Superpave is an acronym for Superior Performing Asphalt Pavements. It is the product of the Strategic Highway Research Program. Superpave includes a new mixture design and analysis system based on performance characteristics of the pavement. It is a multi-faceted system with a tiered approach to designing asphalt mixtures based on desired performance. There is a great deal of work underway to r...

PROBLEM STATEMENT When designing and evaluating asphalt pavements, engineers must have an understanding of how the pavement materials will react to the stresses and strains of vehicle loads at varying temperatures. When a load is applied to asphalt concrete at a certain temperature, to what degree will the pavement "bounce back" to its original height? Pavement designers predict this spring-lik...

This paper investigates the effect of loading level and loading rate on the damage development and strength on the asphalt mixtures tested at three low temperatures. The current AASHTO specification for asphalt mixture low-temperature characterization consists of two tests: the indirect tensile creep (ITC) test and the indirect tensile strength (ITS). In the ITC, the load was applied until the ...

Bio-oil is a dark brown, mobile liquid derived from the thermo-chemical processing of bio-mass. Bio-oils generally contain water and lignin. Lignins are highly-available, well-studied carbohydrate derivative known for their antioxidant properties. For asphalt pavements, oxidation can cause deterioration, a longterm aging process, and eventually result in cracking. Therefore, bio-oil could poten...

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...

A micromechanical finite element (FE) framework was developed to predict the viscoelastic properties (complex modulus and creep stiffness) of the asphalt mixtures. The two-dimensional (2D) microstructure of an asphalt mixture was obtained from the scanned image. In the mixture microstructure, irregular aggregates and sand mastic were divided into different subdomains. The FE mesh was generated ...

Lignin fibers typically influence the mixture performance of stone matrix asphalt (SMA), such as strength, stability, durability, noise level, rutting resistance, fatigue life, and water sensitivity. However, limited studies were conducted to analyze the influence of fibers on the percent voids in mineral aggregate in bituminous mixture (VMA) during the mixture design. This study analyzed the e...

The Statistical Properties of (Asphalt) Mixtures December 2016 Saeed Maghsoodloo and Randy West National Center for Asphalt Technology (NCAT), Auburn University, AL 36849 Abstract In the design of asphalt paving mixtures, aggregates from n stockpiles (generally n = 2, 3, 4, ..., 10) are blended at selected proportions to satisfy specified gradation ranges and other criteria. The mean and varian...

This article outlines the ultrasound data employed to calibrate in the laboratory an analytical model that permits the calculation of the depth of partial-depth surface-initiated cracks on bituminous pavements using this non-destructive technique. This initial calibration is required so that the model provides sufficient precision during practical application. The ultrasonic pulse transit times...

Cold-applied asphalt mixtures are often used for pavement repair, primarily because of the small quantities involved and/or the unavailability of hotmixed asphalt. These cold-applied mixtures have poorer rutting resistance than hot mix asphalt because additives, often solvent, are required to provide adequate workability for them to be placed at ambient temperatures. This study primarily evalua...