Modelling short-term aging of asphalt binders using the rolling thin film oven test

2002 ◽  
Vol 29 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Ahmed Shalaby

Simulation of short-term aging of asphalt binders is a widely used procedure in asphalt binder characterization for predicting the binder response to plant mixing and paving under controlled laboratory conditions. There are two laboratory test methods for evaluating the short-term aging of asphalt binders: (i) a method using rotating pans filled with a thin asphalt film termed thin film oven test (TFOT) and (ii) a method using rolling cylindrical asphalt containers termed rolling thin film oven test (RTFOT). In this paper, an attempt is made to develop generalized models for short-term aging effects using the RTFOT aging time as a benchmark. Six binder types representing two PG grades and three source suppliers are conditioned to varying levels of RTFOT aging and tested using the dynamic shear rheometer (DSR). Aging effects are modelled using independent temperature shift models for the shear modulus and phase angle. The paper discusses the sources of errors in producing generalized models and some potential applications of aging models. The research revealed that it is possible to develop and implement such models for unmodified binders.Key words: asphalt, aging, RTFOT, DSR, binder rheology, shear modulus, phase angle.

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ben Liu ◽  
Junan Shen ◽  
Xuyan Song

Aging of an asphalt binder causes the changes in the microstructure and, consequently, in the nanomechanical and rheological properties of the aged asphalt binder. Short-term aging on asphalt binders was simulated using rotating thin film oven (RTFO). These changes in the microstructure and nanomechanical and rheological properties were measured using atomic force microscope (AFM) and dynamic shear rheometer (DSR). The results indicated that (1) the adhesive force of the asphalt binder from AFM tests was increased after RTFO aging; (2)G*of the asphalt binder from DSR tests increased after RTFO aging; (3) the results from AFM were consistent with those from DSR, explaining the mechanism of the changes of rheological properties.


2016 ◽  
Vol 11 (4) ◽  
pp. 302-312 ◽  
Author(s):  
Meor Othman Hamzah ◽  
Seyed Reza Omranian

Many factors affecting pavement performance include variations in binder composition and environmental conditions during asphalt mixture production. Hence, predicting pavement performance is a difficult task. This paper aims to investigate the effects of short term aging on binder viscosity at high temperature. In order to predict the effects of short term aging on the asphalt binder viscosity at high temperatures, a Response Surface Method was performed on the Rotational Viscometer test results. An experimental matrix was planned based on the central composite design for aging duration and test temperature. The test results showed that aging increased the binder viscosity, while increasing test temperature decreased the corresponding value. However, aging effects differ and depend on binder types, test temperatures and aging conditions. It was also found that the Response Surface Method is a fast, effective and reliable method to predict the effects of aging on binder viscosity behaviour at high temperatures.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Jiupeng Zhang ◽  
Guoqiang Liu ◽  
Li Xu ◽  
Jianzhong Pei

Sasobit additives with different dosages were added into 70# and 90# virgin asphalt binders to prepare WMA binders. The rheological properties, includingG∗andδ, were measured by using DSR at the temperature ranging from 46°C to 70°C, and the effects of temperature, additive dosage and aging onG∗/sin⁡δ, critical temperature, and H-T PG were investigated. The results indicate that WMA additive improvesG∗but reducesδ, and the improvement on 70# virgin binder is more significant.G∗/sin⁡δexponentially decreases with the increasing temperature but linearly increases with the increasing additive dosage. Aging effect weakens the interaction between binder and additive but significantly increases the binder’s viscosity; that is whyG∗/sin⁡δis higher after short-term aging. In addition, the critical temperature increases with the increasing additive dosage, and the additive dosage should be more than 3% and 5% to improve H-T PG by one grade for 70# and 90# virgin binder, respectively.


Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4438
Author(s):  
Ingrid Gabrielle do Nascimento Camargo ◽  
Bernhard Hofko ◽  
Johannes Mirwald ◽  
Hinrich Grothe

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.


2020 ◽  
Vol 10 (21) ◽  
pp. 7764
Author(s):  
Ikenna D. Uwanuakwa ◽  
Shaban Ismael Albrka Ali ◽  
Mohd Rosli Mohd Hasan ◽  
Pinar Akpinar ◽  
Ashiru Sani ◽  
...  

