Low-Temperature and Fatigue Characteristics of Degraded Crumb Rubber–Modified Bitumen Before and After Aging

Author(s):  
Sheng Wang ◽  
Weidong Huang ◽  
Peng Lin
Author(s):  
Haopeng Wang ◽  
Xueyan Liu ◽  
Panos Apostolidis ◽  
Sandra Erkens ◽  
Athanasios Skarpas

Rubber swelling in bitumen, which is a diffusion-induced volume expansion process, plays a dominant role in the design of crumb rubber modified bitumen binders and their properties development. This study aims to investigate the kinetics of bitumen diffusion into truck tire rubber, the equilibrium swelling characteristics of rubber, and the mechanical properties of rubber before and after swelling at different high temperatures. Fourier transform infrared spectroscopy results indicate that no rubber dissolution happens during the interaction in the temperature range from 160°C to 200°C. Aliphatic compounds from bitumen preferentially diffused into rubber during the swelling process. The diffusion coefficients of bitumen into rubber were determined by the sorption test using the gravimetric method. The diffusion coefficient increases with the increase of temperature in an Arrhenius form. The volume expansion of rubber during swelling was captured by the X-ray computed tomography scan images. Rubber swells faster at the earlier stages, then the expansion rate slows down. The swelling ratio of rubber increased from 1.97 at 160°C to 3.03 at 200°C after 36 h interaction. Mechanical tests by dynamic shear rheometer reveal that swollen rubber becomes softer compared with the dry rubber and exhibits obvious viscoelastic behaviors. With the increase of temperature, the softening and viscous effect are more significant. The obtained parameters can be implemented to swelling and micromechanical models to better predict the binder properties.


2019 ◽  
Vol 234 ◽  
pp. 1262-1274 ◽  
Author(s):  
Zixuan Chen ◽  
Tao Wang ◽  
Jianzhong Pei ◽  
Serji Amirkhanian ◽  
Feipeng Xiao ◽  
...  

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2345 ◽  
Author(s):  
Yangsheng Ye ◽  
Gang Xu ◽  
Liangwei Lou ◽  
Xianhua Chen ◽  
Degou Cai ◽  
...  

In this study, a new type of composite modified bitumen was developed by blending styrene-butadiene-styrene (SBS) and crumb rubber (CR) with a chemical method to satisfy the durability requirements of waterproofing material in the waterproofing layer of high-speed railway subgrade. A pressure-aging-vessel test for 20, 40 and 80 h were conducted to obtain bitumen samples in different long-term aging conditions. Multiple stress creep recovery (MSCR) tests, linear amplitude scanning tests and bending beam rheometer tests were conducted on three kinds of asphalt binders (SBS modified asphalt, CR modified asphalt and SBS/CR composite modified asphalt) after different long-term aging processes, including high temperature permanent deformation performance, resistance to low temperature thermal and fatigue crack. Meanwhile, aging sensitivities were compared by different rheological indices. Results showed that SBS/CR composite modified asphalt possessed the best properties before and after aging. The elastic property of CR in SBS/CR composite modified asphalt improved the ability to resist low temperature thermal and fatigue cracks at a range of low and middle temperatures. Simultaneously, the copolymer network of SBS and CR significantly improved the elastic response of the asphalt SBS/CR modified asphalt at a range of high temperatures. Furthermore, all test results indicated that the SBS/CR modified asphalt possesses the outstanding ability to anti-aging. SBS/CR is an ideal kind of asphalt to satisfy the demand of 60 years of service life in the subgrade of high speed railway.


2021 ◽  
Vol 1035 ◽  
pp. 951-957
Author(s):  
Yan Heng He ◽  
Zhi Long Cao ◽  
Yang Yang Ge ◽  
Zhao Yang Liu ◽  
Jiang Ting Li ◽  
...  

The properties of SBS modified bitumen waterproof membrane (SMBM) will deteriorate under the action of heat. In this paper, SBS modified bitumen (SMB) and SMBM were aged at 80 °C for different times (0,10,20,30,40 days). The low temperature flexibility, softening point, viscosity and mass changes ratio of SMB and mechanical properties of SMBM before and after aging were tested, the microstructure and chemical structure of SMB were investigated by fluorescence microscope (FM) and Fourier transform infrared spectroscopy (FTIR). The results show that the low temperature flexibility, softening point and viscosity of SMB decrease significantly at the initial stage of heat aging (10 days), especially the influence of heat aging on the low temperature flexibility and viscosity of SMB is more obvious, and their properties degradation rate slowdown in the later stage of aging. The mass changes ratio of SMB first decreases and then increases with aging time. FM shows that the network crosslinking structure of SMB is destroyed gradually with the extension of aging time. The network crosslinking structure disappears after 40 days of heat aging. FTIR shows that carbonyl and sulfoxide compounds are increasing after aging, more carbonyl compounds than sulfoxide compounds are formed after aging for 10 days, and the degradation rate of SBS decreases. The maximum tension of SMBM first increases and then decreases, the elongation at maximum tension decreases with aging time.


