Mechanical properties and reaction mechanism of microwave-activated crumb rubber-modified asphalt before and after thermal aging

2021 ◽  
Vol 267 ◽  
pp. 120773
Author(s):  
Lei Yin ◽  
Xiaolong Yang ◽  
Aiqin Shen ◽  
Hansong Wu ◽  
Zhenfeng Lyu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reaction Mechanism ◽  
Thermal Aging ◽  
Crumb Rubber ◽  
Modified Asphalt ◽  
Before And After

scholarly journals Influence of Mo Additions on the Mechanical Properties of Cast Duplex Stainless Steels before and after Thermal Aging

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 295
Author(s):  
Shilei Li ◽  
Yanli Wang ◽  
Xitao Wang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Thermal Aging ◽  
Decomposition Kinetics ◽  
Before And After ◽  
Mo Content ◽  
Impact Energies ◽  
The Impact ◽  
Hardness Values ◽  
Mo Additions

The influence of Mo additions on the mechanical properties of cast duplex stainless steel (CDSS) before and after thermal aging was investigated using a series of model alloys with different Mo contents ranging from 0 to 1.75 wt%. By increasing Mo content, the content, morphology, and distribution of ferrite in CDSS change significantly. After thermal aging at 400 °C for 3000 h, the impact properties of all CDSS specimens obviously decline, and their hardness values in ferrite significantly increase. The impact energies of the aged CDSS decline, and the proportion of cleavage features significantly increases with Mo content increasing. The spinodal decomposition kinetics in ferrite is not significantly affected by the Mo contents. High content and interconnected ferrite will lead to the severe embrittlement in CDSS after thermal aging.

scholarly journals The Effect of Activation Method of Rubber on the Performance of Modified Asphalt Binder

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3679
Author(s):  
Juan Xie ◽  
Yongning Zhang ◽  
Yueming Yang ◽  
Yunlong Ma ◽  
Jing Li ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Storage Stability ◽  
Rapid Development ◽  
Asphalt Binder ◽  
Polyamide 6 ◽  
Crumb Rubber ◽  
Activation Method ◽  
Modified Asphalt ◽  
Before And After ◽  
Modified Asphalt Binder

Poor storage stability is a key problem restricting the rapid development and wide application of rubber-modified asphalt binder, and activation of rubber has shown good prospects to solve this problem. In this study, two activation methods, coating by polyamide 6 and grafting by acrylamide, were introduced to treat crumb rubber. Then the activated rubber was added to base asphalt binder to prepare modified asphalt binder. The chemical structure and morphology of rubber powder before and after activation and of asphalt binder before and after modification were characterized by Fourier transformation infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The conventional and rheological properties and storage stability were analyzed to reveal the influence of activation method on the performance of asphalt binder. The results showed that after being activated, the surface of the rubber is loose and rough. A chemical reaction did not occur during activation by polyamide but occurred during activation by acrylamide. The activation of the rubber effectively improved the high- and low-temperature performance, and the softening difference decreased by 79.8%. This is because the interaction between rubber and asphalt binder was enhanced through activation of rubber, and grafting activation had better effect due to the chemical reaction between the basic amide groups of acrylamide and acid groups of asphalt binder.

scholarly journals Micro/Nanoscale Study on the Effect of Aging on the Performance of Crumb Rubber Modified Asphalt

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Lan Wang ◽  
Yang Liu ◽  
Le Zhang
Keyword(s):  
Molecular Dynamics ◽  
Crumb Rubber ◽  
Dynamics Simulation ◽  
Surface Microstructure ◽  
Test Results ◽  
Force Microscopy ◽  
Modified Asphalt ◽  
Atomic Force ◽  
Before And After ◽  
Microscopic Surface

In order to explore the variation of crumb rubber modified asphalt (CR) before and after aging at the micro- and nanoscales, the molecular dynamics simulation and atomic force microscopy (AFM) asphalt microstructure scanning were carried out on CR before and after aging. The molecular dynamics energy, radial distribution function (RDF), surface microstructure image, roughness, and other test results of the CR before and after aging were compared and analyzed. The results show that the molecular dynamic energy of the CR after aging increases; the asphaltene-asphaltene RDF is decreased after aging; and the AFM surface microstructure images of asphalt before and after aging do not change significantly, but quantitative analysis by roughness theory shows that aging makes the microscopic surface of the CR more uniform and gentle. By analyzing the changes of asphalt properties before and after aging at two scales, it can be found that there is a certain relationship between the properties obtained at different scales. The reasons and mechanisms for the influence of microstructure on aging are obtained by analyzing this relationship.

