scholarly journals Aging of Rejuvenated Asphalt Binders

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Mojtaba Mohammadafzali ◽  
Hesham Ali ◽  
James A. Musselman ◽  
Gregory A. Sholar ◽  
Wayne A. Rilko
Keyword(s):  
High Temperature ◽  
Great Influence ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Accelerate Aging ◽  
Aging Rate ◽  
Important Concern ◽  
Different Types ◽  
Aged Binder

An important concern that limits the RAP content in asphalt mixtures is the fact that the aged binder that is present in the RAP can cause premature cracking. Rejuvenators are frequently added to high RAP mixtures to enhance the properties of the binder. There is no existing method to predict the longevity of a rejuvenated asphalt. This study investigated the aging of rejuvenated binders and compared their durability with that of virgin asphalt. Various samples with different types and proportions of RAP, virgin binder, and rejuvenator were aged by RTFO and three cycles of PAV. DSR and BBR tests were conducted to examine the high-temperature and low-temperature rheological properties of binders. Results indicated that the type and dosage of the rejuvenator have a great influence on the aging rate and durability of the binder. Some rejuvenators make the binder age slower, while others accelerate aging. These observations confirm the importance of evaluating the long-term aging of recycled binders. For this purpose, critical PAV time was proposed as a measure of binder’s longevity.

Long-Term Field Aging of Warm-Mix and Hot-Mix Asphalt Binders

2017 ◽  
Vol 2632 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Weiguang Zhang ◽  
Shihui Shen ◽  
Shenghua Wu ◽  
Louay N. Mohammad
Keyword(s):  
High Temperature ◽  
Prediction Model ◽  
Hot Mix Asphalt ◽  
Field Studies ◽  
Asphalt Binders ◽  
Climate Effect ◽  
Air Voids ◽  
Multiple Parameters ◽  
Term Field

Limited field studies have considered the aging of warm-mix asphalt (WMA) binders, especially from the perspective of long-term aging. This paper quantifies the long-term (10 to 82 months) field aging properties of WMA binders and the control hot-mix asphalt (HMA) binders and identifies the key factors associated with long-term field aging of asphalt. Asphalt binders from 23 field projects consisting of 65 HMA and WMA pavements were recovered, and high-temperature performance grade (PG) was tested. The effects of climate, month of aging, WMA technologies, and original binder high-temperature PG on field asphalt aging were analyzed. A prediction model that included multiple parameters was developed and validated. Results indicated that Evotherm WMA binder had a lower high-temperature PG than HMA binder shortly after construction, but this difference reduced with time. No statistical difference of field aging between HMA and WMA binders was observed. The climate effect on asphalt field aging was apparent within dry areas or freeze areas, whereas the aging difference between dry and freeze areas was inconclusive and requires further research. Other conclusions were that ( a) the field asphalt aging affects more of top-down longitudinal wheelpath crack than transverse crack, ( b) foaming WMA binder ages slowest of all binders considered, ( c) PG 64-XX and PG 70-XX binders aged more than PG 58-XX and PG 76-XX binders, and ( d) the prediction model had good agreement with test results and was well validated. The identified factors that affected field asphalt aging were overlay thickness, in-place air voids, effective binder content, complex shear modulus, and solar radiation.

scholarly journals High-Temperature Performance of Asphalt Mixtures: Preliminary Analysis for the Standard Technical Index Based on Gray Relational Analysis Method

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jian Xu ◽  
Yan Gong ◽  
Li-Biao Chen ◽  
Tao Ma ◽  
Jun-Cheng Zeng ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
High Temperature ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Gray Relational Analysis ◽  
Low Grade ◽  
Modified Asphalt ◽  
Relational Analysis ◽  
Temperature Performance

Aiming to evaluate the high-temperature performance of asphalt binders and asphalt mixtures and to investigate the reliability of the standard technical indexes to evaluate the performance of the asphalt, six typically used asphalt types were employed in this study. The standard high-temperature rheological test, the multiple stress creep recovery (MSCR) test, and the zero-shear viscosity (ZSV) test were employed to characterize the high-temperature performance and non-Newtonian fluid properties of the asphalt. Meanwhile, the high-temperature performance of the asphalt mixture was evaluated through the rutting tests based on the mixture design of AC-13. In general, the modified asphalt performed better than the unmodified asphalt according to the high-temperature rheological properties tests. The ranking of the six kinds of asphalt was confirmed to be different in various laboratory tests. The test results of the asphalt binders showed that the Tafpack Super- (TPS-) modified asphalt performed best in the MSCR and ZSV tests, while the low-grade asphalt PEN20 had the best technical indexes in the dynamic shear rheometer (DSR) test. Besides, the relation between the asphalt and the asphalt mixture was analyzed by gray relational analysis (GRA) method. The present rutting indicator G ∗ / sin   δ  and  G ∗ / 1 − sin   δ ⋅   tan   δ − 1 for evaluating the asphalt mixtures’ high-temperature performance might no longer be suitable. The Cross/Williamson model was the most suitable for calculating and fitting the ZSV, which could be used as the key indicator of the high-temperature performance evaluation of the asphalt. This work lays a foundation for the further study of the high-temperature performance evaluation of asphalt binders.

