scholarly journals Role of Aliphatic Chain Characteristics on the Anti-Cracking Properties of Polymer-Modified Asphalt at Low Temperatures

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2025 ◽  
Author(s):  
Peng Wang ◽  
Fu-quan Shi ◽  
Xi-yin Liu ◽  
Rui-bo Ren ◽  
Ying Zhu ◽  
...  

The anti-cracking properties of polymer-modified asphalt depend largely on the molecular structure of the polymer modifier. However, the mysterious structure-performance relationship is still elusive. In this paper, three kinds of polymers with different chain structures were selected to address this issue. The indices of styrene, trans-butadiene, aliphatic branched-chain, and aliphatic long-chain from the infrared spectrum were used to quantify the functional group compositions of polymer modifiers. Viscoelastic parameters, including relaxation time, dissipation energy ratios, and stiffness were assessed to illustrate the anti-cracking properties of polymer-modified asphalt. Results showed that relaxation time and dissipation energy ratios were mainly determined by the polymer network strength, molecular size, aliphatic chain feature, and the orientations speed of aliphatic chains. The short relaxation time and high dissipation ratio lead to the low stiffness and favorable low-temperature performance of asphalt. The improvement of these performances requires a polymer with high indices of an aliphatic long-chain, styrene, aliphatic branched-chain, and trans-butadiene, respectively. An aliphatic-long chain, aliphatic branched-chain, and trans-butadiene were soft segments in asphalt while styrene was the rigid segment. The soft segments affect the intramolecular friction, orientation, and thermal motion at low temperatures, whereas the rigid segment enhances the strength of polymer networks. Thus, the anti-cracking property of polymer-modified asphalt can be improved by adjusting the ratio of soft and rigid segments in the polymer modifier.

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1397
Author(s):  
Nappaphan Kunanusont ◽  
Boonchai Sangpetngam ◽  
Anongnat Somwangthanaroj

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.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2434
Author(s):  
Laura Moretti ◽  
Nico Fabrizi ◽  
Nicola Fiore ◽  
Antonio D’Andrea

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.


2020 ◽  
Vol 982 ◽  
pp. 195-200
Author(s):  
Abdullah Al Mamun ◽  
Okan Sirin

Nanotechnology has contributed significantly to different subfields of the construction industry, including asphalt pavement engineering. The improved properties and new functionalities of the nanomaterials have provided different desired properties of asphalt. In this study, the effectiveness of multi-walled carbon nanotubes (MWCNT) in resisting the oxidation of polymer-modified asphalt was measured. A total of three different percentages (0.5%, 1%, and 1.5%) of MWCNT were used to modify the Styrene-Butadiene (SB) and styrene–butadiene–styrene (SBS) modified asphalt (4% and 5%). The laboratory oxidized asphalt samples were evaluated by an atomic force microscopy machine. The oxidation of the polymer-MWCNT modified asphalt is measured by simulating the existing functional group of the asphalt and as a function of the adhesive force. It is observed that the use of MWCNT in SB and SBS can increase the resistance to oxidation.


2011 ◽  
Vol 71-78 ◽  
pp. 5038-5041
Author(s):  
Chang Qing Fang ◽  
Min Zhang ◽  
Jing Bo Hu ◽  
Ying Zhang ◽  
Rui En Yu

Asphalt aging is inevitable to the asphalt pavement performance, which will lead asphalt to hardening gradually and becoming brittle. Therefore, aging progress shortens the life of asphalt, but the study on polymer asphalt improves the phenomenon. The present situation on aging of polymer modified asphalt is summarized and the aging mechanism of modified asphalts is analyzed in the paper. Otherwise, the research progress at home and abroad on the aging properties of modified asphalt is introduced by a series of characterization techniques, which include mechanics technique, rheology technique, FTIR, GPC and so on


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