scholarly journals Self-Healing Analysis of Half-Warm Asphalt Mixes Containing Electric Arc Furnace (EAF) Slag and Reclaimed Asphalt Pavement (RAP) Using a Novel Thermomechanical Healing Treatment

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2502 ◽  
Author(s):  
José Manuel Lizárraga ◽  
Juan Gallego
Keyword(s):  
Mechanical Properties ◽  
Microwave Heating ◽  
Asphalt Pavement ◽  
Electric Arc ◽  
Asphalt Mixtures ◽  
Self Healing ◽  
Arc Furnace ◽  
Recycled Asphalt ◽  
Indirect Tensile ◽  
Eaf Slag

Nowadays, the self-healing of asphalt pavements promoted by microwave radiation heating energy is gaining attention and strength in the scientific community. However, most of these studies are only conceptual and, thus, remain shrouded in uncertainty regarding technology development, economy, and application effect. Therefore, there are several efforts underway to offer more effective assisted healing treatments that are capable of overcoming such uncertainties. This paper aims to assess and quantify the healing performance rates (HR) of half-warm recycled asphalt (HWRA) mixtures containing electric arc furnace (EAF) slag and total recycled asphalt pavement (RAP) rates. To this end, a novel assisted thermomechanical healing treatment (i.e., a recompaction-based technique and microwave heating energy) was put forward to promote the potential healing effect of this treatment on the mechanical properties of the asphalt mixtures. In order to do this, three microwave heating temperatures (25 °C, 60 °C, and 80 °C) and three mechanical recompaction levels (0, 25, and 50 gyrations) were selected. After that, the healing performance rates (%, HR) of the asphalt mixtures were calculated by repeated indirect tensile strength (ITS) and indirect tensile stiffness modulus (ITSM). The results indicated that the 8% EAF slag mixture was found to provide significant microwave heating energy savings by up to 69% compared with the benchmark 100% RAP mixture, and, at the same time, it experienced a remarkable stiffness recovery response of 140% of the initial mechanical properties. These findings encourage greater confidence in promoting this innovative thermomechanical-based healing treatment for in-situ surface course asphalt mixtures of road pavements.

scholarly journals Microwave Healing Performance of Asphalt Mixture Containing Electric Arc Furnace (EAF) Slag and Graphene Nanoplatelets (GNPs)

2020 ◽  
Vol 10 (4) ◽  
pp. 1428 ◽  
Author(s):  
Federico Gulisano ◽  
João Crucho ◽  
Juan Gallego ◽  
Luis Picado-Santos
Keyword(s):  
Microwave Heating ◽  
Healing Process ◽  
Asphalt Mixture ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Graphene Nanoplatelets ◽  
Asphalt Mixtures ◽  
Arc Furnace ◽  
Heating Efficiency ◽  
Eaf Slag

Pavement preventive maintenance is an important tool for extending the service life of the road pavements. Microwave heating seems to be a promising technology for this application, as bituminous materials have the potential to self-repair above a certain temperature. As ordinary asphalt mixture has low microwave absorbing properties, some additives should be used to improve the heating efficiency. In this paper, the effect of adding Electric Arc Furnace (EAF) slag and Graphene Nanoplatelets (GNPs) on the microwave heating and healing efficiency of asphalt mixtures was evaluated. Microwave heating efficiency was assessed by heating the specimens using several heating times. In addition, the electrical resistivity of the mixtures was measured to understand its possible relationship with the microwave heating process. Furthermore, the healing rates of the asphalt mixtures were assessed by repeated Indirect Tensile Strength (ITS) tests. The results obtained indicate that the additions of graphene and EAF slag can allow important savings, up to 50%, on the energy required to perform a good healing process.

Research of Mechanical Properties of Asphalt Pavement Materials with WMA and RAP

2012 ◽  
Vol 204-208 ◽  
pp. 3934-3937 ◽  
Author(s):  
Bao Yang Yu ◽  
Yu Wang ◽  
Min Jiang Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Dynamic Modulus ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Porous Asphalt ◽  
Compaction Energy ◽  
Indirect Tensile

The objectives of this paper are to characterize the mechanical properties of porous asphalt pavement mixtures containing RAP and a WMA additive using Super pave gyratory compactor and dynamic modulus testing. Four types of asphalt mixtures were evaluated in this study. This study evaluated compaction energy index, permeability, indirect tensile strength, and dynamic modulus for all types of porous asphalt mixtures. All of the asphalt mixtures meet the typical minimum coefficient of permeability in this study. In addition, only a slight decrease in was found when WMA additive was added to the porous asphalt mixture containing RAP. For indirect tensile strength testing, WMA containing RAP was found to have the highest tensile strength among all of the mixtures tested.

