scholarly journals Fracture Behavior of Permeable Asphalt Mixtures with Steel Slag under Low Temperature Based on Acoustic Emission Technique

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5090 ◽  
Author(s):  
Bing Zhu ◽  
Hanbing Liu ◽  
Wenjun Li ◽  
Chunli Wu ◽  
Chao Chai
Keyword(s):  
Acoustic Emission ◽  
Low Temperature ◽  
Real Time ◽  
Fracture Behavior ◽  
Steel Slag ◽  
Asphalt Mixtures ◽  
Control Group ◽  
Test Results ◽  
Coarse Aggregates ◽  
Splitting Test

Acoustic emission (AE), as a nondestructive testing (NDT) and real-time monitoring technique, could characterize the damage evolution and fracture behavior of materials. The primary objective of this paper was to investigate the improvement mechanism of steel slag on the low-temperature fracture behavior of permeable asphalt mixtures (PAM). Firstly, steel slag coarse aggregates were used to replace basalt coarse aggregates with equal volume at different levels (0%, 25%, 50%, 75%, and 100%). Then, the low-temperature splitting test with slow loading was used to obtain steady crack growth, and the crack initiation and propagation of specimens were monitored by AE technique in real time. From the low-temperature splitting test results, SS-100 (permeable asphalt mixtures with 100% steel slag) has the optimal low-temperature cracking resistance. Therefore, the difference of fracture behavior between the control group (permeable asphalt mixtures without steel slag) and SS-100 was mainly discussed. From the AE test results, a slight bottom-up trend of sentinel function was founded in the 0.6–0.9 displacement level for SS-100, which is different from the control group. Furthermore, the fracture stages of the control group and SS-100 could be divided based on cumulative RA and cumulative AF curves. The incorporation of 100% steel slag reduced the shear events and restrained the growth of shear cracking of the specimen in the macro-crack stage. Finally, the considerable drops of three kinds of b-values in the final phase were found in the control group, but significant repeated fluctuations in SS-100. In short, the fracture behavior of PAM under low temperature was significantly improved after adding 100% steel slag.

scholarly journals Laboratory Investigation of Carbon Black/Bio-Oil Composite Modified Asphalt

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4910
Author(s):  
Ping Zhang ◽  
Lan Ouyang ◽  
Lvzhen Yang ◽  
Yi Yang ◽  
Guofeng Lu ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Carbon Black ◽  
Influencing Factors ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Test Results ◽  
Modified Asphalt ◽  
Temperature Performance ◽  
Bio Oil

As environmentally friendly materials, carbon black and bio-oil can be used as modifiers to effectively enhance the poor high-temperature and low-temperature performance of base asphalt and its mixture. Different carbon black and bio-oil contents and shear time were selected as the test influencing factors in this work. Based on the Box–Behnken design (BBD), carbon black/bio-oil composite modified asphalt was prepared to perform the softening point, penetration, multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests. The response surface method (RSM) was used to analyze the test results. In addition, the base asphalt mixtures and the optimal performance carbon black/bio-oil composite modified asphalt mixtures were formed for rutting and low-temperature splitting tests. The results show that incorporating carbon black can enhance the asphalt’s high-temperature performance by the test results of irrecoverable creep compliance (Jnr) and strain recovery rate (R). By contrast, the stiffness modulus (S) and creep rate (M) test results show that bio-oil can enhance the asphalt’s low-temperature performance. The quadratic function models between the performance indicators of carbon black/bio-oil composite modified asphalt and the test influencing factors were established based on the RSM. The optimal performance modified asphalt mixture’s carbon black and bio-oil content was 15.05% and 9.631%, and the shear time was 62.667 min. It was revealed that the high-temperature stability and low-temperature crack resistance of the carbon black/bio-oil composite modified asphalt mixture were better than that of the base asphalt mixture because of its higher dynamic stability (DS) and toughness. Therefore, carbon black/bio-oil composite modified asphalt mixture can be used as a new type of choice for road construction materials, which is in line with green development.

scholarly journals Laboratory Evaluation on Performance of Fiber-Modified Asphalt Mixtures Containing High Percentage of RAP

