Long-Term Oven-Aging Effects on Fatigue and Initial Stiffness of Asphalt Concrete

An investigation of the effects of long-term oven aging (LTOA) on initial stiffness and fatigue of asphalt concrete was made using two typical California asphalts, known to have different aging characteristics, in mixes with one aggregate. Asphalt content, air-voids content, and days of LTOA were varied independently. Stiffness and fatigue were evaluated using the controlled-strain flexural beam test developed by the Strategic Highway Research Program Project A-003A. The results indicated that both mixes exhibited an increase in initial stiffness with LTOA periods of up to six days. The sensitivity of beam fatigue life to LTOA depended on the asphalt. Beams containing Valley asphalt had virtually no change in fatigue life due to LTOA, whereas beams with Coastal asphalt showed some sensitivity to LTOA. For both asphalts, the average reduction in fatigue life from 6 days of LTOA was less than that caused by a 3 percent increase in air-void content or a 1 percent decrease in asphalt content. Simulations of thick and thin pavement structures were performed to reconcile the effects of LTOA, asphalt content, and air-void content on mix fatigue life and stiffness by evaluating their combined effects on predicted pavement fatigue life. The simulations indicated that aging, as induced by LTOA, increased fatigue life for all cases except one.

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Effects of Asphalt Content and Air Void Content on Mix Fatigue and Stiffness

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198196154300105 ◽

1996 ◽

Vol 1543 (1) ◽

pp. 38-45 ◽

Cited By ~ 30

Author(s):

John T. Harvey ◽

Bor-Wen Tsai

Keyword(s):

Fatigue Life ◽

Primary Objective ◽

Mix Design ◽

Void Content ◽

Flexural Stiffness ◽

Clear Understanding ◽

Initial Stiffness ◽

Asphalt Content ◽

Air Void ◽

Air Void Content

The primary objective of most procedures for asphalt concrete mix design is to find an asphalt content that minimizes the possibility of stability failure while providing adequate fatigue and other durability characteristics. To date, the consequences of asphalt content selection and construction compaction on fatigue performance and flexural stiffness have not been thoroughly investigated and documented with experimental data. The results of laboratory-controlled strain flexural beam testing, (i.e., fatigue life and flexural stiffness) for one aggregate and asphalt cement combination, five asphalt contents, and three air void contents are presented. The results clearly indicate the benefits of a lower air void content on both fatigue life and initial stiffness. Increased asphalt content was found to increase fatigue life and reduce stiffness. Alternative models for predicting fatigue life and initial stiffness using asphalt content, air void content, voids filled with bitumen, and the volume concentrations of asphalt and aggregate were evaluated. Elastic-layer theory was used to simulate the effects of air void content and asphalt content on the fatigue life of several example overlays using the models for stiffness and fatigue life from the laboratory testing. The simulations indicated an increase in predicted pavement fatigue life for lower air void contents and higher asphalt contents. Example simulations of the effects of increased asphalt content and decreased air void content at the bottom of thick overlays indicated a marked increase in predicted fatigue life. It was also concluded that stiffness should not be included in regression for fatigue life models for mix design unless there is a clear understanding of the effects of other variables in the model that correlate with both fatigue life and stiffness.

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Field Performance of Foaming Warm Mix Asphalt Pavement

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198119832885 ◽

2019 ◽

Vol 2673 (3) ◽

pp. 281-294 ◽

Cited By ~ 5

Author(s):

Shenghua Wu ◽

Weiguang Zhang ◽

Shihui Shen ◽

Balasingam Muhunthan

Keyword(s):

Field Performance ◽

Warm Mix Asphalt ◽

Void Content ◽

Transverse Cracking ◽

Water Based ◽

Asphalt Content ◽

Air Void ◽

Air Void Content ◽

Term Field

Water-containing and water-based foaming warm mix asphalt (WMA) technologies have been widely used in recent years but their long-term field performance is scarcely documented. This paper summarizes the field performances of six water-containing foaming and 10 water-based foaming WMA pavements across the United States and compares them with corresponding hot mix asphalt (HMA) pavements. Two series of field distress surveys were conducted to measure wheel-path longitudinal cracking, transverse cracking, and rut depth. Field cores were extracted to measure the in-place air void content, aggregate gradation, and asphalt content. The volumetric properties and field performance of foaming WMA and HMA control pavements were evaluated. The foaming WMA pavements showed slightly higher in-place air void (i.e., lower in-place density) than the HMA pavements. It was also found that the foaming WMA pavements in general had comparable or more wheel-path longitudinal cracking than the HMA pavements. The long-term field performance of foaming WMA pavements for transverse cracking and rutting were found to be similar to control HMA pavements. The study also reinforced the importance of in-place air void and asphalt content, finding that slightly higher asphalt content and lower in-place air void content may be beneficial for long-term resistance to cracking of asphalt pavements. As a result of the findings, the optimal pavement maintenance time was estimated to be four to five years since paving for full-depth pavement projects.

