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Fazaeli H.,Iran University of Science and Technology | Behbahani H.,Iran University of Science and Technology | Amini A.A.,Iran University of Science and Technology | Rahmani J.,Iran Ministry of Road and Transportation | Yadollahi G.,Technical and Soil Mechanics Laboratory
Advances in Materials Science and Engineering

This paper presents the results of an experimental research on the effects of Fischer Tropsch-Paraffin (Sasobit) content on physical and rheological properties of Sasobit modified bitumen at various operational temperatures. For this purpose, bitumen with a Performance Grade (PG) of 58-22 is selected as the base and later it is modified with 1, 2, 2.5, 3, and 4 weight percent of FT-Paraffin (Sasobit). The performance of modified bitumen at high, intermediate, and low temperatures is evaluated based on Strategic Highway Research Program (SHRP) Superpave tests. Results of the study show that FT-paraffin improves the performance of bitumen at high temperatures in addition to increasing the resistance of mixture against permanent deformation. Despite the advantages of FT-paraffin on bitumen performance at high temperatures, it does not show a considerable influence on the intermediate and low temperature performance of bitumen. The effect of FT-paraffin content on the viscosity of modified bitumen is also investigated using Brookfield Viscometer Apparatus. Results show that increasing the additive content lowers the viscosity of modified bitumen. This in return can reduce the mixing and compaction temperature of asphalt mixtures. Copyright © 2012 Hassan Fazaeli et al. Source

Abbasghorbani M.,Technical and Soil Mechanics Laboratory | Ziksari A.B.,Technical and Soil Mechanics Laboratory | Shoormeij E.,Technical and Soil Mechanics Laboratory | Brazvan S.,Technical and Soil Mechanics Laboratory
International Journal of Pavement Research and Technology

Riding comfortablyand safely throughhorizontal curvesin roadwaysshould be provided by superelevation. Asphalt overlaying during the maintenance period could change superelevation (reduce or reverse it);thus,assessing a road’scross slope along curves is of great importance. In this research, the Road Surface Profiler (RSP) device was used to measure superelevation at a curve in a newly constructedShahroud-Miami roadway. It was chosen because of the availability of curve parameters such as start/end points, radius, superelevation, and design velocity. A good agreement was found between superelevation measured by RSP and that of the curve design. Also, it was found that rate of turn (RT) profileis a suitabletool to determine the start/end points of curves,which is abasic step in assessing curve superelevation. Three horizontal curves of Andimeshk ring were then tested by the RSP device and analyzed based on findings from the curve in Shahroud-Miami. Results show that all three curves haveasuperelevation shortage of approximately 3%. In these cases, the temporary solution is to install a new "Posted-Speed" sign based on existing curve superelevation. © 2015, Chinese Society of Pavement Engineering. Source

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