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yuefeng Zhu ◽  
Yanwei Li ◽  
Chundi Si ◽  
Xiaote Shi ◽  
Yaning Qiao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Asphalt Binder ◽  
Temperature Stability ◽  
Asphalt Mixtures ◽  
Self Healing ◽  
Test Results ◽  
Moisture Susceptibility ◽  
Modified Asphalt ◽  
Modified Binders ◽  
Different Types

In recent years, the significant demand for sustainable paving materials has led to a rapid increase in the utilization of reclaimed asphalt pavement (RAP) materials. When RAP is mixed with virgin asphalt concrete, particularly when its percentage is high, performance of the binder and asphalt concrete can be adversely affected. For this reason, different types of additives need to be identified and evaluated beforehand to mitigate the adverse effects. In this study, different types of fiber materials were identified and selected as binder/mixture additives, including lignin fiber (LF), polyester fiber (PF), and basalt fiber (BF). Various samples of fiber-modified binders and asphalt mixtures with different RAP contents (0%, 20%, and 40%) were prepared and were evaluated using two sets of laboratory testing: (i) dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests were performed to study the rheological properties of fiber-modified binders; (ii) the wheel tracking test, bending creep test, moisture susceptibility test, fatigue test, and self-healing fatigue test were conducted to characterize the laboratory properties of fiber-modified RAP mixtures. Test results for the modified binders show that the BF-modified binder has the greatest positive effect on the high-temperature performance of the asphalt binder, followed by PF- and LF-modified binders. However, the virgin asphalt shows the best low-temperature property than the fiber-modified asphalt binder. Test results for the whole RAP mixtures show that all fibers have a significant effect on the properties (including high- and low-temperature stability, moisture susceptibility, fatigue, and self-healing ability) of RAP mixtures. Among them, adding BF shows the greatest improvement in high-temperature stability, fatigue resistance, and self-healing ability of RAP mixtures. LF is found to significantly enhance low-temperature properties, and PF can greatly improve the resistance to moisture damage of RAP mixtures. For high percentage of RAP using on sites, adding multiple additives may further enhance its durability.

Effect of Testing Configuration in Semi-Circular Bending Fracture of Asphalt Mixtures: Experiments and Statistical Analyses

2019 ◽  
Vol 2673 (5) ◽  
pp. 320-328 ◽  
Author(s):  
Gabriel Nsengiyumva ◽  
Yong-Rak Kim
Keyword(s):  
Fracture Behavior ◽  
Peak Load ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Statistical Analyses ◽  
Test Results ◽  
Scb Test ◽  
Transportation Agencies ◽  
Bending Fracture ◽  
Flexibility Index

The semi-circular bending (SCB) test is a simple, efficient, and easily applicable method in the pavement community to characterize fracture behavior. This makes it widely used as a quality control (QC) and quality assurance (QA) approach at several transportation agencies. However, public–private testing laboratories have implemented SCB test methods using different load-support fixture conditions with an insufficient understanding of how the conditions affect the results and testing variability. This could be particularly problematic when using SCB test results obtained from different load-support fixtures as QC–QA (or pass/fail) purposes. This study investigated the effect of SCB testing configurations on test results and their variability by conducting tests using six different load-support fixtures. Several fracture-related indicators such as fracture energy, flexibility index, peak load, and the coefficient of the cracking index resulting from the six different load-support fixtures were compared. Test results and statistical analyses showed that SCB tests generally showed repeatable results, whereas load-support fixtures can affect test results and their repeatability, thus care should be taken when choosing a testing fixture. The addition of roller springs generally increased the variability of the test results. It appears that the mid-span jig was detrimental to testing repeatability, and friction at the support should be avoided because it can erroneously increase fracture resistance with a higher variability.

scholarly journals Damage Fracture Characterization of Asphalt Mixtures Considering Freeze–Thaw Cycling and Aging Effects Based on Acoustic Emission Monitoring

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5930
Author(s):  
Liuxu Fu ◽  
Huanyun Zhou ◽  
Jing Yuan ◽  
Weiliang An ◽  
Xianhua Chen
Keyword(s):  
Acoustic Emission ◽  
Real Time ◽  
Early Stage ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Aging Effects ◽  
Cumulative Energy ◽  
Internal Damage ◽  
Freeze Thaw ◽  
Damage Characteristics

