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Sonja Pape

Bio: Sonja Pape is an academic researcher from North Carolina State University. The author has contributed to research in topics: Asphalt & Dynamic modulus. The author has an hindex of 5, co-authored 7 publications receiving 50 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors introduced energy dispersive X-ray spectroscopy (EDS) scanning electron microscopy (SEM) as a means to analyze the degree of blending between RAP and fresh materials in asphalt concrete.
Abstract: A major impediment to the widespread use of asphalt concrete with a high content of reclaimed asphalt pavement (RAP) is uncertainty in the degree of blending between the RAP and the fresh binder. Furthering knowledge concerning the blending between RAP and fresh binder has been difficult because of the lack of an experimental method to quantify the degree of blending in asphalt concrete. This study introduces energy dispersive X-ray spectroscopy (EDS) scanning electron microscopy (SEM) as a means to analyze the degree of blending between RAP and fresh materials in asphalt concrete. EDS allows for mapping the distribution and relative proportion of elements in a sample, hence, allowing for the detection of the distribution of elements in an asphalt concrete specimen. Fresh and RAP binders will have a similar elemental composition. Therefore, titanium dioxide in a fine powder form (0.15-µm particles) is blended with the fresh binder as a tracer before the production of asphalt concrete to enable delineation...

30 citations

Journal ArticleDOI
TL;DR: In this paper, small specimens were evaluated for dynamic modulus and simplified viscoelastic continuum damage fatigue in asphalt mixture performance testing to enable the testing of as-built pavement layers.
Abstract: The use of small specimen geometries in asphalt mixture performance testing to enable the testing of as-built pavement layers has been gaining attention in recent years. Small specimens could also improve the testing efficiency of laboratory-fabricated specimens by allowing the extraction of multiple test specimens per gyratory-compacted sample. Rigorous assessment of the small specimen geometries is required before the use of such geometries is standardized. In this study, small specimens were evaluated for dynamic modulus and simplified viscoelastic continuum damage fatigue. Three specimen geometries (100-mm- and 38-mm-diameter cylindrical specimens and 25- × 50-mm prismatic specimens) were compared by using five mixtures with a nominal maximum aggregate size (NMAS) ranging from 9.5 to 25.0 mm. The results show that the dynamic modulus and phase angle master curves agreed at low and intermediate temperatures, regardless of the NMAS values of the mixture. At the high temperature, the small specimen dynam...

20 citations

01 Jan 2017
TL;DR: In this article, small specimens were evaluated for dynamic modulus and simplified viscoelastic continuum damage fatigue in asphalt mixture performance testing to enable the testing of as-built pavement layers.
Abstract: The use of small specimen geometries in asphalt mixture performance testing to enable the testing of as-built pavement layers has been gaining attention in recent years. Small specimens could also improve the testing efficiency of laboratory-fabricated specimens by allowing the extraction of multiple test specimens per gyratory-compacted sample. Rigorous assessment of the small specimen geometries is required before the use of such geometries is standardized. In this study, small specimens were evaluated for dynamic modulus and simplified viscoelastic continuum damage fatigue. Three specimen geometries (100-mm- and 38-mm-diameter cylindrical specimens and 25- × 50-mm prismatic specimens) were compared by using five mixtures with a nominal maximum aggregate size (NMAS) ranging from 9.5 to 25.0 mm. The results show that the dynamic modulus and phase angle master curves agreed at low and intermediate temperatures, regardless of the NMAS values of the mixture. At the high temperature, the small specimen dynam...

14 citations

Journal ArticleDOI
TL;DR: The use of 38mm-diameter small specimens for uniaxial dynamic modulus and cyclic fatigue asphalt mixture performance testing offers a significant opportunity to improve the efficiency of laborator as mentioned in this paper.
Abstract: The use of 38-mm-diameter small specimens for uniaxial dynamic modulus and cyclic fatigue asphalt mixture performance testing offers a significant opportunity to improve the efficiency of laborator...

11 citations

Journal ArticleDOI
TL;DR: In this article, a tracer-based energy dispersive X-ray spectroscopy (EDS) analysis of asphalt mixtures is presented to evaluate the ability to form a stable blend between the tracer and virgin asphalt binder.
Abstract: Several past studies have demonstrated merit to using tracer-based energy dispersive X-ray spectroscopy (EDS) analysis to investigate blending between virgin and recycled materials in asphalt mixtures. However, these past studies have focused on proof of concept and did not establish robust fabrication and microscopy procedures. This study rigorously evaluates the ability to form a stable blend between the tracer and virgin asphalt binder, and the potential for tracer smearing during the preparation of EDS specimens. The results demonstrate that a high shear mixer can be used to prepare homogeneous, stable blends of a titanium dioxide tracer and virgin binder. A critical evaluation of an asphalt mixture specimen prepared to contain specific areas with and without the tracer demonstrates no evidence of tracer smearing due to sample preparation. The results demonstrate that tracer-based EDS analysis of asphalt mixtures can measure local recycled material availability. This article is protected by copyright. All rights reserved.

8 citations


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Journal ArticleDOI
TL;DR: In this article, the authors reviewed techniques and analyses performed on microstructure of the asphalt binder and mixture using Scanning Electron Microscopy (SEM) and ESEM.

116 citations

Journal ArticleDOI
TL;DR: In this article, the results of laboratory testing indicated that the morphology of SBS modified binders was influenced by storage temperature and polymer content, which was attributed to increased modulus and enhanced critical strain energy release rate of polymer-modified asphalt mixtures.

50 citations

Journal ArticleDOI
TL;DR: It is common practice to assume full blending of the aged binder of reclaimed asphalt (RA) within the design of new asphalt mixtures as discussed by the authors, but this assumption has often led designe...
Abstract: It is common practice to assume full blending of the aged binder of reclaimed asphalt (RA) within the design of new asphalt mixtures. Although being practical, this assumption has often led designe...

47 citations

Journal ArticleDOI
Chamod Hettiarachchi1, Xiangdao Hou1, Qian Xiang1, Dara Yong1, Feipeng Xiao1 
TL;DR: In this paper, Fourier Transform Infrared Spectroscopy (FTIR) analysis of the extracted asphalt pavement binder from mixtures was used to determine the degree of blending with regard to blending duration and blending temperature.
Abstract: The degree of blending of reclaimed asphalt pavement (RAP) binder is profoundly influencing the performance of asphalt mixtures containing RAP. Hence, it is essential to know the amount of RAP binder mobilized into the mixture to produce more durable asphalt mixtures. However, understanding the factors affecting the degree of blending and quantifying the degree of blending is still an open problem for researchers. This study investigates the effect of several factors such as blending method, blending temperature, blending duration, and RAP content on the degree of blending using Fourier Transform Infrared Spectroscopy (FTIR) analysis of the extracted binder from mixtures. It is revealed that the blending method, blending temperature, and blending duration have a significant influence on the degree of blending. The study revealed that prolonged blending durations and elevated mixing temperatures could improve the degree of blending. The amount of RAP in the mixture has little or no influence on the degree of blending. Further, based on the results, a blending chart is developed to determine the degree of blending with regard to blending duration and blending temperature.

37 citations

Journal ArticleDOI
TL;DR: In this article, the use of recycled materials in bituminous mixtures for road infrastructures has been discussed, with a focus on the reduction of the environmental burdens related to highway infrastructure.
Abstract: Recently, the reduction of the environmental burdens related to highway infrastructures has been in the spotlight. Within this context, the use of recycled materials in bituminous mixtures for road...

35 citations