Research on Microstructure and Low Temperature Properties of Polymer Modified Asphalt

2015 ◽  
Vol 1094 ◽  
pp. 253-260
Author(s):  
Lan Wang ◽  
Yong Jie Jia ◽  
Lei Feng
Keyword(s):  
Low Temperature ◽  
Aging Effect ◽  
Crumb Rubber ◽  
Rubber Powder ◽  
Modified Asphalt ◽  
Macroscopic Structure ◽  
Before And After ◽  
Creep Stiffness ◽  
Distribution State ◽  
Polymer Modified Asphalt

In view of three kinds of polymer modified asphalt, Compound rubber powder modified asphalt, rubber powder modified asphalt and SBS modified asphalt, were commonly used in the Inner Mongolia region, scanning electron microscope (SEM) were used to observe the macroscopic structure morphology of asphalt before and after aging , getting the influence of aging effect on modifier’s distribution state in asphalt and interface combination properties between the asphalt, that is, after aging, three kinds of modifier and asphalt interface characteristic deterioration. By using bending beam rheometer (BBR) three kinds of asphalt after aging were conducted trabecular bending creep experiments under different temperature, through analyzing the changing rules of bending creep stiffness modulus S and the value of m, it can be get that: composite rubber powder modified asphalt has the best low temperature performance , followed by the crumb rubber modified asphalt.

Improvement in the mechanical properties of eutectic Sn58Bi alloy by 0.5 and 1 wt% Zn addition before and after thermal aging

2018 ◽  
Vol 765 ◽  
pp. 1243-1252 ◽  
Author(s):  
Shiqi Zhou ◽  
Omid Mokhtari ◽  
Muhammad Ghufran Rafique ◽  
Vasanth C. Shunmugasamy ◽  
Bilal Mansoor ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Aging ◽  
Zn Addition ◽  
Before And After

scholarly journals Aging Properties and Mechanism of Microwave-Activated Crumb Rubber Modified Asphalt Binder

2020 ◽  
Vol 7 ◽  
Author(s):  
Tao Zhou ◽  
Jianing Zhou ◽  
Qidong Li ◽  
Bo Li
Keyword(s):  
Functional Group ◽  
Asphalt Binder ◽  
Molecular Size ◽  
Gel Permeation Chromatography ◽  
Aging Effect ◽  
Microwave Treatment ◽  
Crumb Rubber ◽  
Microwave Activation ◽  
Modified Asphalt ◽  
Before And After

Although crumb rubber modified asphalt (CRMA) has a better performance than matrix asphalt (MA) in road engineering, the application bottlenecks of this material lies in its high viscosity, poor workability and bad storage stability. Microwave technology is one of the solutions to the above problems. The objective of this study was to investigate the physical and chemical changes before and after aging of CRMA which was prepared by microwave activated crumb rubber, and the aging mechanism of microwave-activated crumb rubber modified asphalt (MACRMA). Through penetration, softening point, ductility, viscosity and DSR test, the high and low temperature performance and temperature sensitivity of MA, CRMA and MACRMA before and after aging were studied. These tests results revealed that microwave treatment can improve the anti-rutting ability and the anti-aging performance of rubber asphalt. According to gel permeation chromatography (GPC) test, the distribution changes of the internal molecular content of the three asphalts were determined during the aging process. Its test results showed that aging effect accelerated the conversion of small molecules to large molecules in asphalt, and the value of large molecular size (LMS) increases more after long-term aging. The microwave activation made the swelling reaction more intense, thereby delayed the conversion of LMS in the rubber asphalt. In addition, LMS has a high correlation with test indicators. The fourier transform infrared spectroscopy (FTIR) test was used to measure the functional group changes of each asphalt. The FTIR spectra indicated that microwave activation is mainly a process of physical change. The carbonyl and sulfoxide functional group indices of MACRMA were lower than those of MA and CRMA, which also confirmed that MACRMA has a better anti-aging ability.

scholarly journals The influence of carbon black on curing kinetics and thermal aging of acrylonitrile-butadiene rubber

2009 ◽  
Vol 15 (4) ◽  
pp. 283-289 ◽  
Author(s):  
Vojislav Jovanovic ◽  
Jaroslava Budinski-Simendic ◽  
Suzana Samardzija-Jovanovic ◽  
Gordana Markovic ◽  
Milena Marinovic-Cincovic
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Thermal Aging ◽  
Network Formation ◽  
Curing Kinetics ◽  
Hydraulic Press ◽  
Butadiene Rubber ◽  
Aging Properties ◽  
Before And After ◽  
Elastomeric Materials

Elastomers based on a copolymer of butadiene and acrylonitrile (NBR) have excellent oil resistance but are very sensitive for degradation at very high temperatures. The aim of this applicative contribution was to determine the effect of high abrasion furnace carbon black with primary particle size 46 nm on aging properties of elastomeric materials based on NBR as network precursor. The curing kinetics was determined using the rheometer with an oscillating disk, in which the network formation process is registered by the torque variation during time. The vulcanizates were obtained in a hydraulic press at 150?C. The mechanical properties of elastomeric composites were determined before and after thermal aging in an air circulating oven. The reinforcing effect of the filler particles was assessed according to mechanical properties before and after aging.

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

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