scholarly journals Evaluation of the Cohesive Properties of SBS-Modified Binders at Low Temperatures

2021 ◽  
Vol 29 (1) ◽  
pp. 27-34
Author(s):  
Baha Vural Kök ◽  
Yunus Erkuş ◽  
Mehmet Yilmaz

Abstract The durability, fatigue resistance, and low-temperature behavior of asphalt layers are greatly affected by the properties of bitumen. Therefore, the composition of bitumen is frequently modified to improve the performance of asphalt mixtures. Sty-rene-butadiene-styrene (SBS) has been the most often used additive recently. Researchers are trying to improve the cohesive and adhesive properties of binders by such polymer-based additives. In this study, 160/220 penetration grade bitumen and Kraton D 1101 SBS were used. The present study contains a new evaluation for determining the cohesive behavior of SBS-modified binders at -1°C, -3°C, and -5°C. The results of this evaluation were compared to conventional and rheological test results. Penetration, softening point, viscosity, dynamic shear rheometer, and bending beam rheometer tests were therefore conducted. Finally, the results of a low-temperature tensile test were found to be consistent with the results of the other tests; hence, they also confirm the cohesive behavior of SBS-modified binders at low temperatures.

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yuefeng Zhu ◽  
Yanwei Li ◽  
Chundi Si ◽  
Xiaote Shi ◽  
Yaning Qiao ◽  
...  

In recent years, the significant demand for sustainable paving materials has led to a rapid increase in the utilization of reclaimed asphalt pavement (RAP) materials. When RAP is mixed with virgin asphalt concrete, particularly when its percentage is high, performance of the binder and asphalt concrete can be adversely affected. For this reason, different types of additives need to be identified and evaluated beforehand to mitigate the adverse effects. In this study, different types of fiber materials were identified and selected as binder/mixture additives, including lignin fiber (LF), polyester fiber (PF), and basalt fiber (BF). Various samples of fiber-modified binders and asphalt mixtures with different RAP contents (0%, 20%, and 40%) were prepared and were evaluated using two sets of laboratory testing: (i) dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests were performed to study the rheological properties of fiber-modified binders; (ii) the wheel tracking test, bending creep test, moisture susceptibility test, fatigue test, and self-healing fatigue test were conducted to characterize the laboratory properties of fiber-modified RAP mixtures. Test results for the modified binders show that the BF-modified binder has the greatest positive effect on the high-temperature performance of the asphalt binder, followed by PF- and LF-modified binders. However, the virgin asphalt shows the best low-temperature property than the fiber-modified asphalt binder. Test results for the whole RAP mixtures show that all fibers have a significant effect on the properties (including high- and low-temperature stability, moisture susceptibility, fatigue, and self-healing ability) of RAP mixtures. Among them, adding BF shows the greatest improvement in high-temperature stability, fatigue resistance, and self-healing ability of RAP mixtures. LF is found to significantly enhance low-temperature properties, and PF can greatly improve the resistance to moisture damage of RAP mixtures. For high percentage of RAP using on sites, adding multiple additives may further enhance its durability.


2021 ◽  
Vol 6 (4) ◽  
pp. 58
Author(s):  
Ana Dias ◽  
Hugo Silva ◽  
Carlos Palha ◽  
Joel Oliveira

When temperatures drop to significantly low levels, road pavements are subjected to thermally-induced stresses, resulting in the appearance of thermal cracking, among other distresses. In these situations, polymers can be used as asphalt binder modifiers to improve certain asphalt binder properties, such as elastic recovery, cohesion, and ductility. Polymers also minimize some of the problems of asphalt mixtures, such as thermal and fatigue cracking and permanent deformation. This work’s objective was to study the behavior of asphalt mixtures at low temperatures, mainly when using modified binders. Thus, three binders were selected and tested: a standard 50/70 penetration grade bitumen and two polymer-modified binders (PMB), obtained by adding, respectively, 2.5% and 5.0% of styrene–butadiene–styrene (SBS) in the 50/70 pen grade bitumen. Then, the PMBs were incorporated into stone mastic asphalt mixtures (namely SMA 11), which were subjected to low-temperature mechanical tests based on the most recent European Standards. The asphalt binders and mixtures evaluated in this work were tested for thermal cracking resistance, creep, elastic recovery, cohesive strength, and ductility strength. Overall, it is concluded that the studied asphalt mixtures with PMB, with just 2.5% SBS, performed adequately at low temperatures down to −20 °C.


