scholarly journals Mechanism of HCB-Modified Asphalt and Dynamic Properties of Mixtures

2020 ◽  
Vol 10 (14) ◽  
pp. 4971
Author(s):  
Zhan Ding ◽  
Jinfei Su ◽  
Peilong Li ◽  
Hui Bing
Keyword(s):  
Functional Groups ◽  
Oxygen Content ◽  
Performance Test ◽  
Dynamic Properties ◽  
Chemical Properties ◽  
Active Surface ◽  
Asphalt Mixtures ◽  
Low Frequencies ◽  
High Oxygen Content ◽  
Modified Asphalt

Hydroxymethyl carbon black (HCB) was prepared as an asphalt modifier with a high oxygen content and active surface chemical properties. The microstructure of HCB was analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. The improvement effect of HCB on asphalt’s physical, dynamic shear, rheological, and aging properties was evaluated. To analyze the dynamic properties of the HCB-modified asphalt mixtures, a simple performance test (SPT) was conducted, and then the change laws of the dynamic modulus and phase angle for the HCB mixtures were clarified. The results showed that the surface of HCB is smooth and that the oxygen content increases with the generation of hydroxyl functional groups. Polar oxygen-containing functional groups and hydrogen bonds are helpful in improving the resistance to cracking and aging. The surface activity of HCB is susceptible to temperature and frequency, causing a slight influence of HCB on the viscoelasticity of asphalt mixtures at high and low frequencies. At low temperatures and high frequencies, the HCB enhanced the elasticity characteristics and weakened the viscosity characteristics of asphalt mixtures.

scholarly journals Study on aging of lignin modified asphalt under thermogravimetric conditions

2021 ◽  
Vol 233 ◽  
pp. 01104
Author(s):  
Xin Fu ◽  
Mao He ◽  
Yuancai Liu
Keyword(s):  
Shear Modulus ◽  
Performance Test ◽  
Chemical Properties ◽  
Aging Effect ◽  
Complex Shear Modulus ◽  
Continuous Increase ◽  
Modified Asphalt ◽  
Complex Shear ◽  
And Performance ◽  
Different Content

In order to study the aging process of lignin-modified asphalt and explore the effect of lignin on the anti-aging performance of base asphalt, 4 sets of lignin-modified asphalt were prepared under different base asphalt, different dosage, temperature and time. Based on the thermal oxidation test (TFOT), dynamic shear rheological test (DSR), thermogravimetric test (TG), and infrared spectroscopy micro-performance test (FTIR), the high-temperature rheological properties and performance of aging lignin-based asphalt with different content were investigated. The changing law of the chemical properties of functional groups. The results show that the addition of lignin to the base asphalt sample increases the complex shear modulus G* and decreases the phase angle δ compared to the base asphalt sample prepared by the same sample preparation process. In the same sample, with the continuous increase of the test temperature, the complex shear modulus G* of the matrix asphalt before or after aging and the modified asphalt with different content of lignin showed a downward trend. The modification mechanism of lignin on asphalt is essentially that lignin decomposes and reacts with oxygen in the process of thermal oxidative aging, which delays the oxidation reaction of asphalt during aging, so as to achieve the anti-aging effect of asphalt.

Dynamic Modulus Characteristic of Large Stone Permeable Asphalt Mixtures

2013 ◽  
Vol 423-426 ◽  
pp. 1110-1113
Author(s):  
Jin Cheng Wei ◽  
Jin Li
Keyword(s):  
Phase Angle ◽  
Dynamic Modulus ◽  
Asphalt Mixtures ◽  
Sigmoidal Function ◽  
Master Curves ◽  
Low Frequencies ◽  
High Frequencies ◽  
Modified Asphalt ◽  
Large Stone ◽  
Dynamic Modulus Test

To study the dynamic modulus characteristic of LSPM mixes, dynamic modulus test was conducted for Large Stone Permeable Asphalt Mixtures (LSPM ) with neat asphalt and with modified asphalt and the range of dynamic modulus values for LSPM was determined and the dynamic modulus master curves were developed. The magnitude of the dynamic modulus decreased with an increase in temperature and increased with an increase in the frequency. The phase angle decreased as the frequency increased at low temperature. With temperature increase, there was a transition interval, where the phase angle increased up to frequencies of 0.5 Hz, and then it started to decrease as frequency increased. After the transition interval, the phase angle increased with an increase in frequency. Master curves developed by sigmoidal function showed that LSPM with modified asphalt exhibited higher dynamic modulus values at middle and high frequencies and lower dynamic modulus values at low frequencies.

