Composition and Oxidation Dependence of Glass Transition in Epoxy Asphalt

2021 ◽  
pp. 036119812110242
Author(s):  
Panos Apostolidis ◽  
Xueyan Liu ◽  
Sandra Erkens ◽  
Tom Scarpas
Keyword(s):  
Glass Transition ◽  
Composition Dependence ◽  
Asphalt Binder ◽  
Asphalt Binders ◽  
Scanning Calorimetry ◽  
Oxidative Aging ◽  
Epoxy Asphalt ◽  
Ideal Mixing ◽  
Durable Polymer ◽  
Asphalt Materials

Miscibility, and lack of it, is decisive for durable polymer-modified asphalt binders and reflects the long-term performance of asphalt materials in terms of fatigue and thermal cracking. In this work, the glass transition behavior of epoxy asphalt will be assessed extensively after different oxidative aging time periods using differential scanning calorimetry. The composition dependence of glass transition in epoxy asphalt binders over oxidative aging is evaluated by emphasizing the deviation of glass transition temperature ( Tg) with the change in sign and magnitude. An entropy-based analysis of glass transitions in epoxy asphalt is discussed as well. The blends formulated by epoxy and asphalt binder have shown an increase of the Tg deviation from the ideal mixing rule over oxidative aging. Two different shapes of the composition dependence of the Tg values are observed between the blends with and without fillers but showing both distinct positive deviations from the case of mixing ideal materials. The Tg and heat capacity ( Cp) parameters determined in relation to the epoxy asphalt composition provide insights into the effect of limestone fillers on the oxidation-induced embrittlement of epoxy asphalt materials. The results could help select the epoxy proportion in asphalt to develop super-durable and long-lasting pavement materials.

scholarly journals Kinetic Viscoelasticity of Crosslinking Epoxy Asphalt

2019 ◽  
Vol 2673 (3) ◽  
pp. 551-560 ◽  
Author(s):  
Panos Apostolidis ◽  
Xueyan Liu ◽  
Martin van de Ven ◽  
Sandra Erkens ◽  
Tom Scarpas
Keyword(s):  
Mechanical Properties ◽  
Asphalt Binder ◽  
Crosslinking Density ◽  
Asphalt Binders ◽  
Experimental Program ◽  
Model Parameters ◽  
Epoxy Asphalt ◽  
Pavement Structures ◽  
Chemical Hardening ◽  
Modified Binder

Epoxy modification of asphalt binders has been recognized as a very effective technology to alter the chemistry of asphaltic materials in such a way that long-lasting pavement structures can be designed. However, the phenomena that are involved to build up the physico-mechanical properties of epoxy asphalt systems are still unknown. The focus of this paper is on understanding the link between chemistry and the mechanical properties of epoxy asphalt binders during the thermo-irreversible process of chemical hardening. For this purpose, a constitutive model for predicting the evolution of cure-induced stresses in epoxy asphalt binders is proposed, and an experimental program was developed to determine the model parameters. The cure dependency of physico-mechanical parameters of modified binder was obtained and imported into the model to simulate the build-up of material properties during (non-)isothermal hardening of epoxy asphalt binder. The model is implemented in a commercially finite element tool by coupling the chemical, thermal, and mechanical phenomena with multi-physics strategies, and the results are analyzed to identify the influence of different heating conditions on the crosslinking density and subsequently on stress build-up. It was found that the amount of stress build-up during curing was strongly dependent on the heating conditions, and a higher rate of stress build-up was observed at higher applied temperatures. In other words, the processing conditions during in-plant material production or in-field manufacturing of structures made by epoxy asphalt systems affect the material hardening and subsequently the desired functionalities of pavement structures.

scholarly journals Effect of Thermal and Oxidative Aging on Asphalt Binders Rheology and Chemical Composition

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4438
Author(s):  
Ingrid Gabrielle do Nascimento Camargo ◽  
Bernhard Hofko ◽  
Johannes Mirwald ◽  
Hinrich Grothe
Keyword(s):  
Thin Film ◽  
Asphalt Binder ◽  
Chemical Characterization ◽  
Nitrogen Atmosphere ◽  
Asphalt Binders ◽  
Effect Of Temperature ◽  
Ambient Atmosphere ◽  
Test Procedures ◽  
Oxidative Aging ◽  
Aging Test