Freeze–thaw (F–T) cycling and aging effects are the main factors contributing to the deterioration of asphalt mixtures. The acoustic emission (AE) technique enables real-time detection regarding the evolution of internal damage in asphalt mixtures during the loading process. This study set out to investigate the effects of F–T cycling and aging on the damage characteristics of asphalt mixture under splitting loads. Firstly, the Marshall specimens were prepared and then exposed to various numbers of F–T cycles (one, three, five, and seven) and different durations of aging (short-term aging and long-term aging for 24, 72, 120 and 168 h), after which the specimens were loaded by means of indirect tensile (IDT) testing, and corresponding parameters were synchronously collected by the AE acquisition system during the fracture process. Finally, the energy, cumulative energy and peak frequency were selected to investigate the damage mechanisms of asphalt mixtures. The findings demonstrate that the AE parameters provided effective identification of the deterioration for all specimens in real-time, and that the F–T cycling and aging effects altered the damage characteristics of asphalt mixtures, causing early damage, exacerbating the formation of micro-cracks in the early stage, accelerating the expansion of macro-cracks and advancing the debonding between the asphalt and aggregates. The findings of this study provide further insight into the mechanism of F–T cycling and aging effects on the deterioration of asphalt mixture.

Evaluation of low temperature viscoelastic properties and fracture behavior of bio-asphalt mixtures

2016 ◽  
Vol 19 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Brian Hill ◽  
Daniel Oldham ◽  
Behzad Behnia ◽  
Elham H. Fini ◽  
William G. Buttlar ◽  
...  
Keyword(s):  
Low Temperature ◽  
Viscoelastic Properties ◽  
Fracture Behavior ◽  
Asphalt Mixtures

scholarly journals Influence of Selected Warm Mix Asphalt Additives on Cracking Susceptibility of Asphalt Mixtures

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 202 ◽  
Author(s):  
Marcin Stienss ◽  
Cezary Szydlowski
Keyword(s):  
Low Temperature ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Test Results ◽  
Specimen Test ◽  
Low Temperature Cracking ◽  
Long Term Performance ◽  
Term Performance

Warm mix asphalt (WMA) has been widely accepted as a future asphalt paving technology. Besides clear advantages, there are still some concerns regarding durability and long-term performance of pavements made with this type of asphalt mixtures. One of the most important issues is low temperature behaviour of WMA because certain additives used for temperature reduction can affect bitumen properties. This paper presents the evaluation of low-temperature properties of laboratory-produced asphalt concrete for wearing course with selected WMA additives. One type of bitumen with paving grade 50/70 and five WMA additives of different nature (organic, surface tension reducer and combination of both) were used in this study. The production and compaction temperature of mixtures containing WMA additives was 25 °C lower in comparison with the temperature of the reference mix. To assess the susceptibility of WMA to low-temperature cracking, Semi-Circular Bending (SCB) and Thermal Stress Restrained Specimen Test (TSRST) were used. Supplementary rating was made by analysing Bending Beam Rheometer (BBR) test results of asphalt binders.

scholarly journals Evaluation of the Cohesive Properties of SBS-Modified Binders at Low Temperatures

2021 ◽  
Vol 29 (1) ◽  
pp. 27-34
Author(s):  
Baha Vural Kök ◽  
Yunus Erkuş ◽  
Mehmet Yilmaz
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Asphalt Mixtures ◽  
Test Results ◽  
Adhesive Properties ◽  
Bending Beam Rheometer ◽  
Cohesive Properties ◽  
Modified Binders ◽  
Rheological Test ◽  
Butadiene Styrene

Abstract The durability, fatigue resistance, and low-temperature behavior of asphalt layers are greatly affected by the properties of bitumen. Therefore, the composition of bitumen is frequently modified to improve the performance of asphalt mixtures. Sty-rene-butadiene-styrene (SBS) has been the most often used additive recently. Researchers are trying to improve the cohesive and adhesive properties of binders by such polymer-based additives. In this study, 160/220 penetration grade bitumen and Kraton D 1101 SBS were used. The present study contains a new evaluation for determining the cohesive behavior of SBS-modified binders at -1°C, -3°C, and -5°C. The results of this evaluation were compared to conventional and rheological test results. Penetration, softening point, viscosity, dynamic shear rheometer, and bending beam rheometer tests were therefore conducted. Finally, the results of a low-temperature tensile test were found to be consistent with the results of the other tests; hence, they also confirm the cohesive behavior of SBS-modified binders at low temperatures.

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