An Evaluation of Several Techniques for Measuring Air-void Content in Asphalt Concrete Specimens

1994 ◽  
Vol 22 (5) ◽  
pp. 424 ◽  
Author(s):  
DR Petersen ◽  
J Harvey ◽  
T Mills ◽  
C Scheffy ◽  
J Sousa ◽  
...  
Keyword(s):  
Asphalt Concrete ◽  
Void Content ◽  
Air Void ◽  
Air Void Content

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

2000 ◽  
Vol 1723 (1) ◽  
pp. 125-132 ◽  
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.

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

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

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

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
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.

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

1997 ◽  
Vol 1590 (1) ◽  
pp. 89-98 ◽  
Author(s):  
John Harvey ◽  
Bor-Wen Tsai
Keyword(s):  
Fatigue Life ◽  
Asphalt Concrete ◽  
Void Content ◽  
Aging Effects ◽  
Initial Stiffness ◽  
Asphalt Content ◽  
Flexural Beam ◽  
Air Void ◽  
Air Void Content

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.

Determination of the air void content of asphalt concrete mixtures using artificial intelligence techniques to segment micro-CT images

2021 ◽  
pp. 1-10
Author(s):  
Alexis Jair Enríquez-León ◽  
Thiago Delgado de Souza ◽  
Francisco Thiago Sacramento Aragão ◽  
Delson Braz ◽  
André Maués Brabo Pereira ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Asphalt Concrete ◽  
Ct Images ◽  
Void Content ◽  
Micro Ct ◽  
Artificial Intelligence Techniques ◽  
Concrete Mixtures ◽  
Air Void ◽  
Air Void Content

scholarly journals Influence of Nominal Maximum Aggregate Size and Aggregate Gradation on Pore Characteristics of Porous Asphalt Concrete

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1355 ◽  
Author(s):  
Wenke Huang ◽  
Xu Cai ◽  
Xiang Li ◽  
Wentian Cui ◽  
Kuanghuai Wu
Keyword(s):  
Asphalt Concrete ◽  
Aggregate Size ◽  
Image Processing Technique ◽  
Maximum Aggregate Size ◽  
Void Content ◽  
High Porosity ◽  
Porous Asphalt ◽  
Air Void ◽  
Porous Asphalt Concrete ◽  
Air Void Content

Porous asphalt concrete (PAC) has been used to improve the traffic conditions in rainy weather due to its high porosity. Aggregate size and gradation have great impact on the connected pore structure, which ultimately affects the permeability of porous asphalt concrete. In this paper, the topological properties of connective pores including pore area, pore circularity, equivalent pore diameter, and void network of porous asphalt concrete with different nominal maximum aggregate sizes and gradations were analyzed using x-ray computer tomography scans and the image processing technique. It was observed that the maximum aggregate sizes will not have significant effect on the percentage of connected pores to total pores for porous asphalt concrete. Furthermore, the percentage of connected pores to total pores is related to the air void content, but for PAC-13 with 20% target air void content or above, the connectivity does not seem to have a sharp increase. Additionally, porous asphalt concrete with a smaller nominal particle size or lower target air void content seems to generate a more concentrated distribution of Eqdiameter. Moreover, pore circularities for porous asphalt concrete with a maximum aggregate size of 10 mm or above are independent of maximum aggregate sizes. Air void contents ranging from 16% to 21% do not have a significant effect on the voids’ circularity. Furthermore, the branching nodes in porous asphalt concrete with a smaller nominal maximum aggregate size or lower target air void content have a more uniform spatial distribution. However, the percentage of cross-linked number to total node raises as the nominal maximum aggregate size or target air void content increases.

scholarly journals A GPR-Based Pavement Density Profiler: Operating Principles and Applications

2021 ◽  
Vol 13 (13) ◽  
pp. 2613
Author(s):  
Nectaria Diamanti ◽  
A. Peter Annan ◽  
Steven R. Jackson ◽  
Dylan Klazinga
Keyword(s):  
Asphalt Pavement ◽  
Wave Impedance ◽  
Asphalt Mixtures ◽  
Void Content ◽  
Air Voids ◽  
New Instrument ◽  
Pavement Engineering ◽  
And Performance ◽  
Air Void ◽  
Air Void Content

