2013 Session: 743

• Evaluation of Effect of Recycled Roof Membrane on Asphalt Mixture Performance Properties
  Abstract: ABSTRACTThis paper examines the effect of replacing part of the virgin binder with recycled roof membrane on the performance of hot mix asphalt mixtures with high percentages of recycled asphalt (RAP). The use of recycled roof membranes influences the asphalt mixture properties. In this study the influence of replacement of virgin binder by the binder in recycled roof membranes (GRM-50) on the performance properties of surface and base course asphalt mixtures with high RAP contents evaluated. Functional mixture properties like stiffness, fatigue and permanent deformation were determined to evaluate the performance. In addition to mixture properties also the properties of the recovered binders of these mixtures were determined. Both empirical and fundamental binder properties of the recovered binders were determined using penetration, ring and ball, and Dynamic Shear Rheometer (DSR) tests. The DSR results show that the recovered binder from mixtures containing recycled roof membrane (GRM-50) has significantly higher complex shear modulus G* values especially at high temperature (low frequency). They also show a lower phase angle d over a wide range of frequency and temperature compared to recovered binders from mixtures with only RAP. In line with the binder test results, the mixture tests clearly show that replacement of part of the virgin bitumen in the RAP mixture with recycled roof membrane increases the mixture dynamic stiffness, fatigue life and resistance to permanent deformation. With the Hirsch model it was verified if sufficient binder blending exists in the mixture, which is important in regard to durability.
  Authors: Merine, Girum Mengiste; Hagos, Eyassu Tesfamariam; van de Ven, Martin F. C.
  Authors: Merine, Girum Mengiste; Hagos, Eyassu Tesfamariam; van de Ven, Martin F. C.
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 743
  Paper Number: 13-2095
• Influence of BituTech RAP Bioasphalt on Viscoelastic Properties of Reclaimed Asphalt Mixtures
  Abstract: The inclusion of reclaimed asphalt pavement (RAP) into asphalt paving mixtures had become more popular over the last five plus years due to the rising cost of oil, limited amount of quality virgin materials, and limited space in landfills. However, incorporating RAP into a mixture at a high rate exposes some challenges from the design perspective, especially when it comes to the influence of the stiff RAP binder on the properties of the asphalt mixture. A virgin asphalt binder softer than the conventional binder typically used for a particular project or a recycling agent are sometimes used to soften or rejuvenate the stiff, oxidized RAP binder. This paper summarizes the laboratory evaluation of one such bio-rejuvenating agent called BituTech RAP. The impact of BituTech RAP on the viscoelastic properties of high RAP content mixtures from Manitoba, Canada were evaluated for any possible moisture damage or thermal cracking problems that may arise from the use of RAP in such wet-freeze environment. Mixtures containing 15 and 50% RAP, with and without BituTech RAP, were tested using the dynamic modulus (E*) at multiple freeze-thaw cycles and the thermal stress restrained specimen test. The modified Huet-Sayegh, 2S2P1D, model was used to generate the E* complex modulus and to assess the change in loss and storage modulus resulting from the addition of the rejuvenating agent. The Cole-Cole plots showed an increase in the loss modulus for mixtures with BituTech RAP. Furthermore, an improved resistance to moisture damage was observed with the use of BituTech RAP as demonstrated with an increase in the storage and loss modulus ratios. The addition of BituTech RAP also restored the thermal cracking properties of the asphalt mixtures such as the thermal relaxation modulus, glassy transition temperature, and fracture temperature. A preliminary cost analysis was also conducted and potential cost savings were observed using BituTech RAP promoting the use of higher percentages of RAP without affecting the overall performance of the mixture.
