Effect of mixing time on reclaimed asphalt mixtures: An investigation by means of imaging techniques. (30th November 2015)

• Record Type: Journal Article
• Authors: Hassan, N.A.; Khan, R.; Raaberg, J.; Lo Presti, D.
• Is Part Of: Construction & building materials. Volume 99(2015)
• Page Start: 54
• Page End: 61
• Publication Date: 2015-11-30
• Subjects: X-ray CT -- Optical Microscopy -- Reclaimed asphalt -- Gyratory compaction; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2015.09.009
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Asphalt mixtures containing reclaimed material were mixed and compacted at five different European laboratories. Same protocols were used but gyratory compactors were from different manufacturers. Imaging techniques were applied to study the mixing of reclaimed material within fresh asphalt mixture. At double mixing time, the asphalt was found well mixed with less variation in the air voids distribution throughout the specimen height. X-ray Computed Tomography (CT) and Optical Microscopy techniques were found useful for microstructural study of reclaimed asphalt mixtures. Abstract: This paper presents an application of imaging techniques to investigate the distribution of reclaimed asphalt and air voids within gyratory compacted specimen. Stone Mastic Asphalt specimens containing reclaimed asphalt, were produced at five different laboratories participating in the collaborative project Re-Road: University of Nottingham, Belgium Road Research Centre, Danish Road Directorate, TU Braunschweig and Laboratoire Centrale de Ponts et Chaussees (now IFSTTAR). This study applies the X-ray Computed Tomography and Optical Microscopy techniques to view the internal structure of the specimen with particular focus on the air voids and reclaimed asphalt distributions within the specimen. The observations revealed that with doubling the mixing time the reclaimed asphalt is well mixed with the fresh materials within the gyratory compacted specimen and also the air voids distribution along the specimen height result to be more consistent.