Innovative Materials, New Design Methods, and Advanced Characterization Techniques for Sustainable Asphalt Pavements

Abstract

New and innovative materials are continually being researched and developed by asphalt technologists, particularly in the last decade to find the most economical, efficient, and environmentally friendly product to use on roads. Parallel to that, advanced characterization techniques and methodologies are also being developed to characterize materials for best results. Innovative materials include recycled and waste materials (green materials), low-cost and high-performance materials, and materials that reduce energy consumption. Recycled asphalt pavement (RAP) material is considered among the most common materials used in asphalt pavements. e RAP material is a useful alternative to virgin materials because it reduces the need to use virgin aggregate which has limited resources in some areas of the United States and the World [1]. e FHWA continues to encourage the use of waste tire rubber for asphalt paving for its cost-effectiveness, easy handling, and better fatigue performance [2]. Plastic waste is relatively a new material recently introduced in the asphalt technology [4]. Another innovative material is the bioasphalt that is considered a breakthrough in renewable pavements. e bioasphalt is produced from non-petroleum-based renewable resources such as corn, rice, potato starches, and other plants, which are converted into a type of bitumen binder for the asphalt [3]. In this special issue, published papers are dealing with innovative materials, design methods, and characterization techniques that well agree with the main scope and goals of the special issue. e papers are mainly classified into three main categories: (1) new materials and their behavior and performance, (2) the mechanics and performance of composite paving materials, and (3) new design and characterization methods and modeling.A study by W. S. Brito et al. assessed the reuse of fly ash of Bayer process boilers in geopolymer synthesis. X-ray fluorescence (XRF) and scanning electron microscopy (SEM) techniques were used to characterize the raw materials and geopolymers. e study concluded that synthesized geopolymers have great potential for production of geopolymeric materials with greater mechanical compressive strength. C. Kai et al. utilized silica powder in styrenebutadiene-styrene-(SBS-) modified asphalt. e silica powder was collected from the exhaust gases produced by smelting industrial silicon often used as a cement concrete admixture in China. Rheological tests such as viscosity, dynamic shear rheometer (DSR), and bending beam rheometer (BBR) tests were used to study the behavior of the composite-modified asphalt. e results of the study showed that the high-temperature and low-temperature performances were improved by the increase in silica powder content and ratio of filler-asphalt, and by the increase in the silica powder content with an optimum value of 7%, respectively. However, the increase in the ratio of filler-asphalt reduced the low-temperature cracking resistance of the asphalt. A study by M. Irfan et al. investigated the effect...

An assessment of the strategies for the energy-critical elements necessary for the development of sustainable energy sources

“…a Stiffness modulus. b Maximum flexural stress and strain at failure (Al-Khateeb et al 2019 ; Wang et al 2021 ) …”