This study aims to predict the Dynamic Load Coefficient @LC) 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 DLC's value is typically in the range of 0.05-0.3, and close to zero when the truck's wheels are moving over a perfectly smooth road. To achieve the objectives of this study, which is to determine the DLC's 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 tmck, 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.
Abstract. 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 Superpave™ 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.
Warm Mix Asphalt (WMA) represents the technologies that allow the reducing of asphalt binders’ mixing and compaction temperatures by reducing its binders’ viscosity. This paper gives a comprehensive chronological review from prior researches and practical experienced among researchers and industrial practitioners while implementing WMA technology including constituent materials, mix design and mechanical performance issues. Within this, the problems and benefits as well as different types of WMA additives were clearly identified as essential for a better understanding of the application of WMA technology in pavement constructions.
In order to improve the performance of asphalt mixture, the virgin asphalt binder needs to be modified with suitable modifiers. There are various types of modifiers available in market and it is clearly stated and established in most of pavement standard specification. Nowadays, pavement technologist and researchers had put their interests on nanotechnology and they had found that polymeric nanocomposites have shown its effectiveness through the modification of virgin asphalt binder with certain portion of nanomaterials. In addition, many studies have demonstrated that nanomaterials have significant effects in improving the engineering properties of asphalt binder and mixture. Therefore, a thorough literature review on the current research of nanomaterials in pavement engineering for the past decades can enhance understanding and guaranteed something beneficial findings in the future. This paper described the theory of nanotechnology and its historical development including the method used among researchers in evaluation the structural and morphological characteristics of modified binder with nanoparticles. Also, the effect of different types of nanoparticles, suitable dosages, modifying procedures, problems and benefits on asphalt binder and mixture were explained. It is expected that in future the implementations of nanotechnology would have major impacts for better pavement performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.