Rosnawati Buhari

Short term and long term aging effects of asphalt binder modified with montmorillonite

Nowadays, most of asphalt used in pavement construction is produced from petrochemicals through refining process of crude oil. When evolves with time, asphalt become stiffer and brittle due aging process. In this paper, the rheological effect of short-term and long-term oxidative ageing of asphalt binder modified with montmorillonite (MMT) was studied using SuperpaveTM rotational viscometer (RV), dynamic shear rheometer (DSR) and Fourier transform infrared (FTIR) instruments. The results indicate the addition of MMT increased the viscosity. Based on dynamic mechanical analysis with DSR, MMT modified binder has a potential to increase rutting and fatigue resistance. In terms of FTIR test, it appears that the chemical bonding had changed in the asphalt binder before and after RTFO and PAV aging which suggest that the additional of MMT could delay the aging process.

Dynamic Load Coefficient of Tyre Forces from Truck Axles

This study aims to predict the Dynamic Load Coefficient (DLC) of tyre forces from truck axles. Dynamic Load Coefficient is frequently used to characterise the dynamic loads generated by axles. It is a simple measurement of the dynamic variation magnitude of the axle load, for a specific combination of road roughness and speed. Under normal operating conditions, the DLCs value is typically in the range of 0.05-0.3, and close to zero when the trucks wheels are moving over a perfectly smooth road. To achieve the objectives of this study, which is to determine the DLCs value for seven different types of axles, a simple validated quarter-truck model was excited by a random road surface profile, in order to simulate a vehicle-road interaction. Points are equally spaced along the simulated road to generate dynamic loadings over a broad range of truck speeds. Multiple trucks gross-weight conditions were used to present realistic traffic behaviour. The results showed that irregular road profiles, exciting the vehicle as it travelled, caused continually changing tyre forces. Also, dynamic loading was seen to be fundamentally influenced by the type of suspension (i.e., air and steel), loading condition, and vehicle speed. For example, the DLC value of the tyre forces of the quarter-truck fitted with a steel suspension was found to be more than twice that of the truck fitted with an air suspension. Tyre forces of the one-third laden truck were more aggressive than any other loading condition, due to the uncertain body-bounce generated by the truck, which was strongly dependent on surface irregularities. At low speed, the DLC was greatly decreased if the load was increased. Furthermore, DLC value was always lower for trucks with air suspension over steel suspension, for the same load and vehicle speed. However, air suspension efficiency was clearly better for higher axle loads.

Car Driving Behaviour on Road Curves : A study Case in Universiti Tun Hussein Onn Malaysia

The World Health Organization (WHO) predicted that in 2020, road accidents will become the third cause of deaths in the world. Several factors contribute to road accidents, among them are human error, speeding, irregularities in road design and period of driving (either nighttime or daytime). In road design, horizontal curves are of particular interest to the designer, given that accidents are very likely to occur at such locations if drivers lose control of their vehicles due to inappropriate speed choices. This study was conducted to investigate the variation of driving behaviour on horizontal curves. The test car was fitted with a Global Positioning System (GPS) device and driven by 30 participants. The research findings show that drivers’ choice of speed varies while approaching horizontal curve, on the curve and just after leaving the curve. Apart from this, although drivers were found to have driven at a slightly higher speed during daytime compare to evening driving, however the difference was not significant. A comparison between genders also revealed that female and male drivers drive at similar speed behaviour

Predicting Truck Load Variation Using Q-Truck Model

The study of heavy vehicle forces on pavement is important for both vehicle and pavement. Indeed it was identified several factors such as environment, materials and design consideration affects pavement damage over time with traffic loads playing a key role in deterioration. Therefore, this paper presents dynamically varying tire pavement interaction load, thus enable to assess the strain response of pavements influenced by road roughness, truck suspension system, variation of axle loading and vehicle speed. A 100m pavement with good evenness was simulated to check the sensitivity of the dynamic loads and heavy truck vertical motions to the roughness. The most important performance indicators that are required in pavement distress evaluation are radial strain at the bottom of the asphalt concrete and vertical strain at the subgrade surface was predicted using peak influence function approach. The results show that truck speed is the most important variables that interact with truck suspension system and thus effect of loading time are extremely important when calculating the critical.

Damage Equivalent of the Flexible Pavement Variation with Load Applied

Previous research revealed that influence function is strongly influenced the appropriateness of pavement damage prediction and are demanding to be concern in order for better prediction of long term pavement performance. In order to identify the impact of traffic loading condition on the influence function of the pavement toward failure, further stucdy was done to determine the exponential value in the Damage Equivalent Law for varies loading condition and also vehicle speeds. To achieve the aims, the simple quarter truck model was efficiently used with personal computers to predict pavement loading. Towards reality of traffic loading condition will contain a distribution of axles load between unladen and fully laden, the study was further taking into account realistic axle load variation. Results are presented from a study to evaluate the relative influence of truck speed and axle load variation on the stiffness of the asphaltic layer and thus the primary response of the pavement. In conclusion, the exponential value in the Equivalent Damage Law is clearly sensitive to both factor.

