scholarly journals Study on Storage Stability of Activated Reclaimed Rubber Powder Modified Asphalt

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4684
Author(s):  
Peipei Kong ◽  
Gang Xu ◽  
Jingyao Yang ◽  
Xianhua Chen ◽  
Yaqin Zhu
Keyword(s):  
Storage Stability ◽  
Waste Recycling ◽  
Short Term ◽  
One Pot ◽  
Dual Purpose ◽  
Rubber Powder ◽  
Modified Asphalt ◽  
Solid Waste Recycling ◽  
By Products ◽  
Modify Asphalt

The purpose of this research was to make full use of waste lubricating by-products (LBP) and reclaimed rubber powder (RR) to modify asphalt by a one-pot approach, so as to achieve the dual purpose of solving the poor storage stability of reclaimed rubber powder modified asphalt (RRMA) and the realization of solid waste recycling. A variety of characterization techniques were performed to analyze storage stability, conventional properties and microstructure of LBP-activated reclaimed rubber powder modified asphalt (Blend). Fourier transform infrared spectroscopy illustrated that not only the chemical composition of LBP was very similar to that of asphalt, but also the activation of LBP improved the compatibility of RR with asphalt and enhanced the storage stability of Blend. Fluorescence spectrum and scanning electron microscopy results indicated that the RR without LBP activation was aggregated and dispersed as blocks in asphalt, while the LBP activated RR was uniformly dispersed in the asphalt phase. The segregation test demonstrated that Blend exhibited outstanding storage stability, in which the softening point difference was within 2.5 °C and the segregation rate was −0.2–0.2. In addition, the conventional properties of Blend have been significantly improved, especially in penetration and ductility. More importantly, the short-term aging results demonstrated that, compared with RRMA, Blend possessed excellent anti-aging performance.

scholarly journals Investigation on the Short-Term Aging-Resistance of Thermoplastic Polyurethane-Modified Asphalt Binders

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1189 ◽  
Author(s):  
Ruien Yu ◽  
Xijing Zhu ◽  
Maorong Zhang ◽  
Changqing Fang
Keyword(s):  
Thermal Properties ◽  
High Temperature ◽  
High Speed ◽  
Storage Stability ◽  
Thermoplastic Polyurethane ◽  
Short Term ◽  
Modified Asphalt ◽  
Aging Resistance ◽  
High Temperature Storage ◽  
Temperature Storage

In this reported work, thermoplastic polyurethane (TPU) was used as a reactive polymer modifying agent to prepare a modified-asphalt, using a high-speed shearing method. Physical performance tests of the TPU-modified asphalt were conducted before and after short-term aging, and the aging resistance was examined by the change in materials properties. In addition, low-temperature rheological properties, thermal properties, the high-temperature storage stability, and the aging mechanism of TPU-modified asphalt were also investigated. The results showed that the addition of TPU improved the aging resistance of base asphalt, which was evidenced by the increased penetration ratio and decreased softening point of the asphalt, after aging. Similarly, Fourier Transform infrared (FTIR) spectroscopy results verified that TPU improved the asphalt aging resistance. It was found that the TPU functional groups played a role in improving thermal properties, high-temperature storage stability, and in the dispersion of modified asphalt.

scholarly journals Enhanced Storage Stability and Rheological Properties of Asphalt Modified by Activated Waste Rubber Powder

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2693
Author(s):  
Weihong Liu ◽  
Yishen Xu ◽  
Hongjun Wang ◽  
Benan Shu ◽  
Diego Maria Barbieri ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Large Scale ◽  
Storage Stability ◽  
Chemical Activation ◽  
Crumb Rubber ◽  
Rubber Powder ◽  
Modified Asphalt ◽  
Waste Rubber ◽  
Waste Rubber Powder ◽  
Physical And Chemical

