scholarly journals Influence of Laboratory Long-Term Aging on Selected Fracture Parameters of Asphalt Mixtures

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 811
Author(s):  
Pavla Vacková ◽  
Jan Valentin ◽  
Majda Belhaj
Keyword(s):  
Asphalt Mixtures ◽  
Bending Test ◽  
Cracking Behavior ◽  
Reclaimed Asphalt ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Complex Information ◽  
Scb Test ◽  
Fracture Work

The paper presents the influence of laboratory aging simulation on fracture properties determined on 150 variants of asphalt mixtures. The fracture properties were determined by two different test approaches—semi-circular bending test (SCB test) and three-point bending test on beam specimens (3-PB test). The aging was simulated according to one of the methods defined in EN 12697-52 (storage of test specimens in chamber at temperature of 85 °C for 5 days). The evaluated group of variants covered asphalt mixtures for all road layers. The group was further divided according to used bituminous binder (unmodified vs. modified) and reclaimed asphalt content. The results showed that strength parameters (flexural strength and fracture toughness) increase with aging. It further shows that fracture work provides more complex information about the cracking behavior. For the aging indexes, it was found that for mixtures with modified binders and mixtures which did not contain reclaimed asphalt (RA), the values were higher. The aging indexes for fracture work showed different results for both performed tests.

scholarly journals Influence of Antistripping Additives and Rejuvenators on Healing Performance of Moisture-Damaged HMA

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Dae-Wook Park ◽  
Tam Minh Phan ◽  
Yeong-Min Kim
Keyword(s):  
Asphalt Mixture ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Moisture Resistance ◽  
Three Point Bending ◽  
Indirect Tensile ◽  
Damage Healing ◽  
Aged Binder

This study aims to evaluate the effect of different rejuvenators and antistripping agents on the healing performance of hot mix asphalt (HMA). Two damage HMA series (e.g., moisture damage and aged damage) were subjected to either induction or microwave heating. A PG64-22 virgin and aged binder were used and modified with several additives. Three long-term aged binders (e.g., PAV5, PAV15, and PAV20) were conducted by pressure aging vessel (PAV) test. The moisture damage series fabricating with a new binder was further categorized into four different freeze-thaw (FT) cycles (e.g., 0FT, 1FT, 3FT, and 5FT). Also, the aged series was fabricated with three different aged binders. A total of eight damage-healing cycles were applied to all asphalt mixtures, examined by the three-point bending test. The moisture resistance of modified asphalt mixture was examined by indirect tensile strength test. Overall, asphalt mixtures modified with either antistripping additives or rejuvenators not only obtained higher moisture resistance but also gained better healing performance under moisture damage. In addition, the study showed a probable correlation between moisture damage and long-term aging in terms of healing performance, such as PAV15 and 3FT cycles and PAV20 and 5FT cycles.

Evaluation of Viscoelastic and Fracture Properties of Asphalt Mixtures with Long-Term Laboratory Conditioning

2018 ◽  
Vol 2672 (28) ◽  
pp. 503-513 ◽  
Author(s):  
Reyhaneh Rahbar-Rastegar ◽  
Jo Sias Daniel ◽  
Eshan V. Dave
Keyword(s):  
Viscoelastic Properties ◽  
Complex Modulus ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Maximum Aggregate Size ◽  
Cracking Behavior ◽  
Fracture Properties ◽  
Fracture Parameters

Aging affects the properties of asphalt mixtures in different ways; increase of stiffness, decrease of relaxation capability, and the increase of brittleness, resulting in changes in cracking behavior of asphalt mixtures. In this study, ten plant-produced, lab-compacted mixtures with various compositions (recycled materials, binder grades, binder source, and nominal maximum aggregate size) are evaluated at different long-term aging levels (24 hours at 135°C, 5 days at 95°C, and 12 days at 95°C on loose mix and 5 days at 85°C on compacted specimens). The asphalt mixture linear viscoelastic properties (|E*| and δ) and master curve shape parameters measured from complex modulus testing and fracture properties (measured from disc-shaped compact tension and semi-circular bending fracture testing) are compared at different levels of aging. The results indicate that the mixture exposure time to aging is proportional to the dynamic modulus and phase angle changes. Generally, the fracture parameters of mixtures become worse when aging level changes from 5 to 12 days aging. In spite of the similar viscoelastic properties, the mixtures with 24 hours at 135°C and 12 days at 95°C aging do not show similar fracture parameters.