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Specimen Geometry Study for Direct Tension Test Based on Mechanical Tests and Air Void Variation in Asphalt Concrete Specimens Compacted by Superpave Gyratory Compactor

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1723-16 ◽

2000 ◽

Vol 1723 (1) ◽

pp. 125-132 ◽

Cited By ~ 28

Author(s):

Ghassan R. Chehab ◽

Emily O’Quinn ◽

Y. Richard Kim

Keyword(s):

Asphalt Concrete ◽

Tensile Testing ◽

Complex Modulus ◽

Specimen Geometry ◽

Uniaxial Tensile ◽

Void Content ◽

Uniaxial Tensile Testing ◽

Superpave Gyratory Compactor ◽

Air Void ◽

Air Void Content

Reliable materials characterization and performance prediction testing of asphalt concrete requires specimens that can be treated as statistically homogeneous and representative of the material being tested. The objective of this study was to select a proper specimen geometry that could be used for uniaxial tensile testing. Selection was based on the variation of air void content along the height of specimens cut and cored from specimens compacted by the Superpave gyratory compactor (SGC) and on the representative behavior under mechanical testing. From measurement and comparison of air void contents in cut and cored specimens, it was observed for several geometries that sections at the top and bottom and those adjacent to the mold walls have a higher air void content than do those in the middle. It is thus imperative that test specimens be cut and cored from larger-size SGC specimens. Complex modulus and constant crosshead-rate monotonic tests were conducted for four geometries—75 × 115, 75 × 150, 100 × 150, and 100 × 200 mm—to study the effect of geometry boundary conditions on responses. On the basis of graphical and statistical analysis, it was determined that there was an effect on the dynamic modulus at certain frequencies but no effect on the phase angle. Except for 75 × 115 mm, all geometries behaved similarly under the monotonic test. From these findings and other considerations, it is recommended that the 75- × 150-mm geometry, which is more conservative, and the 100- × 150-mm geometry be used for tensile testing.

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Improved method of considering air void and asphalt content changes on long-term performance of asphalt concrete pavements

International Journal of Pavement Engineering ◽

10.1080/10298436.2013.857775 ◽

2013 ◽

Vol 15 (8) ◽

pp. 718-730 ◽

Cited By ~ 14

Author(s):

W.A. Zeiada ◽

K.E. Kaloush ◽

B.S. Underwood ◽

M.E. Mamlouk

Keyword(s):

Asphalt Concrete ◽

Concrete Pavements ◽

Improved Method ◽

Asphalt Content ◽

Long Term Performance ◽

Air Void ◽

Term Performance

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Assessing the Ageing Impact on Fatigue Life of Asphalt Concrete

Journal of Building Material Science ◽

10.30564/jbms.v2i2.2792 ◽

2021 ◽

Vol 2 (2) ◽

Author(s):

Saad Issa Sarsam

Keyword(s):

Fatigue Life ◽

Asphalt Concrete ◽

Concrete Slab ◽

Testing Temperature ◽

Environmental Condition ◽

Ageing Processes ◽

Before And After ◽

Short And Long Term ◽

Asphalt Content

The fatigue life of asphalt concrete is often related to environmental condition, loading condition, ageing, material composition and properties. This work investigates the influence of short and long term ageing of laboratory beam specimens, asphalt content, and testing temperature on fatigue life of asphalt concrete wearing course. Slab samples of (30 x 40x 6) cm have been prepared, beam specimens of (40x 5x 6) cm were cut from the asphalt concrete slab samples. Beam specimens were tested for fatigue life under the influence of three levels of micro strain (250, 400, and [3]750) at (5, 20, and 30) °C before and after practicing long-term aging. It was observed that the fatigue life decreases by (85 and 97) %, (87.5 and 97.4) %, (71.4 and 95.2) % after increasing the applied microstrain from (250 to 400 and 750) μƐ for control mixture and for mixtures subjected to short-and long-term ageing processes respectively. The fatigue life increases by (142.8 and 257.1) %, (34.4 and 57.8) % and (10 and 30) % when the asphalt content increases from (4.4 to 4.9 and 5.4) % for specimens practicing the applied microstrain of (250, 400 and 750) μƐ respectively. It was concluded that the fatigue life increases by a range of (two to fifteen) folds when the testing temperature increases from (5 to 20 and 30)°C respectively.