The complex shear modulus (G*) and phase angle (δ) are fundamental viscoelastic rheological properties used in the estimation of rutting and fatigue pavement distress in asphalt binder. In the tropical regions, rutting and fatigue cracking are major pavement distress affecting the serviceability of road infrastructure. Laboratory testing of the complex shear modulus and phase angle requires expensive and advanced equipment that is not obtainable in major laboratories within the developing countries of the region, giving rise to the need for an accurate predictive model to support quality pavement design. This research aims at developing a predictive model for the estimation of rutting and fatigue susceptive of asphalt binder at intermediate and high pavement temperatures. Asphalt rheological and ageing test was conducted on eight mixes of modified binders used to build the study database containing 1976 and 1668 data points for rutting and fatigue parameters respectively. The database was divided into training and simulation dataset. The Gaussian process regression (GPR) algorithm was used to predict the rutting and fatigue parameters using unaged and aged conditioned inputs. The proposed GPR was compared with the support vector machine (SVM), recurrent neural networks (RNN) and artificial neural network (ANN) models. Results show that the model performed better in the estimation of rutting parameter than the fatigue parameter. Further, unaged input variables show better reliability in the prediction of fatigue parameter.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6229
Author(s):  
Krzysztof Maciejewski ◽  
Piotr Ramiączek ◽  
Eva Remisova

The presented study explores the effects of decreased temperatures utilized in rolling thin-film oven (RTFOT) laboratory short-term ageing of asphalt binders based on 35/50- and 50/70-penetration paving-grade bitumen. Additionally, the effects of three additives used with these binders at different concentrations are evaluated: liquid anti-stripping agent, liquid warm-mix additive, and solid warm-mix additive. The resulting asphalt binders were subjected to basic (penetration at 25 °C, softening point, dynamic viscosity) and functional high-temperature characterization (G*/sin(δ), high critical temperature, non-recoverable creep compliance). It was found that the decreased short-term ageing temperatures may detrimentally impact the high-temperature grade of bituminous binders, but this effect can be mitigated by the use of appropriate additives. What is more, it was found that bituminous binders may respond differently to the aforementioned factors. Based on the results, it is advised that asphalt binders intended for use in warm-mix asphalts should be thoroughly tested to appropriately simulate the mixture production process and its effects.


Author(s):  
David A. Anderson ◽  
Mihai O. Marasteanu ◽  
James M. Mahoney ◽  
Jack E. Stephens

Two binder technician workshops were held in January 1998, one at the Connecticut Advanced Pavement Laboratory at the University of Connecticut and one at the Northeast Center of Excellence for Paving Technology at Pennsylvania State University. These workshops were followed by a second set in 1999. The overall objective was to improve the repeatability of the test methods used to grade Superpave® asphalt binders. During the workshops, participants demonstrated and discussed the techniques used in their own laboratories. A document, Manual of Practice for Testing Asphalt Binders in Accordance with the Superpave PG Grading System, was developed for use by asphalt binder technicians and as a training aid for a proposed binder technician certification program. The results of the discussions that were held during the workshops and the items that are presented in the manual of practice are summarized. The results were grouped into four main categories: ( a) handling, sampling, and sample preparation; ( b) temperature measurements; ( c) equipment calibration; and ( d) testing procedures. The items discussed here and in the manual of practice supplement and clarify the current AASHTO test methods. The test methods in themselves are not sufficient to ensure uniformity in testing practice from one laboratory to the other.


2017 ◽  
Vol 24 ◽  
pp. 48-54
Author(s):  
Allam Musbah Al Allam ◽  
Mohd Idrus bin Masirin ◽  
Ahmad Suliman B. Ali

This study investigates the effect of oxidation aging on the physical properties of asphalt binder modified by various ratios of soft clay contents. The rheological properties of soft clay modified asphalt binders were performance under unaged and short-term aged, and being applied by using rotational viscometer and dynamic shear rheometer. Therefore, the results indicated that the physical properties of penetration and softening point were consistently reduced and increased, respectively for unaged and short-term aged specimens. The penetration index and viscosity aging index were increased as the soft clay modified binders aged and showed a high significance correlation. It also has the lowest susceptibility for the temperature susceptibility.


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