scholarly journals Properties of Asphalt Mixtures Using Reclaimed Asphalt Containing Polymer-Modified Binder and Technicoeconomical Considerations of Their Use

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Jan Mikolaj ◽  
Frantisek Schlosser ◽  
Lubos Remek ◽  
Martin Pitoňák ◽  
Juraj Šrámek
Keyword(s):  
Plastic Deformation ◽  
Laboratory Testing ◽  
Asphalt Mixtures ◽  
Pavement Management ◽  
Bending Test ◽  
Pavement Performance ◽  
Stiffness Modulus ◽  
Reclaimed Asphalt ◽  
Modified Binder

The article summarises findings from laboratory testing of asphalt mixtures using reclaimed asphalt containing polymer-modified binder and subsequent technicoeconomical considerations of their use in pavement management system. Tested mixtures had 0%, 15%, and 40% content of reclaimed asphalt (RA) containing polymer-modified bitumen (PMB) obtained by milling from surfacing layers of existing PA, AC11, and SMA11 pavement layers. A complete description of these mixtures is given, and testing methods used are described. The mixtures were tested for air void content, ITSR water sensitivity test, plastic deformation wheel tracking test, stiffness of the tested mixtures, and two-point bending test to ascertain fatigue. Concise and succinct conclusions from laboratory testing are derived and used as an input in the second part of the article. It is found that the addition of RA containing PMB increased stiffness modulus of the final mixture, which increases resistance to plastic deformation and leads to higher brittleness at low temperatures. It is found that virgin PMB also increases fatigue resistance as opposed to PMB content from reclaimed materials. In the second part of the article, findings from laboratory testing are addressed in the context of their practical use in pavement management. The key element identified, having a direct impact on pavement performance models, was the stiffness modulus for mixtures with different PMB-reclaimed asphalt contents. A method is described to evaluate pavement construction properties related to wearing course materials via the pavement performance model. Practical use of this method is described and applied in a case study. In this case study, the proposed method is used to evaluate the issues regarding practical use of asphalt mixtures with different ratios of reclaimed asphalt containing PMB and economic implications of their use. It is found that pavement performance of surfacing mixtures with reclaimed asphalt containing PMB is significantly better for plastic deformation at the cost of earlier initiation and progression of surface distress due to cracking and potholing. This paper suggests that due to cracking and potholing, periodic maintenance costs increase for pavements with reclaimed asphalt material containing PMB; however, they are outweighed by lower procurement cost and longer life expectancy due to slower plastic deformation of the pavement.

scholarly journals Fracture Behavior Analysis of Semi-Circular Bending Test

2019 ◽  
Vol 271 ◽  
pp. 03007
Author(s):  
David Renteria ◽  
Shadi Saadeh ◽  
Enad Mahmoud
Keyword(s):  
Fracture Behavior ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Random Generation ◽  
Crack Initiation And Propagation ◽  
Air Voids ◽  
Generation Technique ◽  
Initiation And Propagation ◽  
Scb Test

The objective of this paper is to investigate the effect of air voids on the fracture properties of asphalt mixtures using SCB test in Discrete Element Method (DEM). Superpave and Coarse Matrix High Binder (CMHB) mixtures gradation were used to generate the percentages of aggregate, mastic, and air voids within the specimens. Aggregates and air voids were randomly generated for each asphalt mixture case. Model results illustrate that the crack initiation and propagation is controlled by the location of the aggregate particles and air voids in the mixture. Additionally, the absence of air voids above the tip of the notch increases the stiffness of the sample and increase its resistance to failure. The novelty of using DEM and the random generation technique for generating numerical specimens proved to be a useful approach in investigating the properties of the mastic, aggregate and interface as they relate to fracture of asphalt mixtures.