2019 ◽  
Vol 207 ◽  
pp. 44-56 ◽  
Author(s):  
Miguel A. Franesqui ◽  
Jorge Yepes ◽  
Cándida García-González ◽  
Juan Gallego

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 857 ◽  
Author(s):  
Yongchun Cheng ◽  
Chao Chai ◽  
Chunyu Liang ◽  
Yu Chen

In this paper, the performance of a warm-mixed porous asphalt mixture (PAM) with steel slag as aggregate and crumb-rubber–SBS (styrene-butadiene-styrene) modified bitumen as a binder was studied. Two kinds of warming additives were used, namely ethylene bis stearic acid amide (EBS) and stearic acid amide (SA). The mixtures were investigated for their permeability, Marshall stability, low-temperature crack resistance, and underwent a rutting test, water sensitivity evaluation and Cantabro particle loss test. Then, the viscoelastic and dynamic characteristics of the mixtures were also analyzed. The results showed that the addition of the warming additives allowed the decrease of the manufacturing temperature by 10 °C. Thus, the addition of warming additives significantly improves the low-temperature crack resistance and slightly reduces the water sensitivity, weakly increases the permeability, and has little effect on the resilient modulus. Since the addition of SA significantly improves the low-temperature crack resistance and rutting resistance of the PAM, SA is therefore recommended for pavement engineering in seasonal frozen regions.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2136 ◽  
Author(s):  
Rui He ◽  
Shuhua Wu ◽  
Xiaofeng Wang ◽  
Zhenjun Wang ◽  
Huaxin Chen

Temperature sensitivity characteristics of bitumen can be evidently influenced by modifier types and natural aging processes. Many types of modifiers have been used to improve the temperature sensitivity performance of bitumen, but their effects are different. Therefore, different bitumen specimens as well as SBS/CRP (Styrene-butadiene-styrene polymer/crumb rubber powder)-modified bitumen were prepared and the temperature sensitivity characteristics of bitumen after different aging processes were analyzed in this study. A dynamic rheological property test and performance test at low temperature were carried out to analyze temperature sensitivity and low temperature rheological properties of bitumen. An infrared spectrum test was adopted to study the effect of functional groups under different aging process on the properties of bitumen. The relationship between macroscopic properties and microstructures of bitumen was analyzed. The results show that SBS/CRP-modified bitumen has a strong anti-aging ability in that its flexibility and structure remain in a good condition after long-term aging. The aging process has no significant effect on SBS/CRP-modified bitumen. SBS/CRP-modified bitumen has an excellent low-temperature relaxation ability and low-temperature crack resistance. In contrast to original bitumen and SBS-modified bitumen, the temperature sensitivity performance of SBS/CRP-modified bitumen is evidently enhanced. The physical blending effect is dominant in the bitumen modified process and there is no evident chemical reaction between bitumen and crumb rubber powder. SBS/CRP-modified bitumen is recommended for wide use in plateau areas with ultraviolet and cold surroundings.


2015 ◽  
Vol 1094 ◽  
pp. 253-260
Author(s):  
Lan Wang ◽  
Yong Jie Jia ◽  
Lei Feng

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.


Author(s):  
Muhammad Saad Waheed ◽  
Manzoor Elahi

Two grades of bitumen, (60/70 and 80/100), were modified by addition of Local Crumb Rubber (LCR) by weight of base bitumen. To investigate the effects of short-term aging on modified and LCR modified bitumen, Rolling Thin Film Oven (RTFO) test was used to simulate the short term aging. Dynamic shear rheometer (DSR) was used to assess the rheological properties of bitumen, both before and after aging. It was observed that at 65 degree Celcius on aging, the phase angle (sigma) of unmodified bitumen decreased by 3 and 4% for 60/70 and 80/100 bitumen respectively; whereas, for 60/70 LCR modified bitumen, the phase angle (sigma) on RTFO aging decreased by 7% for all LCR content (10, 15 and 20%) by weight of base bitumen. However, on RTFO aging (sigma), values for LCR modified 80/100 bitumen varied across different LCR content and could not be generalized. The complex modulus |G*| of LCR modified 60/70 bitumen increased on aging for both modified and unmodified bitumen at 65C, but with the increase in LCR content, the difference between bitumen aged and un-aged values of |G*| was considerably lowered. An interesting finding was for 80/100 bitumen modified with 20% LCR content by weight, which showed a reduction in |G*| values and an increase in (sigma) values on aging. This shows that to some extent, LCR compensates for the stiffening effects of aging.


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