scholarly journals Identifying the Long-Term Thermal Storage Stability of SBS-Polymer-Modified Asphalt, including Physical Indexes, Rheological Properties, and Micro-Structures Characteristics

2021 ◽  
Vol 13 (19) ◽  
pp. 10582
Author(s):  
Peng Wang ◽  
Hong-Rui Wei ◽  
Xi-Yin Liu ◽  
Rui-Bo Ren ◽  
Li-Zhi Wang

The thermal storage stability of styrene–butadiene–styrene tri-block copolymer modified bitumen (SBSPMB) is the key to avoid performance attenuation during storage and transportation in pavement engineering. However, existing evaluation index softening point difference within 48 h (ΔSP48) cannot effectively distinguish this attenuation of SBSPMB. Thus, conventional physical indexes, rheological properties, and micro-structure characteristics of SBSPMB during a 10-day storage were investigated in this research. Results showed that during long-term thermal storage under 163 °C for 10 days, penetration, ductility, softening point, recovery rate (R%), and anti-rutting factor (G*/sinδ) were decayed with storage time increasing. This outcome was ascribed to the phase separation of SBS, which mainly occurred after a 4-day storage. However, ΔSP48 after a 6-day storage met the specification requirements (i.e., below 2.5 °C). Thus, the attenuation degree of asphalt performance in field storage was not effectively characterized by ΔSP48 alone. Results from network strength (I) and SBS swelling degree tests revealed that the primary cause was SBS degradation and base asphalt aging. Moreover, conventional indexes, including penetration, ductility, and softening point, were used to build a prediction model for rheological properties after long-term storage using partial least squares regression model, which can effectively predict I, R, Jnr, G*/sinδ, and SBS amount. Correlation coefficient is above 0.8. G*/sinδ and I at the top and bottom storage locations had high coefficient with SBS amount. Thus, phase separation of SBSPMB should be evaluated during thermal storage.

Bitumen modification is done to enhance the properties of bitumen related to elasticity, temperature susceptibility, softening point etc. This research intends to assess the effects of natural rubber latex (NRL) in liquid form as a bitumen modifier. Conventional tests, temperature susceptibility and phase separation due to hot storage were investigated using two separate mixing speeds of 1200 and 1300 revolution per minutes (rev/min). Morphology due to the addition of NRL has also been explored utilizing Atomic Force Microscopy (AFM). NRL was incorporated into the bitumen by weight of the binder for the modification at three different amounts (i.e. 3%, 5% and 6%). Based on the softening point, penetration value, temperature susceptibility and storage stability the latex-modified asphalt binder were analyzed. Results of the investigation showed that owing to enhancement in viscoelastic properties, the latex-modified asphalt binder will not undergo phase separation during hot temperature storage. Meanwhile, a uniform dispersed network was indicated by the morphological analysis with the presence of three phases of para, peri and cata. It can be deduced from the results obtained that the latex-modified asphalt binders will perform better in terms of softening point, penetration value and susceptibility due to temperature.


ACS Omega ◽  
2020 ◽  
Vol 5 (42) ◽  
pp. 27171-27179 ◽  
Author(s):  
Indika K. Warnakula ◽  
Afshin Ebrahimpour ◽  
Sun Yi Li ◽  
Ramesha D. Gaspe Ralalage ◽  
Chathuranga C. Hewa-Rahinduwage ◽  
...  

2018 ◽  
Vol 80 (4) ◽  
Author(s):  
Ebenezer Akin Oluwasola ◽  
Mohd Rosli Hainin ◽  
Mohd Khairul Idham ◽  
Modupe Abayomi

The failures of the flexible pavements are not only caused by harsh climatic conditions prevailing in most of the tropical countries but also due to increase in traffic. The ethylene vinyl acetate (EVA) modification of the bitumen can strengthen the properties of binders and also improve the quality of bitumen used for pavements construction. This paper reports the changes in physical and rheological properties of unaged 80-100 grade bitumen modified with different percentages of EVA and compared with the properties of PG 76 binder. The penetration, softening point and viscosity properties were studied. The rheological properties were measured using dynamic shear rheometer and the test was performed at temperatures ranging from 46 to 76 ⁰C at intervals of 6 ⁰C. It was noted that, after modification, the properties of binders had improved. The results show that 5% EVA content by weight in modified binder is adequate in terms of physical and rheological properties studied. In addition, the properties of 5% EVA modified 80-100 grade bitumen are similar to PG 76 binder.