Numerical Simulation of Three-Point Bending Test for Asphalt Mixtures

2022 ◽  
Author(s):  
Hongyan Ma ◽  
Peiyuan Cheng ◽  
Mengxi Lv ◽  
Liangliang Chen ◽  
Canlin Zhang
Keyword(s):  
Numerical Simulation ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Three Point Bending

Impact of Aging on the Viscoelastic Properties and Cracking Behavior of Asphalt Mixtures

2019 ◽  
Vol 2673 (6) ◽  
pp. 406-415 ◽  
Author(s):  
Runhua Zhang ◽  
Jo E. Sias ◽  
Eshan V. Dave ◽  
Reyhaneh Rahbar-Rastegar
Keyword(s):  
Viscoelastic Properties ◽  
Complex Modulus ◽  
Fatigue Cracking ◽  
Compact Tension ◽  
Asphalt Mixtures ◽  
Fatigue Properties ◽  
Cracking Behavior ◽  
Stiffness Reduction ◽  
Fracture Tests

Aging can significantly affect the viscoelastic properties and cracking behavior of asphalt mixtures, causing increase in stiffness, reduction in relaxation capability, and increase in brittleness. Eleven mixtures are evaluated using different laboratory conditioning protocols to evaluate how the properties of asphalt mixtures, including viscoelastic properties, fatigue, and fracture behavior will change over time. Comparisons between different aging levels and mixtures are conducted by using complex modulus (E*) (field cores are included), simplified viscoelastic continuum damage (S-VECD) approach, semi-circular bending (SCB), and disk shaped compact tension (DCT) fracture tests. The climatic aging index developed by the NCHRP 09-54 project is utilized in this study to calculate the appropriate field aging duration corresponding to the different laboratory aging protocols. Pavement evaluation tools FlexPAVETM and IlliTC are also used to predict and compare the fatigue and thermal cracking performance of these mixtures. The results of E* and S-VECD tests indicate that the mixtures are more prone to fatigue cracking with aging, and the two long-term conditioning protocols induce statistically similar changes in linear viscoelastic and fatigue properties. However, prediction of fatigue performance from FlexPAVE TM does not show a consistent trend once pavement structure and traffic are considered. Fracture tests and IlliTC predictions show the virgin mixtures and those with soft base binders will have better capability to resist cracking after long-term aging. In this study, the two mixtures with the largest difference between high and low temperature performance grade (PG) show the largest change in fracture and fatigue properties with aging.

Low Temperature Cracking Evaluation of Asphalt Rubber Mixtures Using Semi-Circular Bending Test

2011 ◽  
Vol 243-249 ◽  
pp. 4201-4206 ◽  
Author(s):  
Jing Hui Liu
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Asphalt Pavements ◽  
Dry Process ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Scb Test ◽  
Low Temperature Cracking

Low temperature cracking is the main distress in asphalt pavements in winter. As asphalt rubber course is increasing, there is no standard method to characterize the resistance to cracking of asphalt rubber mixtures. This paper investigates the use of a Semi Circular Bend (SCB) test as a candidate for a low-temperature cracking specification. Based on the SCB test, this paper presents the findings of a laboratory study that aimed to evaluate the effects of recycled tire rubber on the Low temperature cracking properties of asphalt mixtures. Three mix types, a conventional hot-mix asphalt concrete, a dry process rubber modified asphalt concrete, and a wet process asphalt-rubber asphalt concrete, were included in the investigation. It is found that the asphalt mixtures produced by the wet process showed much better low temperature crack resistance, the binder effect modified by rubber was significant.

scholarly journals Three-point bending study on the microscopic fracture behavior of pre-oxidized Cr-coated Zr-4 alloys

2021 ◽  
Vol 2076 (1) ◽  
pp. 012051
Author(s):  
Mingyue Du ◽  
Chenxue Wang ◽  
Jishen Jiang ◽  
Xianfeng Ma
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Fracture Behavior ◽  
Early Stage ◽  
Bending Test ◽  
Cracking Behavior ◽  
Three Point Bending ◽  
Crack Penetration ◽  
Cr Coating

Abstract In this study, an in situ three-point bending test was carried out to study the mechanical properties and cracking behavior of the Cr-coated Zr-4 alloy considering the effect of pre-oxidation. The results showed that high temperature pre-oxidation led to the formation of intermetallic ZrCr2 at the coating/substrate interface and an α-Zr(O) layer beneath the interface. During the three-point bending test, the Cr coating and Zr-4 substrate showed good plastic deformation. However, the brittle intermetallic ZrCr2 diffusion layer exhibited cracks in the early stage, which accelerated the crack penetration to the Cr coating and the Zr-4 substrate, leading to the pre-failure of the pre-oxidized sample.

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