Pavement Primary Response Using Influence Function and Peak Influence Function

It was identified in previous research that errors in theoretical damage much associated with the influence function calculation. Thus, this paper present the efficient prediction of primary response due to dynamic vehicle loading using influence function and peak influence function approach. In order to provide the realistic loading condition, dynamic road response model with idealised loads representative by mathematical quarter-truck model with two degree of freedom was excited by a random road surface profile which equally spaced points along the simulated road with various different speeds. Consequently, the simplified computational approach (peak influence function method) was identified only a few points gave a small different compare with the influence function method for along the longitudinal distance. In order to identify the impact of both methods, further implementation was done to calculate fatigue damage (horizontal tensile strain at the bottom of a bound layer) or rutting damage (vertical compressive strain at the top of the subgrade layer) predicted by constant load moving at varies speed. It was found that the differences in response are particularly small and increased steadily as the increasing of the vehicle speed. It was conclude that the simplify calculation was able to predict stresses and strains sufficiently accurately and identified relatively small errors into the pavement damage prediction. Hence the simplification in particular much reduced the computation time sufficiently and minimized the computer resources significantly.

Influence of Ageing Process on Rheological Characteristic of Waste Natural Rubber Latex Modified Bitumen

occurs during the modification and ageing process. The ageing process does consequences in road deterioration; however, it is also benefits in determination of optimum properties during bitumen modification process. Thus, this study was conducted to evaluate the changes of bitumen (unmodified and modified) properties as it was exposed to artificial ageing process. In order to achieve the objective, base bitumen (PEN 60/70) was modified with waste natural rubber (NR) latex. Subsequently, the modified bitumen was subjected to a laboratory ageing process by the aided of rolling thin oven film (RTFOT) and pressure ageing vessel (PAV). Its rheological characteristic was evaluate using dynamic shear rheometer (DSR). It was found that, associating waste NR latex with bitumen improved its properties during short term and long term ageing, indicated by G*/sin δ and G*.sin δ. The performanc

Groundwater Responses on Pumping Analysis for Clayey Aquifer

The relationship between water quantity and clayey layer shows that water storage was very limited to an infiltration into the ground layer which is still retains as a surface water during recharge by precipitation. This paper consists of pumping analysis by using AQTESOLV model in a groundwater response for clayey area to identify the capability of water quantity actions during the discharge and recharge flows. Based to pumping analysis, including type of pump used, discharge rate, water table response, recharge rate, type of soil, and remaining time shows that this area was unconfined aquifer with has low hydraulic conductivity below than 9.6 mm/hr. Therefore, this simulation shows that the quantity and capacity of water intake able to withdrawal more than 40 m3/day by using 1hp pump and above with a constant rate after 4 days pumping continuously. The capability of storage and intake should be considered by natural (rainfall) or man-made recharge to show the water balance in the system whiles the process of pumping continuously. Therefore, this analysis able to predicts the capacity of groundwater storage at the clayey characteristics while it needs to improve any strategy to generate more water intake.

Federal Road Profile Model Generation Based on Road Scanner Data

In Malaysia, the application of Mechanistic-Empirical approach in pavement design guide is still in early stage of introduction and many more researches need to improve it. One of the task needs is generating road profile model to evaluate the dynamic axle loads from vehicles. Therefore, this study aims to generate a few models of road profiles based on the real road profile data called reference road profiles model using mathematical method. The reference road profiles data are a measurement of new paved federal road in Malaysia. A profiles of two section roads (300 m length each) measured by road scanner were determined from Malaysia Public Work Institute (IKRAM). The Profile Viewing and Analysis software (ProVAL) was used to filter unwanted wavelength, visualized the measured road profile data and obtained the road profile International Roughness Index (IRI). Meanwhile, Matrix Laboratory software (MATLAB) was used to generate road profiles based on Dodds and Robson Power Spectral Density (PSD) approximation equation. The calibration between generated and reference road profiles were examined by correlation coefficient value. From the results, all generated road profiles with correlation coefficient value ranges between −1 < ρ < −0.7 or 0.7 < ρ < 1, gives different IRI values with the reference road profile. However, the differences of IRI values are acceptable (less than 5 %). Therefore, all 56 models of generated road profiles are applicable for long term pavement performance. Although, a road profile model with the same IRI value with a reference profile is the most applicable for long term pavement performance.