scholarly journals Synthesis of High-Antifouling and Antibacterial Ultrafiltration Membranes incorporating Low Concentrations of Graphene Oxide

2020 ◽  
Author(s):  
Abedalkader Ibraheem Alkhouzaam ◽  
Hazim Qiblawey ◽  
Majeda Khraisheh
Keyword(s):  
Graphene Oxide ◽  
Oxygen Content ◽  
Pure Water ◽  
Antibacterial Properties ◽  
Chemical Properties ◽  
Industrial Applications ◽  
Oxidation Degree ◽  
High Oxygen Content ◽  
Antibacterial Performance ◽  
High Oxidation

Membrane treatment for wastewater treatment is one of the promising solutions to affordable clean water. It is a developing technology throughout the world and considered as the most effective and economical method available. However, the limitations of membranes’ mechanical and chemical properties restrict their industrial applications. Graphene Oxide (GO) is one of the materials that have been recently investigated in membrane water treatment sector. In this work, ultrafiltration polysulfone (PSF) membranes with high antifouling properties were synthesized by incorporating different loadings of GO. High-oxidation degree GO had been synthesized using modified Hummers’ method. The synthesized GO was characterized using different analytical techniques including (FTIR-UATR), Raman spectroscopy, and CHNSO elemental analysis that showed high oxidation degree of GO represented by the its oxygen content (50 wt.%). Morphology and hydrophilicity of membranes were investigated using SEM, AFM and contact angle analyses and showed clear effect of GO on PSF morphology and better hydrophilicity of GO-based membranes caused by the hydrophilic nature of GO and its high oxygen content. Separation properties of the prepared membranes were investigated using a cross-flow membrane system. Biofouling and organic fouling resistance of membranes were tested using bovine serum albumin (BSA) and humic acid (HA) as model foulants. It has been found that GO based membranes exhibit higher antifouling properties compared to pure PSF. When using BSA, the flux recovery ratio (FRR %) increased from 65.4 ± 0.9 % for pure PSF to 86.9 ± 0.1 % with loading of 0.1 wt.% GO in PSF. When using HA as model foulant, FRR increased from 87.8 ± 0.6 % to 95.6 ± 4.2 % with 0.1 wt.% of GO in PSF. The pure water permeability (PWP) decreased with loadings of GO from 181.7 L.m-2.h-1.bar-1 of pure PSF to 181.1 and 167.4 L.m-2.h-1.bar-1 with 0.02 and 0.1 wt.% GO respectively. Furthermore, GO based membranes exhibited effective antibacterial performance against Halomonas aquamarina compared to pristine PSF. It can be concluded from the obtained results that incorporating low loading of GO could enhance the antifouling and antibacterial properties of PSF hence improving its lifetime and reuse.

scholarly journals Mechanical Properties of Graphene Oxide Coupled by Multi-Physical Field: Grain Boundaries and Functional Groups

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Xu Xu ◽  
Zeping Zhang ◽  
Wenjuan Yao
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Grain Boundaries ◽  
Functional Groups ◽  
Oxygen Content ◽  
Tensile Fracture ◽  
Hydroxyl Groups ◽  
Molecular Configuration ◽  
Spatial Design ◽  
Out Of Plane

Graphene and graphene oxide (GO) usually have grain boundaries (GBs) in the process of synthesis and preparation. Here, we “attach” GBs into GO, a new molecular configuration i.e., polycrystalline graphene oxide (PGO) is proposed. This paper aims to provide an insight into the stability and mechanical properties of PGO by using the molecular dynamics method. For this purpose, the “bottom-up” multi-structure-spatial design performance of PGO and the physical mechanism associated with the spatial structure in mixed dimensions (combination of sp2 and sp3) were studied. Also, the effect of defect coupling (GBs and functional groups) on the mechanical properties was revealed. Our results demonstrate that the existence of the GBs reduces the mechanical properties of PGO and show an “induction” role during the tensile fracture process. The presence of functional groups converts in-plane sp2 carbon atoms into out-of-plane sp3 hybrid carbons, causing uneven stress distribution. Moreover, the mechanical characteristics of PGO are very sensitive to the oxygen content of functional groups, which decrease with the increase of oxygen content. The weakening degree of epoxy groups is slightly greater than that of hydroxyl groups. Finally, we find that the mechanical properties of PGO will fall to the lowest values due to the defect coupling amplification mechanism when the functional groups are distributed at GBs.

