Degree Of Blending Research Articles

Quantifying the blending efficiency of warm mix asphalt-synchronous rejuvenated SBS-modified asphalt through a dynamic shear rheometer (DSR) testing approach

The degree of blending (DOB), which is controlled by the diffusion between virgin and aged/rejuvenated asphalt binder, has a major impact on the performance of the asphalt mixture incorporated with reclaimed asphalt pavement (RAP). Despite numerous studies investigating the DOB through experimental methods, the blending efficiency of warm mix asphalt (WMA) and synchronous rejuvenated SBS-modified asphalt (SBSMA) is still unexplored. In this study, a dynamic shear rheometer (DSR) testing approach was developed to quantify the blending efficiency of WMA modified SBSMA and synchronous rejuvenated SBSMA. The novelty of this approach lies in the innovative use of a DSR asphalt double-layer structure to determine the DOB in combination with a developed theoretical calculation framework. The individual and synergistic effects of WMA additive and rejuvenator type on the DOB of WMA modified SBSMA-Synchronous rejuvenated SBSMA were investigated, while the influence of blending temperature, blending time, and dosage of aged/rejuvenated SBSMA on the blending efficiency were systemically evaluated. Results indicated that the SBS repairing agent in the synchronous rejuvenator can dramatically increase the DOB, while the presence of WMA additive can further increase the DOB by improving the fluidity of the virgin SBSMA. Furthermore, increasing the blending temperature/blending time and decreasing the dosage of aged/rejuvenated SBSMA were also conducive to enhancing the DOB. In addition, a blending chart of the WMA modified SBSMA-Synchronous rejuvenated SBSMA was developed to facilitate the accurate prediction of the DOB at any given blending temperature and blending time.

Structural, optical analysis, stress-strain, and dielectric properties of selenium oxide/LaFeO3/blend nanocomposites with tunable properties for optoelectronics and micro-supercapacitors

This work focuses on developing flexible nanocomposites by introducing two types of ceramic nanofillers into a biopolymeric blend for optoelectronic and energy-storing applications. Selenium oxide (SeO2) nanoparticles (NPs) and LaFeO3 NPs were prepared by hydrothermal and solid-state reactions, respectively, and incorporated into the polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) through the solution casting process. Transmission electron microscope and X-ray diffraction tests revealed the creation of hexagonal SeO2 and orthorhombic LaFeO3 NPs, with average sizes of 17 and 93 nm. The blend's degree of crystallinity was dependent on SeO2 NPs and LaFeO3 contents. The infrared absorption spectra revealed the interactions/complexation of the fillers with the blend reactive groups. The scan e-microscope (field emission mode) investigated the films' surface morphology and detected the elements they contain. LaFeO3/SeO2 content impacted stress-strain behavior, raised the tensile strength from 64 to 70.9 MPa, and dramatically lowered the strain at break and toughness. UV–vis-NIR measurements exhibited that the transmittance, extinction coefficient, and refractive index can be tuned by SeO2 and LaFeO3/SeO2 content. The direct (Eg.d)/indirect (Eg.id) band gaps were reduced from 5.25/4.9 eV to 4.95/4.7 eV. The dielectric parameters (constant, loss, energy density, and conductivity) were significantly increased after loading 5.0 wt% LaFeO3/SeO2. The dielectric moduli and Cole-Cole plots were also investigated. The structural modifications and enhancement of the optical features and dielectric parameters make the resulted samples the best candidates for optoelectronic devices and energy-storing applications such as sensors and supercapacitors.

Tuning the band gap, optical, mechanical, and electrical features of a bio-blend by Cr2O3/V2O5 nanofillers for optoelectronics and energy applications