Density is one of the most important parameters in the construction of asphalt mixtures and pavement engineering. When a mixture is properly designed and compacted, it will contain enough air voids to prevent plastic deformation but will have low enough air void content to prevent water ingress and moisture damage. By mapping asphalt pavement density, areas with air void content outside of the acceptable range can be identified to predict its future life and performance. We describe a new instrument, the pavement density profiler (PDP) that has evolved from many years of making measurements of asphalt pavement properties. This instrument measures the electromagnetic (EM) wave impedance to infer the asphalt pavement density (or air void content) locally and over profiles.

scholarly journals Study of High-Temperature Properties of Asphalt Mixtures Used for Bridge Pavement with Concrete Deck

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4238
Author(s):  
Piotr Pokorski ◽  
Piotr Radziszewski ◽  
Michał Sarnowski
Keyword(s):  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Binder Content ◽  
Void Content ◽  
Concrete Bridge ◽  
Asphalt Mixes ◽  
Protective Layers ◽  
Concrete Bridge Decks ◽  
Air Void ◽  
Air Void Content

The paper presents the issue of resistance to permanent deformations of bridge pavements placed upon concrete bridge decks. In Europe, bridge asphalt pavement usually consists of a wearing course and a protective layer, which are placed over the insulation (waterproofing). Protective layers of bridge pavement are commonly constructed using low air void content asphalt mixes as this provides the suitable tightness of such layers. Due to increased binder content, asphalt mixes for bridge pavement may have reduced resistance to permanent deformations. The article presents test results of resistance to permanent deformations of asphalt mixes for the protective layers. In order to determine the composition of mixtures with low air void content and resistance to permanent deformation, an experimental design was applied using a new concept of asphalt mix composition. Twenty-seven different asphalt mixture compositions were analyzed. The mixtures varied in terms of binder content, sand content and grit ratio. Resistance to permanent deformation was tested using the laboratory uniaxial cyclic compression method (dynamic load creep). On the basis of experimental results and statistical analysis, the functions of asphalt mixture permanent deformation resistance were established. This enabled a determination of suitable mixture compositions for protective layers for concrete bridge decks.

Impact of Specimen Configuration and Characteristics on Illinois Flexibility Index

2018 ◽  
Vol 2672 (28) ◽  
pp. 383-393 ◽  
Author(s):  
Jose Rivera-Perez ◽  
Hasan Ozer ◽  
Imad L. Al-Qadi
Keyword(s):  
Correction Factor ◽  
Loading Rate ◽  
Void Content ◽  
Displacement Curve ◽  
Specimen Thickness ◽  
Index Test ◽  
Notch Length ◽  
Air Void ◽  
Flexibility Index ◽  
Air Void Content

The Illinois Department of Transportation adopted the Illinois Flexibility Index Test (I-FIT) to evaluate the cracking vulnerability of asphalt concrete (AC) mixtures that was often shown to increase with the addition of recycled materials such as reclaimed asphalt pavement and recycled asphalt shingles. The test consists of a semi-circular AC sample that has a notch, loaded along the symmetric axis. Fracture energy (FE), post-peak slope, and the flexibility index (FI) are computed from the load displacement curve. These results can be influenced by specimen geometry and test parameters such as loading rate, AC voids content, and so forth. Therefore, this study investigated the effect of notch length, specimen thickness, loading rate, and AC air void content on the I-FIT results. It was found that an increase in the specimen thickness or loading rate resulted in a steeper post-peak slope without affecting the FE. As a result, the FI decreased. An increase in the notch length or AC air void content resulted in a flatter post-peak slope, thus, increasing the FI. From the results, it was concluded that existing correction factors to address the variations caused by specimen thickness and air void content are appropriate. A correction factor to address notch length variations is proposed. A unique correction factor for loading rate could not be developed because of the varying rate dependency of each AC mixture.

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