2018 ◽  
Vol 45 (6) ◽  
pp. 469-477 ◽  
Author(s):  
Sevil Köfteci ◽  
Perviz Ahmedzade ◽  
Taylan Günay

The aim of this paper is to examine the effects of ground plastic pipe wastes on bitumen. For this purpose, three modified bitumen samples with modifier contents of 2%, 4%, and 6% along with pure bitumen were prepared and tested. To understand the effect of modifier on bitumen, conventional bitumen tests, rotational viscosity tests at 135 °C and 165 °C, dynamic shear rheometer tests at three different frequencies that represent three different traffic speeds, and bending beam rheometer (BBR) test were performed. The BBR test results showed that resistance of pure bitumen to low-temperature cracking increased by using additives up to 4%. Based on the results of this study, it can be said that waste plastic pipes can be used as modifier for the bitumen binder. The 4% additive showed the best performance.


Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4910
Author(s):  
Ping Zhang ◽  
Lan Ouyang ◽  
Lvzhen Yang ◽  
Yi Yang ◽  
Guofeng Lu ◽  
...  

As environmentally friendly materials, carbon black and bio-oil can be used as modifiers to effectively enhance the poor high-temperature and low-temperature performance of base asphalt and its mixture. Different carbon black and bio-oil contents and shear time were selected as the test influencing factors in this work. Based on the Box–Behnken design (BBD), carbon black/bio-oil composite modified asphalt was prepared to perform the softening point, penetration, multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests. The response surface method (RSM) was used to analyze the test results. In addition, the base asphalt mixtures and the optimal performance carbon black/bio-oil composite modified asphalt mixtures were formed for rutting and low-temperature splitting tests. The results show that incorporating carbon black can enhance the asphalt’s high-temperature performance by the test results of irrecoverable creep compliance (Jnr) and strain recovery rate (R). By contrast, the stiffness modulus (S) and creep rate (M) test results show that bio-oil can enhance the asphalt’s low-temperature performance. The quadratic function models between the performance indicators of carbon black/bio-oil composite modified asphalt and the test influencing factors were established based on the RSM. The optimal performance modified asphalt mixture’s carbon black and bio-oil content was 15.05% and 9.631%, and the shear time was 62.667 min. It was revealed that the high-temperature stability and low-temperature crack resistance of the carbon black/bio-oil composite modified asphalt mixture were better than that of the base asphalt mixture because of its higher dynamic stability (DS) and toughness. Therefore, carbon black/bio-oil composite modified asphalt mixture can be used as a new type of choice for road construction materials, which is in line with green development.


2017 ◽  
Vol 50 (3) ◽  
pp. 256-275 ◽  
Author(s):  
Mahdi Delaviz Bayekolaei ◽  
Koorosh Naderi ◽  
Fereidoon Moghadas Nejad

In recent years, the use of nano materials for improving various mechanical and performance-related properties of polymer-modified asphalt binders has been growing rapidly. However, few researches investigated the effects of base binder and styrene–butadiene–styrene (SBS) structure on rutting resistance of polymer-nanocomposite-modified asphalt mixtures. This study investigated the effect of polymer–nanocomposite modification, using two different penetration grade asphalt binders and two types of SBS, on rutting properties of asphalt mixtures. Rheological properties of modified binders, Marshall stability, resilient modulus, and rut depth in wheel-tracking tests were used to evaluate the rutting performance of the modified binders and mixtures. The results indicated that both base binder type and SBS structure had significant effect on rutting resistance of polymer-nanocomposite-modified asphalt mixtures.


1950 ◽  
Vol 23 (4) ◽  
pp. 770-785
Author(s):  
S. D. Gehman ◽  
P. J. Jones ◽  
C. S. Wilkinson ◽  
D. E. Woodford

Abstract The generally observed stiffening of elastomers at low temperatures may be supplemented by the occurrence of crystallization if the elastomers have sufficient regularity of molecular structure and other conditions are favorable. To study these effects, observations of the progressive stiffenings of elastomer compounds at low temperatures were made by measurements of the relative torsional modulus of test strips mounted in racks which were stored at low temperature. The periods of observation extended over 30 to 60 days with temperatures in the range from −59° to −18° C. A correlation was found between density changes due to crystallization as determined dilatometrically and torsional stiffness changes. Factors studied in addition to temperature included compounding variables such as cure and plasticizer content. Some data were obtained to show the acceleration of crystallization due to compressive stress. Progressive stiffening due to crystallization was observed for vulcanizates of Hevea, Neoprene Type GN, and Butyl rubber, as well as for an 85-15 butadiene-styrene redox-type copolymer. The results were interpreted in accordance with concepts of crystal nucleation and growth with necessary modifications due to the molecular structure of elastomers. Although the phenomenon of spontaneous crystallization of elastomers was found to be complicated by many factors, a useful degree of generality appears in some of the results.