This work presents a facile approach for controlling the optical and electrical parameters of a biopolymeric matrix for optoelectronics. Vanadium oxide (V2O5) and chromium oxide (Cr2O3) nanoparticles (NPs) were prepared and incorporated into the carboxymethylcellulose/polyethylene glycol (CMC/PEG) blend by simple chemical techniques. Transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD) data showed that V2O5 and Cr2O3 exhibited spherical shapes with sizes in the range of 40–50 nm and 10–20 nm, respectively. In addition, the blend's degree of crystallinity was sensitive to the V2O5 and Cr2O3 doping ratios. The scanning electron microscopy (FE-SEM) and the elemental chemical analysis (EDAX) used to study the filler distribution inside the blend, and confirmed the existence of both V and Cr in the matrix. Fourier transform infrared (FTIR) spectroscopy showed that the dopants significantly affected the blend reactive (C–O–C, OH, and C=O) groups. The stress–strain curves illustrated the reinforcing effect of the dopants up to 1.0 wt\\%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext{wt\\%}$$\\end{document} Cr2O3/V. The transmittance and absorption index spectra in the visible-IR wavelengths decreased with increasing filler content. Utilizing Tauc's relation and (optical) dielectric loss, the direct (indirect) band gap narrowed from 5.6 (4.5) eV to 4.7 (3.05) eV at 1.0 wt\\%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext{wt\\%}$$\\end{document} Cr2O3/V. All films have an index of refraction in the range of 1.93–2.17. AC conductivity was improved with increasing filler content and temperature. The energy density at 50 °C is in the range of 1–3 J/m3. The influence of V2O5 and Cr2O3 content on the optical conductivity, dielectric constant, loss, and dielectric modulus of CMC/PEG was reported. These enhancements in electrical and optical properties, along with the potential for band gap engineering, offer promising prospects for advanced applications in optoelectronics and energy-related fields.

Analysis of the Degree of Blending (DoB) of recycled asphalt mixtures with variation in mixing temperature, type, and RAP content

Presently, there is a significant increase in studies dedicated to the reuse of Reclaimed Asphalt Pavement (RAP) material obtained from the recycling of asphalt coatings. This procedure aims to reduce production costs and minimize environmental impacts. To carry out the reuse of this material, it is crucial to understand the interaction mechanisms between the aged binder of the RAP and the new binder. These mechanisms can be assessed through the Degree of Binder Activity (DoA) and the Degree of Blending (DoB). DoA represents the quantity of aged binder available for the new mixture, being an intrinsic property of each RAP. On the other hand, DoB indicates the degree of blending between the aged and new binders, being influenced by external factors such as mixing parameters, thus presenting a challenge in quantification. This study sought to establish a predictive model to quantify DoB based on Dynamic Modulus and Fourier-Transform Infrared Spectroscopy (FTIR) tests. These tests were conducted on mixtures containing four different RAPs, varying in different content levels and mixing temperatures. In each RAP, DoA was quantified, and a statistical analysis was performed to verify the significance of independent variables in dynamic modulus results. After this step, four modeling attempts were made, choosing the one that not only presented significant independent variables but also obtained the highest predicted R² value. The chosen model was validated and demonstrated small variations compared to DoB obtained by the generated equation. Thus, it is concluded that the DoB modeling conducted in this study highlights that mixing temperatures and RAP content influence factors such as DoA, dynamic modulus, FTIR, and consequently, DoB. Additionally, the practicality of the model was emphasized, as it successfully predicted DoB using a single mechanical and chemical test.

Evaluation of degree of blending and its effect on performance of recycled hot-mix asphalt under different preheating conditions

This research comprehensively explored the function of preheating temperature and quantified the contribution of degree of blending (DoB) to performance of recycled hot-mix asphalt (HMAs). Five groups were designed, including no blending group, full blending group, and three experimental groups at preheating temperatures of 60, 110, and 160 °C. It can be found that the preheating temperature played a positive impact on DoB and performance of recycled HMAs. As the preheating temperature increased by 50 °C, about 0.13%–0.2% of reclaimed asphalt binder can be additionally activated, and the tensile strength ratio, shear strength, and fracture energy of recycled HMAs can improve by around 6%–8%, 0.07–0.15 MPa, and 304.2–335.4 J·m2, respectively. Moreover, the results showed that the performance of recycled mixes designed at preheating temperature of 60 °C was close to that of no blending group, while the mixes designed at a preheating temperature of 160 °C can reach to those of full blending group.

Effect of design parameters on degree of blending and performance of recycled hot-mix asphalt incorporating fine reclaimed asphalt pavement particles

Due to the rich binder content and high economic benefits of fine reclaimed asphalt pavement (RAP) particle, more and more attention has been paid to the effective design of recycled hot-mix asphalt (HMA) incorporating this material. This research explored the effect of design parameters on degree of blending (DoB) and performance of recycled HMAs incorporating fine RAP particles. Six groups of mixes were designed, including one no blending group, four experimental groups, and one full blending group. The different parameters of preheating temperature, compaction effort, asphalt content (AC), and blending duration, were involved in this research. It can be found that the recycled HMAs incorporating fine RAP particles under the traditional design proved to the risks in water stability and low-temperature performance. By rising the preheating temperature, decreasing compaction effort and increasing AC, or extending the blending duration, more RAP binder would be activated and blended with the virgin binder, and the poor rheological performance of recycled HMAs can be restored. The different design parameters have different effects on the performance. Besides, the actual contribution of DoB to performance was quantified. With an increase in DoB by 10%, the tensile strength ratio, shear strength, fracture energy, fracture strength, and abrasion loss percentage of recycled mixes can improve by around 15%∼28%, 0.15–0.34 MPa, 180–1969 J·m2, 0.25–0.34 MPa, and 7–18%, respectively. In addition, design incorporating fine RAP particles generally can bring significant advantages in energy consumption and CO2 emission.

