scholarly journals Effect of Rejuvenators on the Workability and Performances of Reclaimed Asphalt Mixtures

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6385
Author(s):  
Wei Tang ◽  
Xin Yu ◽  
Ning Li ◽  
Fuqiang Dong ◽  
Zhongyuan Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Stability ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Void Content ◽  
High Temperature Stability ◽  
Moisture Susceptibility ◽  
Reclaimed Asphalt ◽  
Air Void ◽  
Air Void Content

The use of rejuvenators has enhanced the workability of asphalt mixtures containing the reclaimed asphalt pavement (RAP). This conclusion is based on the determination of viscosity of asphalt binders, while not validated from reclaimed asphalt mixtures. In this study, the effect of two rejuvenators (ordinary and emulsified rejuvenator) on the workability of reclaimed asphalt mixtures was evaluated by measuring the mixing torque and determining the air void content of reclaimed mixtures. In addition, their effects on the performances of reclaimed mixture were studied via the three indexes tests, rutting test and freeze-thaw splitting tests. The experimental results show that mixing torque and air void content of reclaimed mixtures with the emulsified rejuvenator is 4% and 6% lower than that with the ordinary rejuvenator, respectively. This indicates that improvement of the workability of reclaimed mixtures can be achieved by using an emulsified rejuvenator, but not by an ordinary rejuvenator. That is also the reason that at least 20% greater high-temperature stability is found for reclaimed mixtures by using the emulsified rejuvenator than using the ordinary rejuvenator. In addition, reclaimed mixtures with the emulsified rejuvenator show similar moisture susceptibility to that with the ordinary rejuvenator. This study provides a feasible method to assess the workability effect of rejuvenators on reclaimed mixtures directly and recommends the use of an emulsified rejuvenator to improve the workability and high-temperature stability of reclaimed mixtures.

Research on the Paving Performance of Montmorillonite/SBS Modified Asphalt Mixtures

2012 ◽  
Vol 204-208 ◽  
pp. 4143-4146
Author(s):  
Zhong Guo He ◽  
Xin De Tang ◽  
Wen Jun Yin ◽  
Yi Fan Sun ◽  
Zhong Bo Liu
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Asphalt Mixture ◽  
Temperature Stability ◽  
Asphalt Mixtures ◽  
High Temperature Stability ◽  
Moisture Susceptibility ◽  
Modified Asphalt ◽  
Sbs Modified Asphalt ◽  
Enhanced Stability

Montmorillonite/SBS composite modifed asphalts were prepared by mixing montmorillonite with SBS-modified asphalt, further the corresponding asphalt mixtures were obtained. The paving technical indexes of the mixture such as physical properties, moisture suscepyibility, and high temperature stability were tested, and compared with that of the corresponding SBS-modifed asphalt mixture and base asphalt mixture. The results demonstrate that the montmorillonite/SBS composite modifed asphalt mixture exhibites enhanced stability, improved flow value and moisture susceptibility, and increased high temperature stability.

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.

Use of Mechanistic Models to Investigate Fatigue Performance of Asphalt Mixtures

2015 ◽  
Vol 2507 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Jong-Sub Lee ◽  
Nelson Gibson ◽  
Y. Richard Kim
Keyword(s):  
Damage Model ◽  
Asphalt Mixtures ◽  
Fatigue Performance ◽  
Void Content ◽  
Continuum Damage ◽  
Direct Tension ◽  
Air Voids ◽  
Viscoelastic Continuum Damage ◽  
Air Void ◽  
Air Void Content

Effects of design air void contents, design voids in mineral aggregate (VMA), and in-place air voids on the fatigue performance of asphalt mixtures were investigated with mechanistic analyses based on the viscoelastic continuum damage (VECD) analyses and the mechanistic–empirical pavement analysis using the AASHTOWare Pavement ME Design program. The VECD analyses included the simplified viscoelastic continuum damage model at the material level and two structural models: ( a) layered viscoelastic analysis and ( b) layered viscoelastic pavement analysis for critical distresses. The mix design of a 2013 accelerated loading facility test lane was selected to develop the volumetric mix designs with the design air voids of 3%, 4%, and 5%, design VMAs of 13%, 14%, and 15%, and in-place air void contents of 5%, 7%, and 9% with the Bailey method. Dynamic modulus and direct tension cyclic fatigue tests were performed in accordance with the AASHTO TP 107 procedure. The test results showed that the linear viscoelastic property was affected by the design VMA, design air void content, and in-place air void content in order of sensitivity. Also, the damage states at failure determined from the damage characteristic curves and the mechanistic fatigue predictions had consistent trends as observed for the design VMA, in-place air void, and design air void content in rank of sensitivity. Finally, the design VMA, in-place air void, and design air void parameters were found to be sensitive in the mechanistic analyses, whereas the parameter that was most sensitive in the pavement mechanistic–empirical analysis was the in-place air void content.

scholarly journals Feasibility Evaluation of Preparing Asphalt Mixture with Low-Grade Aggregate, Rubber Asphalt and Desulphurization Gypsum Residues

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1481 ◽  
Author(s):  
Xiaoliang Zhang ◽  
Ben Zhang ◽  
Huaxin Chen ◽  
Dongliang Kuang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Crack Resistance ◽  
Asphalt Mixture ◽  
Temperature Stability ◽  
Asphalt Mixtures ◽  
Limestone Powder ◽  
Low Grade ◽  
High Temperature Stability ◽  
Temperature Crack