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Micro-Structure of Hot Mix Asphalt Containing the 35/50 Bitumen Viewed in Terms of Excess Moisture in the Underlying Course of Pavement

Materials ◽

10.3390/ma13102230 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2230

Author(s):

Paweł Mieczkowski ◽

Bartosz Budziński ◽

Robert Jurczak

Keyword(s):

Fatigue Life ◽

Moisture Content ◽

Hot Mix Asphalt ◽

Complex Modulus ◽

Point Of View ◽

Base Layer ◽

Void Content ◽

Base Course ◽

Air Void ◽

Air Void Content

Compaction of Hot Mix Asphalt (HMA) is a process aimed at obtaining the desired performance properties. Attainment of the required compaction can be hampered by external factors, which includes the presence of water. Water is known to cause quick lowering of the HMA temperature. The bottom face of the asphalt layers of a pavement is a sensitive point from the fatigue life point of view. In the site conditions, it is often difficult to obtain the required air void content at the bottom of an asphalt layer and excessive moisture content in the base course lying beneath the asphalt layer can be one of the causes. This article presents the results of tests carried out on a test section on which HMA was placed on an unbound aggregate base layer of varying moisture content. The material used for the binder course was asphalt concrete mixture composed of aggregate of minus 16 mm grading and 35/50 bitumen. Being relatively hard it is the most often specified bitumen for binder courses and also base courses. One of its characteristics is a considerable increase of viscosity with decreasing temperature, which hampers the process of compaction. The bulk specific gravity was measured to determine the variations in the air void content through the specimens. The complex modulus of elasticity and fatigue life were the other parameters which were determined on the specimens with different air void contents. The test results show worsening of the properties which have a decisive bearing on the service life of pavement.

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Characterization of the air void content of fine aggregate matrices within asphalt concrete mixtures

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.124214 ◽

2021 ◽

Vol 300 ◽

pp. 124214

Author(s):

Alexis Jair Enríquez-León ◽

Thiago Delgado de Souza ◽

Francisco Thiago Sacramento Aragão ◽

André Maués Brabo Pereira ◽

Liebert Parreiras Nogueira

Keyword(s):

Asphalt Concrete ◽

Void Content ◽

Fine Aggregate ◽

Concrete Mixtures ◽

Air Void ◽

Air Void Content

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Influences by Air Voids on the Low-Temperature Cracking Property of Dense-Graded Asphalt Concrete Based on Micromechanical Modeling

Advances in Materials Science and Engineering ◽

10.1155/2016/6942696 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

Tao Ma ◽

Yao Zhang ◽

Hao Wang ◽

Xiaoming Huang ◽

Yongli Zhao

Keyword(s):

Low Temperature ◽

Asphalt Concrete ◽

Three Dimensions ◽

Micromechanical Modeling ◽

Void Content ◽

Cracking Behavior ◽

Air Voids ◽

Low Temperature Cracking ◽

Air Void ◽

Air Void Content

This study characterized the impacts of air voids on the low-temperature cracking behavior of dense-graded asphalt concrete. Virtual low-temperature bending beam test for dense-graded asphalt concrete was built and executed by discrete element method and PFC3D (particle flow code in three dimensions). Virtual tests were applied to analyze the impacts by content, distribution, and size of air voids on the low-temperature properties of dense-graded asphalt concrete. The results revealed that higher air void content results in worse low-temperature property of dense-graded asphalt concrete, especially when the air void content exceeds the designed air content; even with the same designed air void content, different distributing condition of air voids within asphalt concrete leads to different low-temperature properties of asphalt concrete, especially when the air void content in the central-lower part of testing sample varies. Bigger size of single air void which tends to form interconnected air voids within asphalt concrete has more harmful impacts on the low-temperature properties of asphalt concrete. Thus, to achieve satisfied low-temperature properties of dense-graded asphalt concrete, it is critical to ensure the designed air void content, improve the distribution of air voids, and reduce the interconnected air voids for dense-graded asphalt concrete.

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