scholarly journals The Effect of Aging on the Cracking Resistance of Recycled Asphalt

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Mojtaba Mohammadafzali ◽  
Hesham Ali ◽  
James A. Musselman ◽  
Gregory A. Sholar ◽  
Aidin Massahi
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Fatigue Cracking ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Reclaimed Asphalt Pavement ◽  
Cracking Resistance ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt ◽  
Important Concern

Fatigue cracking is an important concern when a high percentage of Reclaimed Asphalt Pavement (RAP) is used in an asphalt mixture. The aging of the asphalt binder reduces its ductility and makes the pavement more susceptible to cracking. Rejuvenators are often added to high-RAP mixtures to enhance their performance. The aging of a rejuvenated binder is different from virgin asphalt. Therefore, the effect of aging on a recycled asphalt mixture can be different from its effect on a new one. This study evaluated the cracking resistance of 100% recycled asphalt binders and mixtures and investigated the effect of aging on this performance parameter. The cracking resistance of the binder samples was tested by a Bending Beam Rheometer. An accelerated pavement weathering system was used to age the asphalt mixtures and their cracking resistance was evaluated by the Texas Overlay Test. The results from binder and mixture tests mutually indicated that rejuvenated asphalt has a significantly better cracking resistance than virgin asphalt. Rejuvenated mixtures generally aged more rapidly, and the rate of aging was different for different rejuvenators.

scholarly journals The Effect of Morphological Characteristic of Coarse Aggregates Measured with Fractal Dimension on Asphalt Mixture’s High-Temperature Performance

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hainian Wang ◽  
Yin Bu ◽  
Yanzhe Wang ◽  
Xu Yang ◽  
Zhanping You
Keyword(s):  
Fractal Dimension ◽  
High Temperature ◽  
Los Angeles ◽  
Coarse Aggregate ◽  
Asphalt Mixture ◽  
Great Influence ◽  
Asphalt Mixtures ◽  
Morphological Properties ◽  
Coarse Aggregates ◽  
Temperature Performance

The morphological properties of coarse aggregates, such as shape, angularity, and surface texture, have a great influence on the mechanical performance of asphalt mixtures. This study aims to investigate the effect of coarse aggregate morphological properties on the high-temperature performance of asphalt mixtures. A modified Los Angeles (LA) abrasion test was employed to produce aggregates with various morphological properties by applying abrasion cycles of 0, 200, 400, 600, 800, 1000, and 1200 on crushed angular aggregates. Based on a laboratory-developed Morphology Analysis System for Coarse Aggregates (MASCA), the morphological properties of the coarse aggregate particles were quantified using the index of fractal dimension. The high-temperature performances of the dense-graded asphalt mixture (AC-16), gap-graded stone asphalt mixture (SAC-16), and stone mastic asphalt (SMA-16) mixtures containing aggregates with different fractal dimensions were evaluated through the dynamic stability (DS) test and the penetration shear test in laboratory. Good linear correlations between the fractal dimension and high-temperature indexes were obtained for all three types of mixtures. Moreover, the results also indicated that higher coarse aggregate angularity leads to stronger high-temperature shear resistance of asphalt mixtures.

Experimental Research on Road Performance of Natural Asphalt Modified Asphalt Mixtures

2011 ◽  
Vol 287-290 ◽  
pp. 762-766
Author(s):  
Liang Fan ◽  
Xiao Jin Song ◽  
Yu Zhen Zhang
Keyword(s):  
High Temperature ◽  
Asphalt Mixture ◽  
Cost Effective ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Pavement Performance ◽  
Modified Asphalt ◽  
Modification Technique ◽  
Road Performance ◽  
Natural Asphalt

This report mainly evaluated the pavement performance of natural asphalt from Albania. Firstly, base asphalts were processed with natural asphalt by “wet method” modification technique to obtain modified asphalt; and mixture are produced with these modified asphalt binders, and then high temperature performance and moisture stability properties are evaluated by some standard methods. Analysis shows that this natural asphalt can remarkably improve the high temperature and moisture stabilities of asphalt mixture, and own cost-effective advantage.

Rheology, Deformational Properties and Fatigue of the Asphalt Mixtures

2014 ◽  
Vol 875-877 ◽  
pp. 578-583 ◽  
Author(s):  
Frantisek Schlosser ◽  
Erika Sramekova ◽  
Juraj Šrámek
Keyword(s):  
Construction Management ◽  
Positive Impact ◽  
Flexible Pavements ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Hydrate Lime ◽  
Ground Rubber ◽  
Different Types

The deformational properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The Two-point Bending Test was used for determination of deformational characteristics of asphalt mixtures on Department of Construction Management in Zilina. The results are evaluated with the KATEMS assessment software. The long-term research lead to estimation of deformational characteristics and fatigue of different types of asphalt mixtures. The tests have shown a positive impact of additives (ground rubber, hydrate lime component) on the results of these mixtures. This article is focused on assessment of deformational properties and fatigue of selected types of asphalt mixtures.

