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.

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

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.

Moisture Sensitivity of Asphalt Mixtures using Cycling Pore Pressure Conditioning

2019 ◽  
Vol 2673 (2) ◽  
pp. 294-303 ◽  
Author(s):  
Pajtim Sulejmani ◽  
Safwat Said ◽  
Sven Agardh ◽  
Abubeker Ahmed
Keyword(s):  
Pore Pressure ◽  
Complex Modulus ◽  
Moisture Damage ◽  
Climate Impacts ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Void Content ◽  
Premature Failure ◽  
Air Void ◽  
Air Void Content

One of the major causes of premature failure in asphalt pavements is moisture damage. Asphalt mixtures designed without considering climate impacts may suffer from durability problems caused by movement of water inside the asphalt mixture. Rolling traffic over wet pavement builds up pore pressure in the mixture, which will consequently accelerate deterioration. The objective of the study was to assess the moisture damage to asphalt concrete mixtures by means of complex modulus testing of dry and moisture-conditioned asphalt specimens with various mixture compositions. The asphalt mixtures were conditioned with the Moisture Induced Sensitivity Tester (MIST), which aims to replicate pore pressure in field conditions. The results showed a decline in stiffness modulus and a reduction in elastic properties after MIST conditioning. In addition, the results indicated that binder content and air void content had a significant influence on the reduction in stiffness. To capture the relationship between air void content, binder content, and the reduction in stiffness, a relationship was developed and validated with measurements on cores extracted in the field.

scholarly journals Dynamic Modulus of Porous Asphalt and the Effect of Moisture Conditioning

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1230 ◽  
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.

Effects of Aggregate Degradation on Air Voids of Structural Asphalt Mixture in Florida

1997 ◽  
Vol 1583 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Gale C. Page ◽  
James A. Musselman ◽  
David C. Romano
Keyword(s):  
Asphalt Mixture ◽  
Asphalt Pavements ◽  
Void Content ◽  
Unexpected Finding ◽  
Asphalt Mixes ◽  
Air Voids ◽  
The North ◽  
Florida Department ◽  
Air Void ◽  
The Impact

In an effort to further improve the rut resistance of asphalt pavements in Florida, the Florida Department of Transportation implemented specifications requiring that the production of asphalt mixes be stopped when the air-void content falls below a critical level. To address the problem of low air voids and rutting in north Florida, a proposal was made to reduce the maximum amount of material allowed to pass the 75-μm sieve (P-75μm) at design for asphalt mixtures containing north Florida limestone aggregates. A field study was then undertaken to determine whether this proposal would adequately resolve the problem of low air voids during production due to high P-75μm. The purpose of the study was to determine the amount of degradation to a typical north Florida limestone material and the subsequent effects that degradation has on air voids. The results indicate that although the north Florida limestone aggregates used in this study did degrade significantly, the asphalt contractor was, in general, able to control the amount of P-75μm material in the mix by wasting the baghouse fines. During production, the air voids were low on a number of samples. The source of these low air voids appears to be related to a combination of a high asphalt content in the mix as well as a high P-75μm content. The findings do not support the proposal to reduce the P-75μm content at design at this time. An unexpected finding of this study was that the bulk specific gravities of the commercial aggregate products were less than expected. The impact of this finding is that the voids in the mineral aggregate (VMA) of the mix at design would not meet minimum specification requirements. Although this could make it difficult for an asphalt mixture to have adequate air voids during production, the primary impact of a low VMA is that the pavement would have poor durability and would potentially become brittle and crack prematurely.

scholarly journals Asphalt Pavement Acoustic Performance Model

2019 ◽  
Vol 11 (10) ◽  
pp. 2938 ◽  
Author(s):  
Rita Kleizienė ◽  
Ovidijus Šernas ◽  
Audrius Vaitkus ◽  
Rūta Simanavičienė
Keyword(s):  
Noise Reduction ◽  
Noise Level ◽  
Asphalt Mixture ◽  
Low Noise ◽  
Asphalt Mixtures ◽  
Mixture Composition ◽  
Void Content ◽  
Road Noise ◽  
Air Void ◽  
Air Void Content

Low-noise pavements are used as an effective method of traffic noise mitigation. Low-noise pavements reduce the noise that arises due to interactions between tires and road surfaces (tire/road) via the implementation of three main components: low pavement roughness, negative pavement texture, and a high pavement air-void content. The tire/road noise reduction capabilities of the wearing layer vary depending on the aggregate type, gradation, bitumen and air-void content, and density. Consequently, the demand for an accurate tire/road noise prediction model has arisen from the design of asphalt mixtures. This paper deals with how asphalt mixture components of the wearing layer influence tire/pavement noise reduction and presents a model for tire/road noise level prediction based on the asphalt mixture composition. The paper demonstrates that the noise reduction level of low-noise asphalt pavements is dependent on the composition of the asphalt mixture. Asphalt wearing layer mixture composition parameters were tested in the laboratory from cores taken from 18 road sections, where acoustic properties were measured using a close-proximity (CPX) method. The proposed linear model is based on the bitumen amount, the air-void content of the mixture and aggregate shape and involves materials that comply with the general requirements for high-quality asphalt mixtures. The model allows for the prediction of the tire/road noise level at the asphalt mixture design stage using asphalt mixture components and volumetric properties. The proposed model is the first stage in the building of a complex model with a much wider range of low-noise asphalts components, pavement profile depth and CPX-value relationships.

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.

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