In general, the physical and rheological properties of asphalt binder are directly affecting resistance mix to permanent deformation (rutting), water damage, thermal cracking. The degradation in these leads severe distresses that appear pavement and, consequently, make repair maintenance very expensive. Since modified-asphalt cement may help minimize such aforementioned distresses, this researc...

The fuel resistance property plays an important role in asphalts, but available standards for determining this characteristic are presently lacking. In the present work, a number of polymer modified bitumen with styrene-butadiene-styrene (SBS) polymer (4, 5, 6% SBS) and SBS/ sulfur modified bitumen with various percentages of sulfur (1.65, 3, 3.5% based on polymer content) were prepared. Each s...

This study reports the simulation of a photocatalytic system process and the photocatalytic property of self-cleaning asphalt concrete (SCAC) with four typical asphalt mixtures. A photocatalytic system was simulated based on the pollutant concentration data, which were collected on three types of city roads. Two photocatalytic indexes were proposed to evaluate the photocatalytic property of sel...

Waste utilization has gained more and more interest. In this study, crumb rubber and diatomite were used to modify asphalt binder and the short-term aging effects on the properties of modified asphalts were evaluated. Three kinds of modified asphalt were prepared; they are diatomite modified asphalt (DA), crumb rubber modified asphalt (RA), and diatomite and crumb rubber compound modified aspha...

water erosion causes severe soil damage in northern forests of iran which is associated with different rut depths in skid trails. the aim of this study was to assess rutting and soil displacement on skid trails to mitigate water erosion. therefore the research was carried out in eight parcels of district no 3 of shafarood forest in the north of iran. in order to evaluate the amount of erosion i...

It is well known that the performance of hot mix asphalt (HMA) in service life is closely related to a proper aggregate gradation. A laboratory study was conducted to investigate the effects of nominal maximum aggregate size (NMAS) on the performance of stone matrix asphalt (SMA). The volumetric characteristics and performance properties obtained from wheel tracking tests, permeability test, be...

Bovids represent a convenient group for studying the acoustical variation, functions and evolution of vocal communication. Among bovids, a wide spectrum of vocal adaptations and examples of parallel evolution with cervids and humans can be found (Fitch & Reby 2001; McElligott et al. 2006; Frey et al. 2007, 2008a,b). For instance, in the goitred gazelle (Gazella subgutturosa), a strong sexual di...