Investigation on the influence of conditioning time on the performance of hot-recycled mixture under ambient temperature

Hot-recycled asphalt mixture (HRAM) has gained more attention due to its favorable performance and reuse of reclaimed asphalt pavement (RAP). However, involvement of the blending between virgin and aged asphalt may require more time to reach stability after the mixing process. It has been generally agreed that the change in degree of blending (DoB) between virgin and aged asphalt influences the performance of HRAM. Hence, it is of vital importance to reveal the development of the performances of HRAM in primary period and offer a reasonable conditioning time before conducting laboratory test to avoid over- or under-estimation. As many factors, including RAP content, aging degree of RAP and mixing procedure, may influence the conditioning time of HRAM, in this research, the HRAM with different RAP contents is taken into account. Specimens are stored at ambient environment (around 25 °C) for different days. Then, macroscopic performance tests evaluating high- and low-temperature performances as well as mechanical properties are conducted. Meanwhile, atomic force microscopy (AFM) is applied to quantify the change of nanoscale properties of HRAM under different conditioning time. The result shows that the macroscopic performances change significantly with conditioning time. But HRAM with different RAP contents exhibits distinct developing trend. Nevertheless, test results within 4 days varies significantly among all. AFM test reveals that DMT modulus increases with conditioning time, which is the reason for the performance change. Considering the time cost in laboratory testing, it is recommended for HRAM specimen to be conditioned at ambient temperature for at least 4 days before the tests. 7-day conditioning is better for HRAM with higher RAP content if time permits.

Effect of Blending Behavior on the Performance of Hot Recycled Asphalt Mixtures

Blending behavior is the main factor influencing hot recycled asphalt mixtures’ actual and design performance. The following steps were taken to investigate the above issues. Firstly, the component changes of asphalt mixtures were studied by thin-layer chromatography, with flame ionization detection to obtain the mechanism of asphalt aging and recycling. Secondly, according to the difference in the recycled asphalt components, the hot recycled asphalt mixtures were optimized based on the Marshall design method. Lastly, the hot recycled asphalt mixtures for the three mixing processes were prepared using the optimized design method described above. Laboratory tests were conducted to evaluate the correlation between the degree of blending (DoB) and the high-temperature stability, low-temperature crack resistance, water stability, and fatigue performance. The test results indicate that reducing light components (saturates and aromatics) and increasing heavy components (asphaltenes and resins) are the main reasons for asphalt aging, and asphalt recycling is an inverse process. Additionally, the performance of hot recycled asphalt mixtures is improved with an increase in DoB. Specifically, the DoB is only 50% to 60% under a normal mixing process, but by adjusting parameters the DoB will increase to 80% to 90%.

Effect of aging and blending duration on the degree of blending and performance of recycled hot-mix asphalt (HMA)

ABSTRACT This research explored the effect of aging and blending duration on the degree of blending (DoB) and performance of recycled HMAs, as well as the actual contribution of DoBs to the performance of recycled HMA. Nine groups were designed, including one group designed as “full blending group”; one group designed as “no blending group”; and seven experimental groups designed as “partial blending groups” under the different combinations of RAP materials and blending durations. The volumetric indicators, DoB, moisture susceptibility, high- and low-temperature performance of each group were assessed. It was found that prolonging the blending duration can effectively restore the performance of recycled HMAs containing RAP with serious aging. With the extension of blending duration by 180s, more RAP binder was activated, and the DoB of blended mixes enhanced by around 5%~30%, resulting in about 2%~16%, 8%~21%, and 7%~15% improved in the tensile strength ratio, shear strength, and fracture energy of recycled HMAs. In addition, the result also showed that about 10% increase in DoBs, corresponding to RAP binder activated by about 0.15% in this research, can contribute to around 1%~25%, 5%~16%, and 3%~24% improve in the water stability, high- and low-temperature performance of recycled HMAs, respectively.

