Chemomap Imaging Microscopy Use to in Situ Assess Oxidative Ageing in Compacted Asphalt Mixtures

In situ thermal-oxidative ageing tests by electron spin resonance (ESR) evidence that polydopamine (PDA) deposited onto clay can act as excellent radical-scavenger and thus significantly diminish the thermolysis of styrene butadiene rubber (SBR).

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Stiffness Identification of Foamed Asphalt Mixtures with Cement, Evaluated in Laboratory and In Situ in Road Pavements

Materials ◽

10.3390/ma13051128 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1128 ◽

Cited By ~ 2

Author(s):

Lukasz Skotnicki ◽

Jarosław Kuźniewski ◽

Antoni Szydlo

Keyword(s):

Asphalt Mixtures ◽

Base Layer ◽

Reclaimed Asphalt Pavement ◽

Reclaimed Asphalt ◽

Road Pavement ◽

Foamed Asphalt ◽

Fatigue Durability ◽

Hydraulic Binder ◽

Correlation Factors

The article presents the possibilities of using foamed asphalt in the recycling process to produce the base layer of road pavement constructions in Polish conditions. Foamed asphalt was combined with reclaimed asphalt pavement (RAP) and hydraulic binder (cement). Foamed asphalt mixtures with cement (FAC) were made, based on these ingredients. To reduce stiffness and cracking in the base layer, foamed asphalt (FA) was additionally used in the analyzed mixes containing cement. The laboratory analyzes allowed to estimate the stiffness and fatigue durability of the conglomerate. In the experimental section, measurements of deflections are made, modules of pavement layers are calculated, and their fatigue durability is determined. As a result of the research, new fatigue criteria for FAC mixtures and correlation factors of stiffness modules and fatigue durability in situ with the results of laboratory tests are developed. It is anticipated that FAC recycling technology will provide durable and safe road pavements.

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Investigation of top-down cracking performance of in-situ asphalt mixtures based on accelerated pavement testing and laboratory tests

Construction and Building Materials ◽

10.1016/j.conbuildmat.2018.05.165 ◽

2018 ◽

Vol 179 ◽

pp. 277-284 ◽

Cited By ~ 4

Author(s):

Zexin Ma ◽

Liping Liu ◽

Lijun Sun

Keyword(s):

Laboratory Tests ◽

Asphalt Mixtures ◽

Top Down ◽

Accelerated Pavement Testing ◽

Cracking Performance ◽

Pavement Testing

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Fatigue in asphalt mixtures – a summary to understand the complexity of its mathematical modeling

Journal of Physics Conference Series ◽

10.1088/1742-6596/2118/1/012009 ◽

2021 ◽

Vol 2118 (1) ◽

pp. 012009

Author(s):

H A Rondón-Quintana ◽

F A Reyes-Lizcano ◽

C A Zafra-Mejía

Keyword(s):

Mathematical Modeling ◽

Asphalt Mixtures ◽

Asphalt Pavements ◽

Physical Parameters ◽

Rest Periods ◽

Mode Stress ◽

Load Mode ◽

Mathematical Equations ◽

Foregoing Paper

Abstract Based on the reviewed literature in relation to the phenomenon of fatigue in asphalt mixtures, the foregoing paper depicts and describes in summary, the main variables that impact in the generation of said phenomenon in asphalt pavements. This has the purpose of showing its complexity to mathematically model it. As a general conclusion obtained in the study, it was found that the calibration difficulty of the models is mainly since the mathematical equations must be in capacity of considering that fatigue resistance of asphalt mixtures depends on load mode (stress-controlled or strain- controlled), the type of load (haversine or sinusoidal) and the rest periods to which laboratory samples are subjected. Additionally, both in situ, as within the laboratory, this varies with stiffness, volumetric composition (type and content of asphalt and aggregate), the geometry of samples, with effects associated to mix durability and environmental conditions, with the type of test, border conditions and support layers (base, subbase, subgrade). If these physical parameters are not considered, the mathematical equations lose reliability.

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OPTIMIZING ASPHALT MIXTURES TO BE HEATED BY MICROWAVE

Proceedings 17th International Conference on Microwave and High Frequency Heating ◽

10.4995/ampere2019.2019.9945 ◽

2019 ◽

Cited By ~ 1

Author(s):

Juan Gallego ◽

Federico Gulisano ◽

Luis Picado ◽

Joao Crucho

Keyword(s):

Microwave Radiation ◽

Real Option ◽

Structural Parameters ◽

Asphalt Binder ◽

Asphalt Mixture ◽

Asphalt Mixtures ◽

Heating Process ◽

Self Healing ◽

Bituminous Mixtures

Over the last ten years the concept of self healing in asphalt mixtures for roads pavements has been reaching great importance due to the fact that this capability allows a material to recuperate original properties after failure. This new generation of asphalt paving materials would allow road agencies to save no renewable resources as aggregates and bitumen, making the road investments more efficient. By the moment, there are two mechanisms to promote self healing in asphalt pavement: the incorporation in the asphalt mixtures of capsules containing a rejuvenating agent, or the heating of the pavement, especially the surface layer, to melt the asphalt binder, that gets liquid and refills the cracks in the material, recuperating a part of its initial structural parameters. Probably the most promising method for the in situ heating of the pavements is the radiation by microwaves. Unfortunately, asphalt mixture components (aggregates and binder) are low sensitive to microwave energy. This is why it may be advantageous to incorporate in the mixture additives to improve the sensibility to the radiation with microwaves. In this investigation two additives were studied: graphene and EAF slag coming from the steel industry. These additives were incorporated at several contents and the efficiency of the heating process was evaluated by the ratio kwh/kg/ºC in order to optimize the content of the additive in the asphalt mixture. Additionally, an evaluation of the electrical conductivity of the asphalt mixture at different contents of additives was carried out to study the possible relation between the conductivity of the mixture and its sensibility to microwave radiation. As a result of the investigation, it seems that microwave radiation can be a real option to promote in situ self healing of asphalt pavements. References J. Gallego, M.A. del Val, V. Contreras, A. Páez. Use of additives to improve the capacity of bituminous mixtures to be heated by means of microwaves, Materiales de Construcción. Vol. 67, Issue 325, January–March 2017, e110. http://dx.doi.org/10.3989/mc.2017.00416 …

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Rendez vous with Saturn's rings

International Astronomical Union Colloquium ◽

10.1017/s0252921100101885 ◽

1984 ◽

Vol 75 ◽

pp. 743-759 ◽

Cited By ~ 2

Author(s):

Kerry T. Nock

Keyword(s):

Solar Energy ◽

Electric Propulsion ◽

Power Source ◽

Propulsion System ◽

Low Thrust ◽

Ring Plane ◽

The Earth ◽

Total Impulse ◽

Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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