Segregation of waste crumb rubber powder (WR) modified asphalt binders the large-scale application of WR in asphalt. The method of microwave activation combined with chemical activation (KMWR) was proposed to improve storage stability and rheological properties of WR modified asphalt in this work. Storage stability and rheological properties of virgin asphalt, MWR modified asphalt, and KMWR modified asphalt were comparatively studied by the standard segregation test, bending beam rheometer (BBR) test, and dynamic shear rheometer (DSR) test. The effect of composite activation on waste rubber powder particles was studied by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and Brunauer–Emmett–Teller (BET) tests. The main results showed that after the physical and chemical composite activation, the storage stability of waste rubber powder modified asphalt was significantly improved, WR modified asphalt had better crack resistance, better rutting resistance, and better fatigue performance. After physical and chemical activation, WR was desulfurized, and a large number of active groups was grafted on the WR particles.

Evaluation of Stability, Nature of Modifier, and Short-Term Aging of Modified Binders Using New Tests: LAST, PAT, and Modified RTFO

1998 ◽  
Vol 1638 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Hussain U. Bahia ◽  
Huachun Zhai ◽  
Andres Rangel
Keyword(s):  
Storage Stability ◽  
Data Interpretation ◽  
Test Methods ◽  
Asphalt Binders ◽  
Short Term ◽  
Testing Procedures ◽  
Modified Asphalt ◽  
Typical Data ◽  
Modified Binders ◽  
Modified Binder

In a recent survey of users and producers of modified asphalts, stability and short-term aging were two of the main concerns regarding the use of modified asphalts. In an NCHRP project, a concentrated effort was put into development of revised or new testing procedures to better characterize the nature of modified asphalt and to solve some of the difficulties with using existing aging procedures developed for neat asphalts and modified asphalts. Three main procedures have been proposed to complement the existing Superpave procedures: the laboratory asphalt stability test, for measuring the storage stability of asphalt binders; the particulate additive test, for separation of particulate additives; and the modified rolling thin film oven test for short-term aging. The background behind the development of these test methods is explained, and typical data collected for a number of modified asphalts are presented. The results indicate that these tests show high promise in covering characteristics not covered by the current Superpave binder specifications and in solving some of the problems with the existing aging methods. The results also indicate that the behavior of modified binder can be very complex and that the method of data interpretation is very critical.

scholarly journals Rheological Characteristics of Tire Rubber-Modified Asphalt following Thermal Variation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
S. Chen ◽  
J. Cao ◽  
C. f. Zheng ◽  
X. D. Guo
Keyword(s):  
Low Temperature ◽  
Automobile Industry ◽  
Urgent Problem ◽  
Thermal Variation ◽  
Rubber Powder ◽  
Waste Tires ◽  
Modified Asphalt ◽  
Temperature Shear ◽  
Powder Content ◽  
Modify Asphalt

In recent years, due to the development of the automobile industry, there are more and more waste car tires, and the reuse of waste tires has become an urgent problem to be solved. In this study, the crushed rubber of waste automobile tires is used to modify asphalt to prepare rubber-modified asphalt, which can not only solve the problem of using waste tires but also effectively improve the performance of asphalt pavement. This study defines four modified asphalts with different rubber powder content, which are defined as 1#, 2#, 3#, and 4#, respectively. The performance difference between the four modified asphalts and the base asphalt was compared through experiments to illustrate the advantages of rubber-modified asphalt. The four selected rubber asphalts and base asphalt are subjected to the viscous toughness test, apparent viscosity test, DSR test, and BBR test to determine the high- and low-temperature characteristics of rubber asphalt. The analysis of experimental data shows that rubber-modified asphalt can effectively improve the low-temperature performance of the asphalt, make the asphalt have better toughness, and also improve the high-temperature shear resistance of the asphalt. Finally, it is determined that adding 10% rubber powder to the base asphalt has the best effect.

scholarly journals Research on the Viscosity-Temperature Properties and Thermal Stability of Stabilized Rubber Powder Modified Asphalt

