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Showing 2 results for Asphalt

Mohammad Barati, Mohammad Zarei,
Volume 1, Issue 1 (9-2017)
Abstract

Asphalt, this wonderful mixture that all of us deal with it every day. Perhaps the engineers in this domain as one of the solution have placed the modification of technical properties of asphalt on top of their activities for improvement of the features of this wonderful mixture. Modifying the technical properties of bitumen and asphalt has created many study opportunities all around the world. Along with it and in this article at first, with adding carbon nanotube with the amounts of 0.25, 0.50, 1 and 1.5 weight percent of base bitumen, the effect of this additive on mechanical properties of asphalt mixture was studied. In the continuation, the asphalt samples amplified with carbon nanotube for doing the Marshall Test were evaluated and tested. The results indicated that this additive causes to change in the Marshall test parameters such as increase of strength and reduction of flow. On the other hand, the special weight of asphalt mixture has faced with increase and the void space percent of aggregates faced with relative reduction. Also the void space percent of asphalt mixture and the percent of void space filled with bitumen were increased relatively. In the economic study of the effect of carbon nanotube on mixture, it was concluded that with gradual increase of carbon nanotube, the economical advantage of the project is reduced. Finally, with regard to the obtained results and analysis of the effect of this material on the bitumen and asphalt properties, it was concluded that this additive can be used in the regions with warm climate with heavy traffic and in the limited regions.

Farzin Farooghi,
Volume 1, Issue 2 (12-2017)
Abstract

In these studies, the effect of the load types on the stress and the deformation created in the hot-mix asphalt and its lifetime in different qualitative conditions of the surface contact of the layers has been investigated. For this purpose, we have used a set of rules in Iran and France codes. In Iran, the weight of the single-axle load 80 kN and in the French Code the weigh of the dual-axle load is 130 kN. Linear elastic method has been used in structural analysis and fatigue failure and rutting failure has been used to investigate the lifetime of structure. In these studies, the effect of the layer thickness and the two types of contact surface quality (adherence and Non-adherence) are considered. One of the most important results of this study is the significant increase in the vertical strain of the subbase course and horizontal strain of the base course due to single axel load compared to the dual axel load. Inappropriate quality of the layers has increased about 50% of the settlement in the pavement. Also, the effect of single axle load increased about 45% of structural settlement and decreasing of the base and surface courses thicknesse has increased about 30% seattlement in the pavement structure.


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