Aging of asphalt binders is one of the main causes of its hardening, which negatively affects the cracking and fatigue resistance of asphalt binders. Understanding asphalt aging is crucial to improve the durability of asphalt pavements. In this regard, this study aims at understanding and differentiating the effect of temperature and oxygen uptake on the aging mechanisms of unmodified asphalt binders. For that, four laboratory aging procedures were employed. The two standardized procedures, rolling thin-film oven test (RTFOT) and pressure aging vessel (PAV), were considered to simulate the short-term and long-term aging of the asphalt binders, respectively. In addition, two thin-film aging test procedures, the nitrogen atmosphere oven aging test (NAAT) and ambient atmosphere oven aging test (OAAT) were employed to assess the effect of thermal and oxidative aging on unmodified asphalt binder properties. The NAAT procedure is based on the principle that the inert gas minimizes the oxidative aging. The rheological and chemical characterization showed that the high temperatures considered during the NAAT procedure did not change the properties of the unmodified asphalt binders. Therefore, it can be hypothesized that no significant thermal and oxidative aging was observed during NAAT aging procedure for the considered binders and that oxidative aging is the main cause for the hardening.

scholarly journals Flame-Retardant Mechanism of Layered Double Hydroxides in Asphalt Binder

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 801 ◽  
Author(s):  
Kai Zhu ◽  
Yunhe Wang ◽  
Daquan Tang ◽  
Qiang Wang ◽  
Haihang Li ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Layered Double Hydroxides ◽  
Photoelectron Spectroscopy ◽  
Cone Calorimeter ◽  
Asphalt Binder ◽  
Bound Water ◽  
Asphalt Binders ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Double Hydroxides

The flame retardancy of asphalt binders with layered double hydroxides (LDHs) was investigated using limiting oxygen index (LOI) and cone calorimeter tests. The flame-retardant mechanism of the LDHs was also studied with thermogravimetry and differential scanning calorimetry (TG–DSC), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The cone calorimeter testing results indicated that 2 wt.% of the LDHs can decease the peak heat and smoke release rate of asphalt binders. Because a low dose of LDHs can be well dispersed in asphalt binder and favor the formation of polyaromatic structures during combustion, the thermal oxidation resistance and compactness of the char layer can be improved. The LOI of asphalt binder can be increased and the heat and smoke release during combustion can be decreased with 25 wt.% LDHs. The decomposition of LDHs can absorb the heat release of the initial two stages of asphalt combustion and reduce the burning rate of asphalt. Due to the loss of loosely bound water in the LDHs during the blending process and the decrease of dispersibility at a high LDH dose, the improvement of thermal stability is limited.

scholarly journals Optical Characterization of Asphalt Binders Containing Wax Additives

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Mithil Mazumder ◽  
Raju Ahmed ◽  
Moon-Sup Lee ◽  
Soon-Jae Lee
Keyword(s):  
Optical Properties ◽  
Aging Process ◽  
Significant Contribution ◽  
Asphalt Binder ◽  
Optical Characterization ◽  
Crumb Rubber ◽  
Asphalt Binders ◽  
Oxidative Aging ◽  
Modified Binder

In between thermal-oxidative (heat and oxygen) and photo-oxidative (ultraviolet irradiation and oxygen) aging process of bitumen, photo-oxidative aging mainly depends on the optical properties of the asphalt binder. The higher the reflection (or the lower the absorption of the binders), the better the pavement serviceability. The literature review indicates that there is limited research conducted on the optical properties of the binder with wax additives. In this paper, the optical properties of commonly used binders (PG 64-22, Rubber modified binder, and SBS modified binder) containing wax additives (LEADCAP and Sasobit) were investigated using UV-Vis spectrometer. The result of this study showed that (1) the addition of modifiers (crumb rubber and SBS) with the base binder slightly increases the absorption of the binder; (2) the binder types and aging level have significant contribution on optical properties; (3) in general, the aged binders were observed to have higher reflectivity compared to the unaged binders; and (4) the addition of wax additives is observed to have a significant effect on the optical properties.

scholarly journals Characterization of epoxy-asphalt binders by differential scanning calorimetry

2020 ◽  
Vol 249 ◽  
pp. 118800 ◽  
Author(s):  
Panos Apostolidis ◽  
Xueyan Liu ◽  
Sandra Erkens ◽  
Athanasios Scarpas
Keyword(s):  
Differential Scanning Calorimetry ◽  
Asphalt Binders ◽  
Scanning Calorimetry ◽  
Epoxy Asphalt

Impact of Recycled Materials and Recycling Agents on Asphalt Binder Oxidative Aging Predictions

2018 ◽  
Vol 2672 (28) ◽  
pp. 277-289 ◽  
Author(s):  
Sara Pournoman ◽  
Elie Y. Hajj ◽  
Nathan Morian ◽  
Amy Epps Martin
Keyword(s):  
Asphalt Binder ◽  
Asphalt Binders ◽  
Complex Nature ◽  
Recycled Asphalt ◽  
Recycled Materials ◽  
Reclaimed Asphalt ◽  
Oxidative Aging ◽  
Cracking Potential ◽  
Binder Oxidation ◽  
The Individual