2021 ◽  
Vol 13 (24) ◽  
pp. 13536
Author(s):  
Qingwei Ma ◽  
Zhongyin Guo ◽  
Ping Guo ◽  
Fayong Yang ◽  
Haibin Li
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Storage Stability ◽  
Thermal Storage ◽  
Rubber Powder ◽  
Modified Asphalt ◽  
Differential Scanning Calorimeters ◽  
The Impact ◽  
Scanning Electron

A stabilized rubber powder-modified asphalt was provided for the field of rubber asphalt, and the optimal blending amount of stable rubber powder was determined from indicators, such as penetration, penetration index, ductility, softening point, and viscosity at 135 °C. The viscoelastic curve was measured, and the thermal storage stability test showed that the stabilized rubber powder-modified asphalt has significant thermal storage stability. The specific surface area, scanning electron microscope, and differential scanning calorimeters were used to analyze the dispersion state and aggregation state of the rubber powder particles in the stabilized rubber powder-modified asphalt, etc. The swelling state and reaction mechanism of the rubber powder in the stabilized rubber powder-modified asphalt have been characterized. The results show that the temperature sensitivity of the asphalt was improved after the stabilized rubber powder was added. The content of the stabilized rubber powder was determined to be 30%, which effectively reduces the viscosity at 135 °C, and the workability is improved; the impact of rubber powder-modified asphalt was less than that of ordinary rubber asphalt, but the temperature should be strictly controlled to ensure the viscosity of stable rubber powder-modified asphalt; the specific surface area comparison test shows that the stable rubber powder has better performance than ordinary rubber powder and asphalt matrix. The advantage of having a larger contact area enhances the compatibility of stabilized rubber powder with asphalt; scanning electron microscopy and differential scanning calorimeters test results show that the stable rubber powder-modified asphalt is mainly based on the compatibility mechanism, and a series of processes, such as oil absorption swelling-high temperature shear-compatible dispersion, occur.

scholarly journals Greener Solution to Waste Corn Stalks and Shortage of Asphalt Resource: Hydrochar Produced by Hydrothermal Carbonization as a Novel Performance Enhancer for Asphalt Binder

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1427
Author(s):  
Xiaoming Wu ◽  
Chichun Hu
Keyword(s):  
High Temperature ◽  
Reaction Temperature ◽  
Storage Stability ◽  
Asphalt Binder ◽  
Aging Effect ◽  
Experimental Tests ◽  
Hydrothermal Carbonization ◽  
Modified Asphalt ◽  
Direct Combustion ◽  
Aging Property

Utilization of waste corn stalks (CS) has seized extensive attention due to high annual output and hazardous impact of piling aside or direct combustion on environment. However, previously there has been a lot of emphasis on improvement of its energy efficiency as solid fuel while limited investigations are available which explore the possibility of applying corn stalks as performance enhancer in asphalt binder. The purpose of this study is to examine the potential of employing hydrochar as modifiers in asphalt binder by a series of experimental tests. In this study, two hydrochar were produced from corn stalks by a novel process called hydrothermal carbonization at a different reaction temperature. The two hydrochar and their responding hydrochar-modified asphalt (HCMA) were tested by chemical and rheological tests. Chemical analysis detected the interaction between hydrochar and binder factions, resulting in poor compatibility but satisfying anti-aging property. Even though hydrochar increased the viscosity of bitumen, implying worse workability, and caused poor storage stability, ameliorated performance of asphalt binder at high temperature by incorporating hydrochar was verified by various criteria such as higher performance grade (PG) failure temperature and lower non-recoverable creep compliance (Jnr). Moreover, higher reaction temperature makes hydrochar’s particles smaller and more homogeneous, which results in slightly lower enhanced high temperature performance, more satisfying workability, better storage stability, and greater anti-aging effect of hydrochar-modified asphalt. Eventually, this study provided a promising win-win solution to environment problems concerning corn stalk treatment and shortage of asphalt binder. Further exploration of methods to improve HCMA’s storage stability, real-scale corroboration on trial section and life cycle assessment of asphalt pavement containing hydrochar modifiers will be followed in the future.