Road construction consumes great amounts of high-grade natural resources. Using low-grade natural rocks or some solid wastes as substitute materials is a hot topic. Considering this, the feasibility of using low-grade granite aggregate, solid waste-based filler (desulphurization gypsum residues, DGR) and binder (waste tire rubber modified asphalt, RMA) simultaneously in asphalt mixtures has been fully investigated in this research. The commonly used base asphalt and limestone powder (LP) filler were control groups. Material characteristics of raw materials mainly including micro-morphology, functional group, mineral phase, chemical composition and thermal stability were first evaluated in order to recognize them. Four asphalt mixtures (two asphalt binder and two filler) were then designed by standard Superpave method. Finally, a detailed investigation into the pavement performance of asphalt mixtures was carried out. The moisture damage resistance and low-temperature crack resistance were detected by the changing rules of stability, strength and fracture energy, and the high-temperature stability and fatigue performance were determined by wheel tracking test and indirect tensile (IDT) fatigue test, respectively. Results suggested that RMA and DGR both showed positive effects on the low-temperature crack resistance and fatigue property of the granite asphalt mixture. DGR also strengthened moisture stability. The contribution of RMA on high-temperature deformation resistance of the granite asphalt mixture was compelling. It can offset the insufficiency in high-temperature stability made by DGR. A conclusion can be made that asphalt mixture prepared with granite, DGR and RMA possesses satisfactory pavement performances.

scholarly journals Optimizing Gradation Design for Ultra-Thin Wearing Course Asphalt

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 189 ◽  
Author(s):  
Wentian Cui ◽  
Kuanghuai Wu ◽  
Xu Cai ◽  
Haizhu Tang ◽  
Wenke Huang
Keyword(s):  
High Temperature ◽  
Asphalt Mixture ◽  
Temperature Stability ◽  
Wear Test ◽  
Asphalt Mixtures ◽  
Skid Resistance ◽  
High Temperature Stability ◽  
Functional Layer ◽  
Rutting Resistance ◽  
Road Surfaces

In recent years, ultra-thin wearing course asphalt mixture has been widely used in the reconstruction of old road surfaces and the functional layer of new road surfaces due to its good road performance. To improve the rutting resistance of ultra-thin wearing course asphalt mixture, this research presents an Ultra-thin Wearing Course-10 (UTWC-10) asphalt mixture with good high-temperature stability and skid resistance based on the Taylor system standard mesh specifications. The Course Aggregate Void Filling (CAVF) method is used to design the UTWC-10 asphalt mixture, which is compared with two other traditional ultra-thin wearing course asphalt mixtures on the basis of different laboratory performance tests. The high-temperature rutting test data shows that the rutting dynamic stability (DS) index of the UTWC-10 asphalt mixture is much higher than that of traditional wearing course asphalt mixtures, as it has better high-temperature stability. Moreover, anti-sliding performance attenuation tests are conducted by a coarse aggregate polishing machine. The wear test results show that the skid resistance of the UTWC-10 asphalt mixture is promising. The anti-sliding performance attenuation test can effectively reflect the skid resistance attenuation trend of asphalt pavement at the long-term vehicle load. It is verified that the designed UTWC-10 asphalt mixture shows excellent high-temperature rutting resistance and skid resistance, as well as better low temperature crack resistance and water stability than the traditional wearing course asphalt mixtures.

scholarly journals Evaluation of High-Temperature Performance of Asphalt Mixtures Based on Climatic Conditions

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 535
Author(s):  
Yan Mu ◽  
Zhen Fu ◽  
Jian Liu ◽  
Chen Li ◽  
Wenhao Dong ◽  
...  
Keyword(s):  
High Temperature ◽  
Dynamic Stability ◽  
Asphalt Mixture ◽  
Temperature Stability ◽  
Climatic Conditions ◽  
Asphalt Mixtures ◽  
High Temperature Stability ◽  
Long Duration ◽  
Different Temperatures ◽  
Modified Formula

The dynamic stability of a rutting test does not optimally reflect the high-temperature stability of asphalt mixtures. In this study, a rutting test was performed over a long duration (4 h) at different temperatures (40, 50, 60, 70 °C) for three asphalt mixtures, namely, matrix AC-16, SMA-16, and modified AC-16 asphalt mixtures. Subsequently, the temperature rutting rate was obtained after considering the annual temperature conditions of Guangdong and Beijing in China. Because the conditions of the rutting test were different from that of the actual pavement, the rut depth was calculated using a modified temperature rutting rate. This modification considered four factors: wheel trace distribution, temperature, pavement thickness, and loading rate. The calculation of the temperature rutting rate considered the climatic conditions and utilized the rutting deformation data from hour 1–4 of the rutting tests, during which the asphalt mixture was in a stable creep period. Thus, the high-temperature stability of the asphalt mixture was reflected more scientifically by the temperature rutting rate than the dynamic stability. The high-temperature rut-resistance of the asphalt mixture was found to improve significantly after the introduction of two additives (anti-rutting agent and lignin fiber). The modified formula for rut depth can realistically predict the annual rutting depth for three asphalt mixtures in a one-way driving pavement.

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 Influence of Air Void Content on Moisture Damage Susceptibility of Asphalt Mixtures

2014 ◽  
Vol 2446 (1) ◽  
pp. 8-16 ◽  
Author(s):  
A. Varveri ◽  
S. Avgerinopoulos ◽  
C. Kasbergen ◽  
A. Scarpas ◽  
A. Collop
Keyword(s):  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Void Content ◽  
Damage Susceptibility ◽  
Air Void ◽  
Air Void Content
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