The overall objective of this study was to evaluate the influence of selected recycling agents (RAs) and recycled materials on the development of cracking potential with respect to oxidative aging. Given the complex nature of varying base asphalt binders, recycled materials, whether recycled asphalt pavement (RAP), reclaimed asphalt shingles (RAS), or both, and the complexity of their combined interactions with recycling agents, standard evaluation protocols for binder grading and evaluation may be insufficient. The binder blend aging predictions or oxidation modeling evaluation was introduced as a means to evaluate the combined influence of both binder oxidation kinetics and resulting rheological changes on the measured cracking potential of the various binder blends—that is, Glover–Rowe (G-R) parameter—driven by temperature estimation modeling over simulated in-service durations at example geographic locations. This evaluation has demonstrated the importance of adequate characterization of the specific materials being used in conjunction with selection of the correct dose of the appropriate recycling agent to ensure sufficient resistance to cracking and embrittlement of proposed material combinations. The combined influence of all the interested components did not always add up to the sum of the individual parts, nor are the measured interactions consistent with increased levels of oxidation. Therefore, the prevailing conclusion of the study as a whole indicated that material-specific evaluations are needed to identify the complex interactions taking place within the material combinations of interest, but also multiple levels of aging at appropriate intervals may be necessary for comprehensive characterization.

scholarly journals Application of Acoustic Emissions Technique in Assessment of Cracking Performance of Asphalt Pavement Materials

2021 ◽  
Author(s):  
Behzad Behnia
Keyword(s):  
Low Temperature ◽  
Acoustic Emissions ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Oxidative Aging ◽  
Aged Asphalt ◽  
Asphalt Materials ◽  
Cracking Performance ◽  
Low Temperature Cracking ◽  
Viable Approach

This chapter focuses on various applications of acoustic emissions (AE) technique in evaluation of cracking in asphalt pavements including (1) assessment of low-temperature cracking of asphalt binders and mixtures and (2) quantitative characterization of rejuvenators’ efficiency in restoring aged asphalt pavements to their crack-resistant state. The AE-based embrittlement temperature results of 24 different asphalt materials consisting of eight different binders, each at three oxidative aging levels are presented. Results show that embrittlement temperatures correlated well with corresponding bending beam rheometer (BBR-based) critical cracking temperatures with R2 = 0.85. This chapter also presents application of AE for evaluation of rejuvenators’ efficiency on asphalt materials at various oxidative aging levels. The Geiger’s iterative source location method was employed to accurately determine embrittlement temperatures throughout the thickness of rejuvenator-treated asphalt samples. Results showed that the low temperature cracking properties of oxidative aged materials after 2 weeks of dwell time of rejuvenator have been recuperated. Moreover, it was observed that cracking characteristics of aged asphalt 6–8 weeks after applying rejuvenator far exceeded that of the virgin materials. The promising results suggest that the AE technique can be considered as a viable approach for the assessment of low temperature behavior of asphalt pavements.

scholarly journals PEG-POSS Star Molecules Blended in Polyurethane with Flexible Hard Segments: Morphology and Dynamics

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 99
Author(s):  
Konstantinos N. Raftopoulos ◽  
Edyta Hebda ◽  
Anna Grzybowska ◽  
Panagiotis A. Klonos ◽  
Apostolos Kyritsis ◽  
...  
Keyword(s):  
Glass Transition ◽  
Star Polymer ◽  
Polymerization Process ◽  
Degree Of Crystallinity ◽  
Dielectric Relaxation Spectroscopy ◽  
Scanning Calorimetry ◽  
Similar System ◽  
Soft Phase ◽  
Hard Segments ◽  
Star Molecules

A star polymer with a polyhedral oligomeric silsesquioxanne (POSS) core and poly(ethylene glycol) (PEG) vertex groups is incorporated in a polyurethane with flexible hard segments in-situ during the polymerization process. The blends are studied in terms of morphology, molecular dynamics, and charge mobility. The methods utilized for this purpose are scanning electron and atomic force microscopies (SEM, AFM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and to a larger extent dielectric relaxation spectroscopy (DRS). It is found that POSS reduces the degree of crystallinity of the hard segments. Contrary to what was observed in a similar system with POSS pendent along the main chain, soft phase calorimetric glass transition temperature drops as a result of plasticization, and homogenization of the soft phase by the star molecules. The dynamic glass transition though, remains practically unaffected, and a hypothesis is formed to resolve the discrepancy, based on the assumption of different thermal and dielectric responses of slow and fast modes of the system. A relaxation α′, slower than the bulky segmental α and common in polyurethanes, appears here too. A detailed analysis of dielectric spectra provides some evidence that this relaxation has cooperative character. An additional relaxation g, which is not commonly observed, accompanies the Maxwell Wagner Sillars interfacial polarization process, and has dynamics similar to it. POSS is found to introduce conductivity and possibly alter its mechanism. The study points out that different architectures of incorporation of POSS in polyurethane affect its physical properties by different mechanisms.

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