Long-Term Experience of Running Operation Boilers Equipped with Furnace Working upon High-Temperature Circulating Fluidized Bed

2015 ◽  
Vol 792 ◽  
pp. 345-350
Author(s):  
Andrey Lesnykh ◽  
Sergey Golovatiy ◽  
Danil Valovik
Keyword(s):  
High Temperature ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
High Temperature Furnace ◽  
Different Types ◽  
Operational Tests ◽  
Adjustment System ◽  
Long Term Experience ◽  
Temperature Furnace

The boiler KE-10-14 reconstructed under high-temperature furnace circulation fluidized bed has been considered. Features of the boiler with a high-temperature furnace circulation fluidized bed have been presented. The characteristics of the boiler and problem of its operation for the whole period of operation have been shown. Recommendations for improving the efficiency of boiler have been developed on the basis of conducted operational tests. The results of adjustment system sectional blast have been presented. The characteristics of the boiler on different types of coal have been compared. The application of HTCFB furnace as well as carry out commissioning activities has made it possible to increase the effectiveness of the KE-10-14 boiler.

Rheological Properties of Asphalt Mixtures with Additives Based on Renewable Sources

2014 ◽  
Vol 1001 ◽  
pp. 177-182
Author(s):  
Frantisek Schlosser ◽  
Dominika Ďureková
Keyword(s):  
Rheological Properties ◽  
Construction Management ◽  
Positive Impact ◽  
Flexible Pavements ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Viscoelastic Materials ◽  
Different Types

The deformational properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The Two-point Bending Test was used for determination of deformational characteristics of asphalt mixtures on Department of Construction Management in Žilina. The results are evaluated with the KATEMS assessment software. The long-term research leads to estimation of deformational characteristics and fatigue of different types of asphalt mixtures. The tests have shown a positive impact of additives (ground rubber, hydrate lime component, recycling materials,...) on the results of these mixtures. This article is focused on assessment of deformational properties and fatigue of selected types of asphalt mixtures, there are viscoelastic materials in construction of pavement.

scholarly journals Effect of Rejuvenators on the Workability and Performances of Reclaimed Asphalt Mixtures

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6385
Author(s):  
Wei Tang ◽  
Xin Yu ◽  
Ning Li ◽  
Fuqiang Dong ◽  
Zhongyuan Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Stability ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Void Content ◽  
High Temperature Stability ◽  
Moisture Susceptibility ◽  
Reclaimed Asphalt ◽  
Air Void ◽  
Air Void Content

The use of rejuvenators has enhanced the workability of asphalt mixtures containing the reclaimed asphalt pavement (RAP). This conclusion is based on the determination of viscosity of asphalt binders, while not validated from reclaimed asphalt mixtures. In this study, the effect of two rejuvenators (ordinary and emulsified rejuvenator) on the workability of reclaimed asphalt mixtures was evaluated by measuring the mixing torque and determining the air void content of reclaimed mixtures. In addition, their effects on the performances of reclaimed mixture were studied via the three indexes tests, rutting test and freeze-thaw splitting tests. The experimental results show that mixing torque and air void content of reclaimed mixtures with the emulsified rejuvenator is 4% and 6% lower than that with the ordinary rejuvenator, respectively. This indicates that improvement of the workability of reclaimed mixtures can be achieved by using an emulsified rejuvenator, but not by an ordinary rejuvenator. That is also the reason that at least 20% greater high-temperature stability is found for reclaimed mixtures by using the emulsified rejuvenator than using the ordinary rejuvenator. In addition, reclaimed mixtures with the emulsified rejuvenator show similar moisture susceptibility to that with the ordinary rejuvenator. This study provides a feasible method to assess the workability effect of rejuvenators on reclaimed mixtures directly and recommends the use of an emulsified rejuvenator to improve the workability and high-temperature stability of reclaimed mixtures.

scholarly journals Influence of Selected Warm Mix Asphalt Additives on Cracking Susceptibility of Asphalt Mixtures

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 202 ◽  
Author(s):  
Marcin Stienss ◽  
Cezary Szydlowski
Keyword(s):  
Low Temperature ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Test Results ◽  
Specimen Test ◽  
Low Temperature Cracking ◽  
Long Term Performance ◽  
Term Performance

Warm mix asphalt (WMA) has been widely accepted as a future asphalt paving technology. Besides clear advantages, there are still some concerns regarding durability and long-term performance of pavements made with this type of asphalt mixtures. One of the most important issues is low temperature behaviour of WMA because certain additives used for temperature reduction can affect bitumen properties. This paper presents the evaluation of low-temperature properties of laboratory-produced asphalt concrete for wearing course with selected WMA additives. One type of bitumen with paving grade 50/70 and five WMA additives of different nature (organic, surface tension reducer and combination of both) were used in this study. The production and compaction temperature of mixtures containing WMA additives was 25 °C lower in comparison with the temperature of the reference mix. To assess the susceptibility of WMA to low-temperature cracking, Semi-Circular Bending (SCB) and Thermal Stress Restrained Specimen Test (TSRST) were used. Supplementary rating was made by analysing Bending Beam Rheometer (BBR) test results of asphalt binders.

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