2004 ◽  
Vol 93 (10) ◽  
pp. 2609-2623 ◽  
Author(s):  
Derrick S. Katayama ◽  
Carol F. Kirchhoff ◽  
Carrie M. Elliott ◽  
Robert E. Johnson ◽  
Jeffry Borgmeyer ◽  
...  

2018 ◽  
Vol 1 (5) ◽  
pp. 2184-2194 ◽  
Author(s):  
Jie Feng ◽  
Yingyue Zhang ◽  
Simon A. McManus ◽  
Kurt D. Ristroph ◽  
Hoang D. Lu ◽  
...  

Energy ◽  
2019 ◽  
Vol 186 ◽  
pp. 115882 ◽  
Author(s):  
Wenfei Cai ◽  
Ning Kang ◽  
Moon Ki Jang ◽  
Chen Sun ◽  
Ronghou Liu ◽  
...  

1996 ◽  
Vol 59 (5) ◽  
pp. 481-486 ◽  
Author(s):  
HSING-YI HSIEH ◽  
BONITA A. GLATZ

Propionicin PLG-1, a bacteriocin produced by Propionibacterium thoenii strain P127, was tested for characteristics that could determine its usefulness as a food preservative: long-term storage stability and effectiveness in a food model system. Partially purified propionicin PLG-1 samples, lyophilized and nonlyophilized, were stored at 25, 4, and −20°C. Bacteriocin activity increased by as much as 200% over the first 10 days of storage in nonlyophilized samples stored at 25 or 4°C. Activity then decreased gradually for samples stored at 25°C while samples stored at 4°C retained high activity through 14 weeks of storage. Nonlyophilized samples frozen at −20°C and lyophilized samples stored at all temperatures did not change significantly in activity through 25 weeks of storage. Propionicin was added at 100 and 1,000 arbitrary units (AU)/ml to lactobacilli MRS broth and to skim milk, each inoculated with 105 cells per ml of Lactobacillus delbrueckii ATCC 4797. Upon incubation at 37°C with 1,000 AU/ml, cell numbers were reduced by at least 4 log units within 2 h and no viable cells were detected after 96 h in either medium. With 100 AU/ml of propionicin, viable cells were reduced by 2 log units within 12 h at 37°C, but culture growth resumed after 24 h. At 15°C, no viable cells were detected after 48 h in the presence of 1,000 AU/ml of propionicin, while viable cell counts were gradually reduced to about 10 cells per ml by 168 h in the presence of 100 AU/ml of propionicin.


2017 ◽  
Vol 79 (6) ◽  
Author(s):  
Nura Bala ◽  
Ibrahim Kamaruddin ◽  
Madzlan Napiah

Polymer modified bitumen (PMB) has been used for many years to improve the performance of asphalt concretes against premature pavement defects. In this research, modified samples were prepared with 2%, 3%, 4%, 5% and 6% Linear Low Density Polyethylene (LLDPE) polymer by weight of bitumen binder. The influence of LLDPE polymer was evaluated through binder properties test which includes penetration, softening point, storage stability, temperature susceptibility, rutting, fatigue and thermal oxidative aging resistance from a dynamic shear rheometer (DSR) measurements at a temperature of 20 OC to 60 OC. Results show that LLDPE polymer has a significant effect on binder properties. Penetration decreases and softening point increases with increasing LLDPE content on the modified binder after aging, which implies LLDPE improves the thermo oxidative aging resistance of the binder. Furthermore, the storage stability test shows that at higher LLDPE concentrations phase separation may occur. DSR analysis shows that modified binders have lower temperature susceptibility and higher aging resistance with increased stiffness and elastic behavior compared with unmodified binders. In addition, modified binders show enhanced resistance against high temperature rutting and at low temperature fatigue performance. It was found that the optimum LLDPE content is 6%.


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