scholarly journals Evaluation of Properties and Micro-Characteristics of Waste Polyurethane/Styrene-Butadiene-Styrene Composite Modified Asphalt

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2249
Author(s):  
Bei Chen ◽  
Fuqiang Dong ◽  
Xin Yu ◽  
Changjiang Zheng
Keyword(s):  
Low Temperature ◽  
Performance Test ◽  
Permanent Deformation ◽  
Modified Asphalt ◽  
Basic Performance ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Sbs Modified Asphalt ◽  
And Storage ◽  
Butadiene Styrene

In order to solve the problems caused by asphalt diseases and prolong the life cycle of asphalt pavement, many studies on the properties of modified asphalt have been conducted, especially polyurethane (PU) modified asphalt. This study is to replace part of the styrene-butadiene-styrene (SBS) modifier with waste polyurethane (WP), for preparing WP/SBS composite modified asphalt, as well as exploring its properties and microstructure. On this basis, this paper studied the basic performance of WP/SBS composite modified asphalt with a conventional performance test, to analyze the high- and low-temperature rheological properties, permanent deformation resistance and storage stability of WP/SBS composite modified asphalt by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. The microstructure of WP/SBS composite modified asphalt was also observed by fluorescence microscope (FM) and Fourier transform infrared spectroscopy (FTIR), as well as the reaction between WP and asphalt. According to the results of this study, WP can replace SBS as a modifier to prepare WP/SBS composite modified asphalt with good low-temperature resistance, whose high-temperature performance will be lower than that of SBS modified asphalt. After comprehensive consideration, 4% SBS content and 15% WPU content (4 S/15 W) are determined as the suitable types of WPU/SBS composite modified asphalt.

scholarly journals Mechanical Characteristics of Graphene Nanoplatelets-Modified Asphalt Mixes: A Comparison with Polymer- and Not-Modified Asphalt Mixes

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2434
Author(s):  
Laura Moretti ◽  
Nico Fabrizi ◽  
Nicola Fiore ◽  
Antonio D’Andrea
Keyword(s):  
Fatigue Resistance ◽  
Graphene Nanoplatelets ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Asphalt Mixes ◽  
Modified Asphalt ◽  
Bituminous Mixtures ◽  
Water Sensitivity ◽  
Polymer Modified Asphalt ◽  
Mechanical Performances

In recent years, nanotechnology has sparked an interest in nanomodification of bituminous materials to increase the viscosity of asphalt binders and improves the rutting and fatigue resistance of asphalt mixtures. This paper presents the experimental results of laboratory tests on bituminous mixtures laid on a 1052 m-long test section built in Rome, Italy. Four asphalt mixtures for wearing and binder layer were considered: two polymer modified asphalt concretes (the former modified with the additive Superplast and the latter modified with styrene–butadiene–styrene), a “hard” graphene nanoplatelets (GNPs) modified asphalt concrete and a not-modified mixture. The indirect tensile strength, water sensitivity, stiffness modulus, and fatigue resistance of the mixtures were tested and compared. A statistical analysis based on the results has shown that the mixtures with GNPs have higher mechanical performances than the others: GNP could significantly improve the tested mechanical performances; further studies will be carried out to investigate its effect on rutting and skid resistance.

Investigation on the piezoresistive response of carbon fiber-graphite modified asphalt mixtures

2021 ◽  
Vol 301 ◽  
pp. 124140
Author(s):  
Liyuan Liu ◽  
Xiao Zhang ◽  
Lifei Xu ◽  
Hengji Zhang ◽  
Zhisheng Liu
Keyword(s):  
Carbon Fiber ◽  
Asphalt Mixtures ◽  
Modified Asphalt
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