| 1. |
- Ahmed, Abubeker W., et al.
(author)
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An Algorithm to Estimate Rational Values of Phase Angles and Moduli of Asphalt Mixtures
- 2013
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In: International Journal of Pavement Research and Technology. - Taiwan : Chinese Society of Pavement Engineering. - 1996-6814 .- 1997-1400. ; 6:6, s. 745-754
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Journal article (peer-reviewed)abstract
- The objective of this study was to develop and evaluate an algorithm based on Fast Fourier Transform (FFT) that can calculate rational values of phase angle (f) and moduli of the variants of asphalt mixtures for the data obtained from the different frequency sweep tests. f and moduli for ten different asphalt mixtures resulting in over 690 data points collected from both USA and Sweden were computed using FFT. Theoretical observations revealed that there were significant differences for f between FFT and other methods to the order of 10-50%; however, there was no difference in moduli estimates for any mix and was independent of the test. Precisely, the FFT method produced rational f for mixtures that deviate from conventional mixture properties. Furthermore, statistical comparisons corroborated the predicted f estimates indicative of significant differences between the analysis techniques; but, the moduli were unaffected by the analysis methods. The study successfully illustrated the FFT technique, a user-friendly analytical procedure that can obviate the errors in the rational estimation of the acutely sensitive viscoelastic parameters.
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| 2. |
- Butt, Ali Azhar, 1984-, et al.
(author)
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The Effect of Wax Modification on the Performance of Mastic Asphalt
- 2010
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In: International Journal of Pavement Research and Technology (IJPRT). - No.300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan : Chinese Society of Pavement Engineering. - 1997-1400. ; 3:2, s. 86-95
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Journal article (peer-reviewed)abstract
- The scope of this study is to evaluate the mechanical performance of the polymer modified mastic asphalt with 4% montan wax (Asphaltan A) additive. The impact of wax modification on binder, binder/filler mixtures and mastic asphalt was investigated in the laboratory. Wax modified binder properties were determined using dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) spectroscopy and conventional tests (softening point, penetration, elastic recovery, breaking point, viscosity and storage stability). The bending beam rheometer (BBR) was used for determining low temperature creep compliance and the tensile stress restrained specimen test (TSRST) for determining low temperature fracture. The fatigue cracking behavior of mastic asphalt was investigated using Superpave Indirect Tensile Test (IDT). Based on HMA Fracture Mechanics the influence of wax on the asphalt mixture resistance to fatigue and brittle cracking has been evaluated. The addition of wax to the polymer modified binder resulted in a viscosity reduction at higher temperatures, indicating a possible lower production and laying temperature as compared to asphalt without wax additive. DMA and BBR results showed some increase in stiffness and a more elastic response of the wax modified binder at medium and low temperatures. The TSRST fracture temperature was higher for the mastic asphalt containing wax, indicating a certain negative impact of wax modification.
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| 3. |
- Cafiso, S., et al.
(author)
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Distress and profile data analysis for condition assessment in pavement management systems
- 2019
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In: International Journal of Pavement Research and Technology. - : Springer Science and Business Media LLC. - 1996-6814 .- 1997-1400. ; 12:5, s. 527-536
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Journal article (peer-reviewed)abstract
- Pavement data collection is the most expensive and time consuming component of Pavement Management System (PMS). Thus, possible methods of minimizing the need of such data might be critical in reducing pavement condition monitoring costs. Also the ability to relate pavement performance prediction models (frequently roughness based) to hot mix asphalt field performance models (distress based) provides valuable conclusions and input in pavement design, performance assessment, maintenance and rehabilitation strategies. Objective of this study was to examine whether specific distresses can influence roadway profile so as to be able to relate the two. The influence of pavement distresses on road profile has been investigated over the years. However, past studies provided conflicting conclusions. Thus, in this study an alternative approach was considered due to the availability of high quality and detailed distress data collected with the Laser Crack Measurement System (LCMS) of the Automatic Road Analyzer, ARAN. As it was expected, specific distresses have higher impact in longitudinal roughness since they are present on the roadway surface at regular intervals (i.e., specific frequencies). For this reason, instead of using summary indexes (i.e., International Roughness Index (IRI), Pavement Condition Index (PCI)), the Power Spectral Density (PSD) of the roadway profile at specific frequency bandwidths was considered along with distresses. The analysis indicated that a specific subset of distresses is affecting roughness at definite wavelength frequencies. Alligator cracking and rutting standard deviation provided the best correlation. IRI was correlated better with distress (e.g. rutting standard deviation) at lower profile frequencies. At high frequency domain (i.e., below 0.8 m wavelengths) better correlation between IRI and high severity cracking was observed through the PSD. Considering multiple frequencies in the regression models between roughness and distresses, the goodness of fit has not necessarily improved. However, the role of different bandwidths was evident. In addition to the specific results, the methodology presented in this study can be used elsewhere to assess potential relations between pavement roughness and distress components.
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| 4. |
- Lu, Xiaohu, et al.
(author)
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Performance Evaluation of Polymer Modified Bitumens on a Heavily Trafficked Test Road
- 2014
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In: International Journal of Pavement Research and Technology. - : Chinese Society of Pavement Engineering. - 1997-1400. ; 7:6, s. 381-388
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Journal article (peer-reviewed)abstract
- In asphalt paving, polymer modified bitumens (PMBs) have more potential for use and can clearly demonstrate the value of their initial higher cost. To further assess the sustainable benefits of using PMBs, a test road was constructed on a highway in Sweden. In this paper, the asphalt binders used were investigated extensively using rheological and chemical methods, and asphalt field cores characterized with respect to permanent deformation and fatigue. It was found that the modified binders, particularly with SBS polymers, retain better rheological properties in comparison with conventional ones, even after several years in the field; these include higher strain recovery and lower non-recoverable compliance at high temperatures, and lower stiffness at low temperatures. The SBS modified binders also demonstrate good aging resistance, shown by both laboratory aging tests and field aging. the high resistance to aging for the SBS modified binders was also evident in the stiffness measurement made on asphalt field cores. Moreover, the modified binders with SBS polymers significantly enhance fatigue behaviour.
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