  Authors: Hajj, Elie Y; Souliman, Mena I.; Alavi, Mohammad Zia; Loria-Salazar, Luis
  Authors: Hajj, Elie Y; Souliman, Mena I.; Alavi, Mohammad Zia; Loria-Salazar, Luis
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 743
  Paper Number: 13-2253
• Evaluation of Environmental Susceptibility of Bituminous Mastic Viscosity as a Function of Mineral and Biomass Fillers
  Abstract: In addition to allowing for the load transfer in the aggregate skeleton, bituminous mastics influence many of the other important asphalt mixture properties, such as the overall stability of the mixture, air void distribution, bitumen drain-down during transport, its workability during the laying process and the overall in-time performance of the pavement. To understand the properties of asphalt mixtures and its resistance against environmentally induced failure mechanisms, it is of paramount important to not only study bitumen and the asphalt mixture, but also the mastic itself. Current asphalt design procedures do not take the mastic behavior into account which is an important flaw in our current ability to design and predict asphalt concrete response. In this paper, results of an ongoing research project are given which focuses on enhancing the understanding of the mastic phase as well as develop a new test protocol to characterize mastics. A description is given of the measurements of mastic viscosity for different types of mastics in which the bitumen source is kept as a constant, but with varying fillers as well as concentrations. The environmentally susceptibility was hereby also investigated by conditioning the samples to ageing and moisture conditioning. In addition to some of the traditional fillers, biomass fillers were also included in some of the mastics to show their impact on the viscosity under varying conditions. Results showed, the developed test protocol was able to clearly identity filler properties on the mastic viscosity. Furthermore, a critical filler concentration was identified beyond which the viscosity behaviour becomes non-linear. It is also showed that the moisture and aging have significant effect on the viscosity of mastics.
  Authors: Hesami, Ebrahim; Bidewell, Nathan; Birgisson, Bjorn; Kringos, Niki
  Authors: Hesami, Ebrahim; Bidewell, Nathan; Birgisson, Bjorn; Kringos, Niki
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 743
  Paper Number: 13-2501
• Influence of Cecabase on Mechanistic, Economical, and Environmental Attributes of Polymer-Modified Asphalt Mixture
  Abstract: In the last decades, extensive amount of experimental laboratory and field studies were conducted with different warm mix asphalt (WMA) technologies around the world. While good performance for the WMA mixtures has been reported, their use with polymer-modified asphalt binders is still creating a concern for some highway agencies. This paper summarizes the laboratory evaluation of one of those WMA products called Cecabase™ RT with a typical dense-graded polymer-modified asphalt mixture used in California and Nevada. The objective of this paper was to assess whether Cecabase™ RT negatively influence the outstanding performance and durability experienced by the state DOTs for the polymer-modified asphalt mixture. The WMA mixture was produced in the laboratory and compared to an HMA control mixture using identical aggregates, binder and mix design. Overall, the presented results indicated that the use of the Cecabase™ RT warm-mix additive at lower production and compaction temperatures resulted in a similar or better resistance to moisture damage, rutting, and fatigue cracking when compared to the conventional HMA. Preliminary calculations showed potential fuel savings associated with the use of Cecabase™ RT. In addition, measurable energy savings and significant reduction in CO2 emissions are anticipated with the use of Cecabase™ RT additive compared to the conventional HMA.
  Authors: Hajj, Elie Y; Souliman, Mena I.; Cortez, Edward; Jorda, Eric
  Authors: Hajj, Elie Y; Souliman, Mena I.; Cortez, Edward; Jorda, Eric
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 743
  Paper Number: 13-3133
• Evaluation of Environmental Susceptibility of Bituminous Mastic Viscosity as a Function of Mineral and Biomass Fillers
  Authors: Hesami, Ebrahim
  Authors: Hesami, Ebrahim
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 743
  Paper Number: 13-2501
• Influence of BituTech RAP Bioasphalt on Viscoelastic Properties of Reclaimed Asphalt Mixtures
  Authors: Hajj, Elie
  Authors: Hajj, Elie
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 743
  Paper Number: 13-2253
• Influence of Cecabase on Mechanistic, Economical, and Environmental Attributes of Polymer-Modified Asphalt Mixture
  Authors: Hajj, Elie
  Authors: Hajj, Elie
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 743
  Paper Number: 13-3133