Nowadays, in addition to materials and components of asphalt mixtures that are bitumen, aggregates and mineral fillers, other materials known as additives or modifiers are also used. These compounds include wide range of organic, inorganic, industrial, and natural materials used in order to reduce deficiencies, to improve the physical properties and to modify some mechanical properties o...

This report presents the results of an investigation of the performance of a variety of materials added to asphalt binders and mixtures to change their properties, particularly with respect to rutting and cracking. The approach included a field trial of seven polymer and particulate modifiers, supplemented by laboratory characterization of the materials used in the field. The modifiers evaluate...

Adhesion between asphalt and aggregate plays an important role in the performance of asphalt mixtures. A low-frequency adhesion fatigue test was proposed in this paper to study the effect of environment on the asphalt-aggregate adhesion system. The stress-based fatigue model had been utilized to describe the fatigue behavior of thin-film asphalt and aggregate system. The factors influencing the...

Millimeter-wave radar-based sensors are being considered for a number of automotive applications including obstacle detection and collision warning, true-speed, and road-surface recognition. In this paper, the interaction of electromagnetic waves with asphalt road surfaces, possibly covered with ice or water, at millimeter-wave frequencies is studied. First, an experimental procedure for determ...

This study presents micromechanical finite-element FE and discrete-element DE models for the prediction of viscoelastic creep stiffness of asphalt mixture. Asphalt mixture is composed of graded aggregates bound with mastic asphalt mixed with fines and fine aggregates and air voids. The two-dimensional 2D microstructure of asphalt mixture was obtained by optically scanning the smoothly sawn surf...

Title of dissertation: Effect of Aggregate Inhomogeneity on Mechanical Properties of Asphalt Mixtures Haleh Azari, Doctor of Philosophy, 2005 Dissertation directed by: Professor Richard McCuen Department of Civil and Environmental Engineering Vertical and radial inhomogeneity of asphalt mixture components in laboratoryfabricated specimens have been of concern in asphalt mixture testing because ...

The ageing of asphalt mixes, together with their exposure to low temperatures, causes a progressive increase of cracking. In this paper, the effect of ageing and temperature on the fatigue of asphalt concretes made with two types of binders, conventional (50/70) and polymer modified bitumen (PMB), is studied. For this purpose, specimens previously subjected to an accelerated laboratory ageing p...

Over the past twenty years; road traffic (both passenger and freight) has grown significantly in Pakistan. Higher axle loads and repetitions have resulted in premature rutting of flexible pavements. Rutting, in the form of shear flow is a typical distress that mainly attributed to increased tire pressure, high temperature and heavy axle loads. Consequently, National Highway Authority (NHA), Pak...

Asphalt fumes are complex mixtures of various organic compounds, including polycyclic aromatic hydrocarbons (PAHs). PAHs require bioactivation by the cytochrome P-450 monooxygenase system to exert toxic/carcinogenic effects. The present study was carried out to characterize the acute pulmonary inflammatory responses and the alterations of pulmonary xenobiotic pathways in rats exposed to asphalt...

Since the 1960s, Stone Mastic Asphalt (SMA) pavement surfaces have been used successfully in Germany on heavily trafficked roads. Because of its excellent performance characteristics, road authorities in Germany as well as major European Countries quickly adopted SMA as a standard wearing course. As a consequence of an asphalt study tour in Europe of an American delegation in 1990, SMA test sec...