geometrical elements such as horizontal and vertical curve lengths, stopping distances, and passing sight distances are essential. This study attempts to quantify the eye levels and head levels of motorcycle riders and motorcycle headlight and taillight height characteristics that influenced these geometrical elements. Characteristics of the motorcycles observed along the existing exclusive motorcycle lanes in Selangor state of Malaysia were transcribed from a camcorder, using reference dimension. Findings recommend a design motorcycle eye height of 1,350 mm (5th percentile), headlight height of 800 mm (5th percentile), and taillight height of 625 mm (5th percentile). A motorcyclist height of 1,525 mm (10th percentile) is recommended for the design of sight distance. Recommended heights reduce the cost of motorcycle lane construction with demonstrated safety compared with the current criteria.

DEVELOPMENT OF OBSTACLE AVOIDANCE TECHNIQUE IN WEB-BASED GEOGRAPHIC INFORMATION SYSTEM FOR TRAFFIC MANAGEMENT USING OPEN SOURCE SOFTWARE

The shortest path routing is one of the well-known network analysis techniques implemented in road management systems. Pg Routing as an extension of Postgre SQL/Post GIS database is an open source library that implements the Dijkstra shortest path algorithm. However, the functionality to avoid obstacles in that analysis is still limited. Therefore, this study was conducted to enable obstacle avoidance function in the existing pgRouting algorithm using OpenStreetMap road network. By implementing this function, it enhances the Dijkstra algorithm ability in network analysis. In this study a dynamic restriction feature is added at the program level to represent the obstacles on the road. With this modification the algorithm is now able to generate an alternative route by avoiding the existence of obstacles on the roads. By using OpenLayers and PHP a web-based GIS platform was developed to ease the system’s usability.

An effective road management system using web-based GIS software

Recently, there is a rapid development of road transportation network. This situation arises due to the number of vehicle on the road that keeps increasing year by year. Thus, this will increase the possibility of dangerous situations to the road users if roads are not being maintained appropriately. Therefore, in order to keep the road in safe condition, the road management activity should be improved. A complete system for road management has been applied in the developed countries for the past decades. However, the usage of application programming interface (API) from GIS software has limitation to make modification in terms of interactivity of the system. Open source software was proposed as a way to assist in reducing the development cost of developing road monitoring system. In this paper, open source software was proposed as a way to assist in reducing the development cost in developing road management system. OpenLayers framework was used as map rendering platform. The system can be used by administrator of road network to update the road information. At the same time, it can be used by the road user as well to view the information regarding road-related incidents.

CHARACTERIZATION OF EFFECTIVE TIRE CONTACT AREA FOR VARIOUS TREAD PATTERNS

The effective tire-pavement contact area affects the relative damage of asphalt pavement and should be incorporated in both mechanistic and empirical response analyses of pavements. A new machine called ROTOCOM Wheel Tracker (RCWT) was designed and fabricated to capture the effective tire contact area apart from slab compacting, and conducting simulative laboratory wheel tracking tests. The main focus of this paper is laboratory measurement of effective tire contact areas for various tread patterns. Seven tire treads were selected for the footprint image analyses at five tire loads and four tire inflation pressures. An image processing MATLAB-based program was coded to calculate the contact areas of the 280 imprints obtained from both sides of the RCWT. Factorial analysis indicated significant effects of tire tread, tire load, and inflation pressure on the resulting contact area. Comparison between effective and traditional contact areas indicated that the current pavement design procedure with traditional circular contact area extremely overestimates the actual tire-pavement contact area up to 92%.

Optimization of Ground Penetrating Radar (GPR) Mixture Model in Road Pavement Density Data Analysis

This paper presents an optimization of GPR mixture model based on the measurements and simulation results at frequency range of 1.7-2.6 GHz. The purpose is to get a most accurate relationship between attenuation and density for various road pavements densities. The proposed method is simple, fast, nondestructive and accurate way to determine the density of road pavement. Density is a one of the important parameter in order to determine the compressive strength of road pavement. In laboratory, a few of received signal strength and measured attenuation for nine road pavement slab samples were taken at four different frequencies. The GPR mixture model has been used to produce the predicted attenuation due to the pavement density. The calculation and selection of mixture model has been discussed thoroughly and only the best performance of GPR mixture model was selected for optimization.