Les isothermes d'adsorption du phŽnol et du 4-chlorophŽnol en solution dans l'eau sur des asphaltnes floculŽs en masse et sur des asphaltnes dŽposŽs sur de la silice ont ŽtŽ dŽterminŽs par analyse chromatographique frontale ˆ 293, 298, 303 et 308 K. L'adsorption sur des asphaltnes floculŽs en masse Žtait la plus importante avec des isothermes correspondant ˆ un mŽcanisme de Freundlich. La qu...

This study examines the effectiveness of HMA overlay design strategies for the purpose of controlling the development of reflective cracking. A parametric study was conducted using a 3D Finite Element (FE) model of a rigid pavement section including Linear Viscoelastic (LVE) material properties for the Hot Mix Asphalt (HMA) overlay and non-uniform tire-pavement contact stresses. Several asphalt...

Rutting of flexible pavement is considered one of the major pavement distresses noted around the world and in Egypt. Many investigators showed at about 55 to 80% of rutting occurred in the surface layer. Rutting of asphalt surface layer may be due to many causes happened during construction phase and service phase. The main objectives of this research are to evaluate the impact of aggregate gra...

The accumulated irreversible deformation in pavement under repeated vehicle loadings will cause fatigue failure of asphalt concrete. It is necessary to monitor the mechanical response of pavement under load by using sensors. Previous studies have limitations in modulus accommodation between the sensor and asphalt pavement, and it is difficult to achieve the distributed monitoring goal. To solve...

The three major distress conditions affecting the performance of asphalt pavements are permanent deformation or rutting, fatigue or load associated cracking, and low temperature or thermal cracking. In an earlier technical topics article (Fall, 1998), we examined the causes of fatigue cracking and the importance of good compaction during construction to help minimize this type of distress. In t...

Recently, the Human Bitumen Study has been finished (Schlüter, 2011). Including 500 workers from more than 80 construction sites it represents the world-wide largest study on adverse health effects caused by bitumen. The study answers a question that has been controversially discussed since decades: Bitumen exposed workers do not show higher levels of DNA damage than unexposed individuals. On t...

OBJECTIVES To characterize temperature-dependent emissions from paving and built-up roofing asphalt (BURA) and to quantify differences in temperature-related concentrations and composition. METHODS Using headspace gas chromatography, 18 polycyclic aromatic hydrocarbon (PAH) emission concentrations were quantified over eight temperatures (120-315°C) for paving asphalt (n = 20) and Types II, II...

rutting in asphalt concrete is a very common form of distress in asphalt concrete pavement which unfortunately has been incurable to date. one of the prime reasons of rutting is attributed to the behaviour of asphalt binder at elevated temperature. this study has investigated the performance of polypropylene fibres modified asphalt concrete mix against rutting. two types of asphalt concrete sam...

polymer application for the improvement and modification of the bitumen used in roads surfaces has expanded in recent decades. the roads engineers and constructors, therefore, have used the modified bitumen in asphalts helping in this way to increase roads and pavements service life and improving the durability of the roads and asphalts. the bitumen used in asphalt mixture constitutes only a lo...

IN T R O D U C T IO N The major material utilized in the construction of the roads, streets and highways of this country is asphalt. Of the nation’s 3.84 million miles of roads, 1.86 million are paved, hard-surfaced structures. 1.74 million or 94% of these paved roads are constructed of asphalt (Fig. 1). Likewise, within the state of Indiana, 83% or about 9300 miles of the 11,200 miles under th...