Experiment Study on Temperature Susceptibility of Cold Recycled Mix with Foamed Bitumen

2011 ◽  
Vol 374-377 ◽  
pp. 1627-1631
Author(s):  
Jin Zhi Xu ◽  
Pei Wen Hao
Keyword(s):  
Mechanical Properties ◽  
Asphalt Pavement ◽  
Compression Modulus ◽  
Recycled Asphalt ◽  
Tensile Strength Test ◽  
Bitumen Content ◽  
Indirect Tensile ◽  
Foamed Bitumen ◽  
Strength And Stiffness ◽  
Temperature Susceptibility

By using indirect tensile strength test and compression modulus test, the influences of variables, including recycled asphalt pavement (RAP) content and foamed bitumen content, on temperature susceptibility of mechanical properties of cold recycled mix with foamed bitumen (CRMFB) were studied. The results indicated that increase of RAP content had little impact on temperature susceptibility of CRMFB when small quantity of RAP (less than 70%) were contained, while enhanced temperature susceptibility of CRMFB was brought about when a large quantity of RAP (more than 70%) were contained. The mechanical properties, including strength and stiffness, manifested enhanced temperature susceptibility with the increase of foamed bitumen contents. Compared with HMA, CRMFB was obviously less susceptive to temperature.

scholarly journals Quantitative Analysis of the Blending Degree of Virgin and RAP Binders in Recycled Asphalt Mixtures with a High RAP Content

2018 ◽  
Vol 8 (12) ◽  
pp. 2668 ◽  
Author(s):  
Zhen Yang ◽  
Guoyi Zhuang ◽  
Xiaoshu Wei ◽  
Jintao Wei ◽  
Huayang Yu ◽  
...  
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Structural Index ◽  
Comprehensive Understanding ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt ◽  
Standard Curve ◽  
Study Results ◽  
Mineral Additives

Recycled asphalt mixtures (RAM), which are prepared by blending reclaimed asphalt pavement (RAP), virgin bitumen and mineral additives, provide a variety of advantages, including resource recycling, reductions in costs, and reduced negative environmental impacts. However, multiple agencies have expressed concerns about the utilization ratio of RAP; thus, a comprehensive understanding of the blending degree of virgin and RAP binders in RAM would be significantly helpful for promoting the application of RAP. This study aims to quantitatively analyze the blending degree of virgin and RAP binders in RAM with high RAP contents. Carboxyl-terminated butadiene acrylonitrile (CTBN) was utilized as a tracer to mark the virgin bitumen; in addition, Fourier transform infrared (FTIR) spectroscopy was used to develop the structural index of CTBN (ICTBN). By establishing the standard curve between ICTBN and the CTBN content, the blending degree of virgin and RAP binders at different locations within RAM can be determined quantitatively. The study results indicate that the RAP binder was completely blended with the virgin bitumen in the outer RAP layer. However, the blending degree decreased with an increase in the RAP depth, and the blending degree in the inner RAP layer was only approximately half that which was found in the case of complete blending.

scholarly journals Evaluation of Short-Term Aging Protocol for Asphalt Mixtures

2019 ◽  
Vol 9 (14) ◽  
pp. 2783 ◽  
Author(s):  
Sirin ◽  
Paul ◽  
Kassem ◽  
Ohiduzzaman
Keyword(s):  
Mechanical Properties ◽  
Asphalt Pavement ◽  
Road Construction ◽  
Asphalt Mixtures ◽  
Pavement Performance ◽  
Design Stage ◽  
Construction Site ◽  
Short Term ◽  
Compaction Processes

Asphalt mixtures are subjected to short-term aging during the production, placement, and compaction processes. Proper evaluation of asphalt pavement performance relies on the accurate characterization of asphalt mixtures during the design stage. In this study, three different loose asphalt mixtures often used in Qatar were evaluated to develop a laboratory short-term aging procedure. Sample mixtures 1 and 3 were collected from a construction site, while mixture 2 was obtained from an asphalt plant. Virgin aggregates and binders were also collected to reproduce the mixtures in the laboratory. Laboratory-produced mixtures were conditioned at 135 °C using various time durations. The mechanical properties of laboratory-produced mixtures were compared to those of mixtures produced on site. The results of the mechanical and binder testing demonstrated that the proper short-term aging protocol for asphalt mixtures often used in road construction in the State of Qatar would involve heating asphalt mixtures for 4 h at 135 °C before laboratory compaction.