scholarly journals Asphalt Incorporation with Ethylene Vinyl Acetate (EVA) Copolymer and Natural Rubber (NR) Thermoplastic Vulcanizates (TPVs): Effects of TPV Gel Content on Physical and Rheological Properties

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1397
Author(s):  
Nappaphan Kunanusont ◽  
Boonchai Sangpetngam ◽  
Anongnat Somwangthanaroj
Keyword(s):  
Storage Stability ◽  
Ethylene Vinyl Acetate ◽  
Softening Temperature ◽  
Plastic Waste ◽  
Gel Content ◽  
Modified Asphalt ◽  
C Storage ◽  
Thermoplastic Vulcanizates ◽  
Polymer Modified Asphalt ◽  
And Storage

Plastic waste has been incorporated with asphalt to improve the physical properties of asphalt and alleviate the increasing trend of plastic waste being introduced into the environment. However, plastic waste comes in different types such as thermoplastic or thermoset, which results in varied properties of polymer modified asphalt (PMA). In this work, four thermoplastic vulcanizates (TPVs) were prepared using different peroxide concentrations to produce four formulations of gel content (with varying extent of crosslinked part) in order to imitate the variation of plastic waste. All four TPVs were then mixed with asphalt at 5 wt% thus producing four formulations of PMA, which went through physical, rheological, and storage stability assessments. PMA with higher gel content possessed lower penetration and higher softening temperature, indicating physically harder appearance of PMA. Superpave parameters remained unchanged among different gel content PMA at temperatures of 64, 70, and 76 °C. PMA with any level of gel content had lower Brookfield viscosity than PMA without gel content at a temperature of 135 °C. Higher gel content resulted in shorter storage stability measured with greater different softening temperatures between top and bottom layers of PMA after 5 days of 163 °C storage. This study shows that asphalt with thermoset plastic waste is harder and easier to pave, thus making the non-recycling thermoset plastic waste more useful and friendly to the environment.

scholarly journals Cascading Old Yellow Enzyme, Alcohol Dehydrogenase and Glucose Dehydrogenase for Selective Reduction of (E/Z)-Citral to (S)-Citronellol

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 931
Author(s):  
Yunpeng Jia ◽  
Qizhou Wang ◽  
Jingjing Qiao ◽  
Binbin Feng ◽  
Xueting Zhou ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Glucose Dehydrogenase ◽  
Selective Reduction ◽  
Coli Strain ◽  
Severe Reaction ◽  
High Catalytic Activity ◽  
Old Yellow Enzyme ◽  
One Pot ◽  
Nadph Regeneration ◽  
By Products

Citronellol is a kind of unsaturated alcohol with rose-like smell and its (S)-enantiomer serves as an important intermediate for organic synthesis of (-)-cis-rose oxide. Chemical methods are commonly used for the synthesis of citronellol and its (S)-enantiomer, which suffers from severe reaction conditions and poor selectivity. Here, the first one-pot double reduction of (E/Z)-citral to (S)-citronellol was achieved in a multi-enzymatic cascade system: N-ethylmaleimide reductase from Providencia stuartii (NemR-PS) was selected to catalyze the selective reduction of (E/Z)-citral to (S)-citronellal, alcohol dehydrogenase from Yokenella sp. WZY002 (YsADH) performed the further reduction of (S)-citronellal to (S)-citronellol, meanwhile a variant of glucose dehydrogenase from Bacillus megaterium (BmGDHM6), together with glucose, drove efficient NADPH regeneration. The Escherichia coli strain co-expressing NemR-PS, YsADH, and BmGDHM6 was successfully constructed and used as the whole-cell catalyst. Various factors were investigated for achieving high conversion and reducing the accumulation of the intermediate (S)-citronellal and by-products. 0.4 mM NADP+ was essential for maintaining high catalytic activity, while the feeding of the cells expressing BmGDHM6 effectively eliminated the intermediate and by-products and shortened the reaction time. Under optimized conditions, the bio-transformation of 400 mM citral caused nearly complete conversion (>99.5%) to enantio-pure (S)-citronellol within 36 h, demonstrating promise for industrial application.

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