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

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.

Download Full-text

Effect of Binder Types on Engineering Properties and Performance of Porous Asphalt Concrete

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2293-07 ◽

2012 ◽

Vol 2293 (1) ◽

pp. 55-62 ◽

Cited By ~ 8

Author(s):

Jian-Shiuh Chen ◽

Yang-Chou Sun ◽

Min-Chih Liao ◽

Chien-Chung Huang

Keyword(s):

Asphalt Concrete ◽

High Speed ◽

Asphalt Binder ◽

Aggregate Size ◽

High Viscosity ◽

Engineering Properties ◽

Maximum Aggregate Size ◽

Porous Asphalt ◽

Modified Binder ◽

Porous Asphalt Concrete

Porous asphalt concrete (PAC) has an open-graded aggregate mixture to yield high air voids; PAC is mainly applied to the surface drainage layer on high-speed trafficked highway pavements. The objective of the study was to investigate the effect of binder types on the engineering properties and field performance of PAC mixtures. Three binder types were selected for a 19-mm nominal maximum aggregate size gradation: conventional asphalt AR-80, polymer-modified asphalt, and high-viscosity asphalt. A series of laboratory tests were conducted to evaluate the engineering properties of the PAC mixture, including permeability, resistance to draindown, resistance to disintegration, resistance to rutting, and resistance to indirect traction. A 3-km in-service test road was constructed to monitor the performance of PAC pavements using these three binders. Polymer-modified binder was shown to minimize abrasion loss and enhance the durability of the PAC mixture. Test results indicated that the use of polymer-modified binder, instead of unmodified binder, reduced rutting and raveling. When the mixture contained high-viscosity binder, it showed the best performance in the field. Field measurements indicated improved drainage as a result of replacement of the conventional asphalt AR-80 binder with the polymer-modified and high-viscosity binders. PAC pavement surfaces provided good frictional characteristics once the asphalt binder film was worn from the aggregate.

Download Full-text

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.

Download Full-text

Evaluation air void content of drilled porous asphalt mixture cores using non-destructive X-ray computed tomography

10.1201/9781003222880-5 ◽

2021 ◽

pp. 48-58

Author(s):

T. Vieira ◽

J. Lundberg ◽

O. Eriksson ◽

A. Guarin ◽

S. Gong ◽

...

Keyword(s):

Computed Tomography ◽

Asphalt Mixture ◽

Void Content ◽

Porous Asphalt ◽

X Ray ◽

X Ray Computed ◽

Air Void ◽

Non Destructive ◽

Air Void Content

Download Full-text

The Effect of Compaction Temperatures and Numbers on the Air Void Level of Porous Asphalt Pavements

10.52460/issc.2021.014 ◽

2021 ◽

Author(s):

Ahmet Buğra İbiş ◽

Burak Şengöz ◽

Ali Topal ◽

Derya Kaya Özdemir

Keyword(s):

Heavy Traffic ◽

Experimental Studies ◽

Asphalt Mixture ◽

Hollow Structure ◽

Asphalt Pavements ◽

Void Content ◽

Porous Asphalt ◽

Compaction Energy ◽

Air Void ◽

Air Void Content

Porous asphalt pavement is defined as an asphalt concrete that is designed with open gradation aggregate which helps in removing the water with an air void content of about 20% by creating drainage channels. Open gradation consists of large amounts of coarse aggregates and small amounts of fine aggregates. The water is drained due to this hollow structure, this air void content in the porous asphalt mixture which inevitably decreases with time is the main parameter affecting the service life as well as the structural and functional performance. Moreover, the reduction in air void content is one of the main reasons for the loss of permeability in porous asphalt pavements and this lead to the increase in pavement density under heavy traffic conditions. Each country has its own technical asphalt specification involving the required compaction energy and temperature. This study involves the effect of compaction temperatures and numbers on the air void in porous asphalt pavements prepared with 50/70 penetration grade bitumen. As a result of experimental studies, it has been observed that the reduced compaction temperature and the number of compaction (energy) increase the air void level in porous asphalt pavements.

Download Full-text

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

Download Full-text

Dynamic Modulus of Porous Asphalt and the Effect of Moisture Conditioning

Materials ◽

10.3390/ma12081230 ◽

2019 ◽

Vol 12 (8) ◽

pp. 1230 ◽

Cited By ~ 5

Author(s):

Tan Hung Nguyen ◽

Jaehun Ahn ◽

Jaejun Lee ◽

Jin-Hwan Kim

Keyword(s):

Dynamic Modulus ◽

Asphalt Binder ◽

Asphalt Mixture ◽

Void Content ◽

Water Tank ◽

Porous Asphalt ◽

Air Void ◽

Frequent Exposure ◽

Air Void Content ◽

Selection Of

Porous asphalt has been used for permeable pavement to improve safety of roadways and the effectiveness of storm water management. As a surface drainage layer with frequent exposure to water, this material is affected by moisture. In this study, dynamic modulus tests were performed on both moisture unconditioned and conditioned specimens to characterize viscoelastic properties of porous asphalt mixture. The dynamic modulus values of porous asphalt materials with air void content of 9.0% and 20.5% were investigated at dry condition and after specified moisture conditioning cycles. One cycle of moisture conditioning procedure included placing specimens in water tank at 60 °C for 24 h, and then in another water tank at 25 °C for additional 2 h. The results showed that porous asphalt mixture with lower air void content resulted in higher values of dynamic modulus, and these values of porous asphalt with air void content of 9.0% was about 1.5 to 3.0 times that of porous asphalt with air void content of 20.5%. Higher value of the first number of performance graded binder (average 7-day maximum pavement design temperature) seems to make the dynamic modulus values at high temperatures larger. After moisture conditioning, the dynamic modulus of porous asphalt mixture increased, overall, especially at low temperatures. The appropriated selection of asphalt binder, a weakening of asphalt due to moisture damage can be reduced.

Download Full-text

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.

Download Full-text

Sound absorption characteristics of porous asphalt concrete pavements

Canadian Journal of Civil Engineering ◽

10.1139/l09-142 ◽

2010 ◽

Vol 37 (2) ◽

pp. 273-278 ◽

Cited By ~ 9

Author(s):

Sungho Mun

Keyword(s):

Asphalt Concrete ◽

Sound Absorption ◽

Traffic Noise ◽

Void Content ◽

Concrete Pavements ◽

Aggregate Gradation ◽

Porous Asphalt ◽

Noise Measurements ◽

Porous Asphalt Concrete ◽

Absorption Characteristics

This study investigates the sound absorption characteristics of porous asphalt concrete (PAC) pavements using an impedance tube to assess noise reduction performance. It is clearly shown that an improved attenuation of sound wave energy is achieved by adjusting the air void content, aggregate gradation, and PAC pavement thickness, based on measurements of sound absorption coefficients. In addition, traffic noise measurements taken from PAC pavements in the field are compared to those taken from dense-graded asphalt concrete (DGAC), which is widely used in pavement materials.

Download Full-text

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

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1590-11 ◽

1997 ◽

Vol 1590 (1) ◽

pp. 89-98 ◽

Cited By ~ 15

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.

Download Full-text