scholarly journals Impact of Preheating Temperatures and RAP Characteristics on the Activation of RAP Binder

2020 ◽  
Vol 10 (23) ◽  
pp. 8378
Author(s):  
Yifu Meng ◽  
Liping Liu
Keyword(s):  
Mechanical Properties ◽  
Asphalt Pavement ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Central Plant ◽  
Preheating Temperature

Reclaimed asphalt pavement (RAP) is preheated to 120 °C or lower in hot central plant recycling due to specification and equipment limitations. However, the insufficient activation of reclaimed asphalt (RA) caused by low preheating temperature may affect the final properties of reclaimed asphalt mixtures (RAM) and lead to insufficient utilization of RA binder. This study evaluated the influence of preheating temperature and aging of RA binder on binder activation by producing specimens with 100% RAP. The volumetric and mechanical properties of specimens were analyzed to reflect the effect of activation. The results indicate that preheating temperature has a significant impact on the activation of RA binder. Regardless of the source of RAP, RA binder can be highly activated at 180 °C, while the degree of activation decreases significantly at 120 °C. By using an artificial RAP with different degrees of aging, the aging of RA binder is found to be harmful to activation only when the preheating temperature is low (such as 120 °C). Hence, if the equipment is capable of doing so, it is better to raise the preheating temperature of RAP to improve the activation of RA binder, especially for binder with a higher degree of aging.

Research on Electromagnetic Field Optimization for Microwave Hot Recycling of Asphalt Mixtures

2012 ◽  
Vol 462 ◽  
pp. 575-579 ◽  
Author(s):  
Tong Sheng Sun ◽  
Zhi Sheng Zhang ◽  
Ling Feng Tang
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Energy Distribution ◽  
Microwave Heating ◽  
Field Experiments ◽  
Heating System ◽  
Asphalt Mixtures ◽  
Electromagnetic Propagation ◽  
Recycled Asphalt ◽  
Electromagnetic Model

In order to investigate the law of electromagnetic propagation within microwave heating system, Maxwell's equations are applied to build electromagnetic model of recycled asphalt mixtures. Energy distribution of electromagnetic field in asphalt mixtures is researched based on the Poynting theory. The optimization model of electromagnetic field and structure are established by building relationship between electric field and magnetic field. Experiments of microwave heating allochroic silicagel are performed, which demonstrates the accuracy of electromagnetic field optimization.

scholarly journals Chemical Composition, pH Value, and Points of Zero Charge of High Calcium and High Iron Electric Arc Furnace Slag

2018 ◽  
Vol 7 (3.23) ◽  
pp. 1 ◽  
Author(s):  
Siti Zu Nurain Ahmad ◽  
Hamdan R ◽  
Wan Afnizan Wan Mohamed ◽  
N Othman ◽  
Nur Shaylinda Mohd Zin
Keyword(s):  
Chemical Composition ◽  
Calcium Oxide ◽  
Ferric Oxide ◽  
Ph Value ◽  
Steel Slag ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Arc Furnace ◽  
High Calcium ◽  
Eaf Slag

Electric arc furnace (EAF) slag as filter media has been extensively used nowadays for wastewater treatment technology. Steel slag was produced as byproduct from steelmaking processes. However, different batches of steel slag production produce different composition. Thus, this study determined the chemical composition, pH value and points of zero charge (PZC) of two different samples of electric arc furnace (EAF) slag; high iron EAF slag (Slag HFe) and high calcium EAF slag (Slag HCa). The steel slag were characterized using X-ray Fluorescence Spectroscopy (XRF) analysis for the chemical composition, extraction with boiling water for pH value, and salt addition method for PZC. Slag HFe was mainly consisted of 38.2% ferric oxide and 20.4% calcium oxide, 10.20 pH value and pH 10.55 for PZC. While for Slag HCa, they were composed of 1.64% ferric oxide and 49.5% calcium oxide of pH value of 11.11 and pH 11.75 for PZC. Therefore, Slag HCa was considered as a more basic species compared to Slag HFe. 

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