Study on performance of recycled asphalt mixture based on blending state analysis of virgin and aged asphalt

ABSTRACT The blending state of virgin and aged asphalt is one of the key factors that influence the cracking resistance and fatigue performance of recycled asphalt mixtures. In this paper, the complex modulus of the virgin and aged double-layered asphalt samples was measured by DSR experiments, and the degree of blending (DOB) was calculated based on the complex modulus. The cracking resistance and fatigue performance of the mixture prepared under different blending conditions were tested and related to the DOB to obtain a prediction model. Results showed that the DOB and the complex modulus G* increased with blending time and temperature. The blending effect of modified asphalt was not as good as 70-pen asphalt. The contribution of blending time and temperature to DOB was 40% and 50%, respectively. The influence of DOB on cracking resistance and fatigue performance of recycled asphalt mixtures was consistent with DSR test. Good correlations between DOB, cracking resistance and fatigue performance were observed, which were 79.14% and 82.82%, respectively. Based on the DOB model, optimal blending temperature and blending time could be found according to the softening point difference between virgin and aged asphalt.

Study on Low-Temperature and Fatigue Performance of High RAP Content Hot Recycled Asphalt Mixture Based on the Degree of Blending (DOB).

This paper selected three kinds of AC-20 hot-mix recycled asphalt mixtures with high RAP content (30%, 40%, and 50%). It obtains a mixture of different degrees of miscibility by changing RAP preheating temperatures and mixing temperatures. The calculation formula of the degree of blending (DOB) of RAP asphalt interface recycling is proposed. The DSR test quantitatively characterized the DOB mixture's low temperature, and fatigue properties were tested by beam bending test and four-point bending fatigue test. The prediction models of the recycled mixture's low temperature and fatigue properties were proposed. The RAP preheating temperature is the most critical factor that dominates both transfers of RAP asphalt to the surface of new aggregate and the effective blending of old and new asphalt. DOB has a significant great influence on low-temperature performance and fatigue performance. The DOB of recycled asphalt can be improved by adjusting and optimizing the process parameters of plant hot recycled mixture to effectively improve the recycled mixture's low-temperature crack resistance and fatigue lifetime. The optimal RAP dosage and mixing process of required performance can be obtained based on the prediction models to save experimental time and cost.

A practical approach to estimate the degree of binder activity of reclaimed asphalt materials

Using Reclaimed Asphalt (RA) in new asphalt mixtures can reduce the amount of new material required thereby saving money and natural resources. In addition, asphalt mixtures with RA have shown comparable properties and performance to that generally associated with asphalt mixtures made with 100% virgin material. However, RA content in pavement surface layers is still limited due to specification and technical limitations. For higher contents, the aged RA binder must be analysed to accurately determine the requirements for virgin binders and additives while the degree of blending (DOB) between the RA binder and the virgin binder also needs to be quantified. This is not a simple process and generally designers assume one of two opposing theories associated with 100% (full blending) or 0% (“Black Rock”) DOB. This paper proposes a new approach to estimate a unique property of the RA known as the Degree of Binder Activity (DoA) as a function of the processing temperatures of the RA. The study showed positive results and indicated that this DoA approach can be used as a tool to better understand RA in order to improve the binder/blend design for recycled asphalt mixtures.

On the degree of binder activity of reclaimed asphalt and degree of blending with recycling agents

It is common practice to assume full blending of the aged binder of reclaimed asphalt (RA) within the design of new asphalt mixtures. Although being practical, this assumption has often led designers to asphalt mixtures lacking binder. Hence, going towards recycled asphalt mixtures (RAM) there is a need to have a better understanding of the blending phenomena, to have a general agreement on terminology and finally adapting RA classification and mix design procedures accordingly. This manuscript aims at being both a reference and stimulus for the scientific community to work in this direction and on this basis provides a nomenclature and a theoretical framework of the blending phenomena. The study is built upon a literature review on definitions, methods and influencing factors related with the blending phenomena and as a result, an intrinsic property of RA, the Degree of binder Activity (DoA), is introduced for the sake of improving RA classification. Furthermore, the two well-known concepts of the Degree of Blending (DoB) and the Degree of binder Availability (DoAv) are redefined, within the proposed framework, together with practical suggestions to introduce them in mix design procedures.

Determining the impact of degree of blending and quality of reclaimed asphalt pavement on predicted pavement performance using pavement ME design

Past studies indicated binder from reclaimed asphalt pavement (RAP) aggregates only partial degree of blending (DOB) within hot mix asphalt (HMA). Most state agencies assume full blending, which may lead to under asphalting. This study focuses on determining the impact of it on predicted performance using ME level I analysis of six 25% RAP mixes. Dynamic complex modulus (DCM) tests were conducted with full and “actual” blending, all greater than 85%, using varying conditions comparing rutting and fatigue performance. The results indicate high DOB RAP mixes with uniform gradations have negligible effect on predicted performance and would not compromise performance.