2007 ◽  
Vol 13 (4) ◽  
pp. 307-315 ◽  
Author(s):  
Piotr Radziszewski

Permanent deformations, primarily in the form of ruts, are one of the basic asphalt pavement damages impairing its service properties. Application of appropriate asphalt mixtures and binder modification are effective methods for improving asphalt courses resistance. While being manufactured, stored, fitted into a road pavement and during long term service, bitumen binders and asphalt mixtures are subject to continuous unfavourable ageing processes during which pavement courses characteristics change considerably, resistance to permanent deformations being among them. This article presents rut and dynamic creep test results of concrete, SMA (stone mastic asphalt), MNU (thin courses of non‐continuous grain mixtures), Superpave mixture and porous asphalt mixture of two air void content percentages: 15 %, 20 %. Asphalt concrete mixtures, MNU's and porous asphalt mixtures contained elastomer, plastomer and fine rubber modified binders. Samples for laboratory rut tests were made by slab compaction because this method, as the author's previous research had shown, was the closest to ‘in‐situ’ conditions. Resistance to permanent deformations of the examined specimens was evaluated before aging, after technological aging (short term ageing) and after service ageing (long‐term ageing). The test results show that resistance to permanent deformations depends on the kind of asphalt mixture and binder applied. Concrete asphalts with fine rubber modified bitumens and concrete asphalts with 7 % polymer modified binders as well as SMA's and Superpave mixtures with unmodified binders appeared to be most resistant to permanent deformations after a long‐term laboratory ageing. It was proved that the overall evaluation of resistance to permanent deformations could be obtained by rut and creep testing of asphalt mixtures exposed to short‐ and long‐term ageing. Simultaneous determining 4 parameters: maximum rut depth after short‐term ageing, rutting coefficient after operational ageing, stiffness creeping modulus after long‐term ageing and cumulated deformation after short‐term ageing, facilitates full characteristics of modified asphalt mixes designed to be built in the wearing course of a road pavement.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Hassan Fazaeli ◽  
Hamid Behbahani ◽  
Amir Ali Amini ◽  
Jafar Rahmani ◽  
Golazin Yadollahi

This paper presents the results of an experimental research on the effects of “Fischer Tropsch-Paraffin” (Sasobit) content on physical and rheological properties of Sasobit modified bitumen at various operational temperatures. For this purpose, bitumen with a Performance Grade (PG) of 58–22 is selected as the base and later it is modified with 1, 2, 2.5, 3, and 4 weight percent of FT-Paraffin (Sasobit). The performance of modified bitumen at high, intermediate, and low temperatures is evaluated based on Strategic Highway Research Program (SHRP) Superpave tests. Results of the study show that FT-paraffin improves the performance of bitumen at high temperatures in addition to increasing the resistance of mixture against permanent deformation. Despite the advantages of FT-paraffin on bitumen performance at high temperatures, it does not show a considerable influence on the intermediate and low temperature performance of bitumen. The effect of FT-paraffin content on the viscosity of modified bitumen is also investigated using Brookfield Viscometer Apparatus. Results show that increasing the additive content lowers the viscosity of modified bitumen. This in return can reduce the mixing and compaction temperature of asphalt mixtures.


Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 202 ◽  
Author(s):  
Marcin Stienss ◽  
Cezary Szydlowski

Warm mix asphalt (WMA) has been widely accepted as a future asphalt paving technology. Besides clear advantages, there are still some concerns regarding durability and long-term performance of pavements made with this type of asphalt mixtures. One of the most important issues is low temperature behaviour of WMA because certain additives used for temperature reduction can affect bitumen properties. This paper presents the evaluation of low-temperature properties of laboratory-produced asphalt concrete for wearing course with selected WMA additives. One type of bitumen with paving grade 50/70 and five WMA additives of different nature (organic, surface tension reducer and combination of both) were used in this study. The production and compaction temperature of mixtures containing WMA additives was 25 °C lower in comparison with the temperature of the reference mix. To assess the susceptibility of WMA to low-temperature cracking, Semi-Circular Bending (SCB) and Thermal Stress Restrained Specimen Test (TSRST) were used. Supplementary rating was made by analysing Bending Beam Rheometer (BBR) test results of asphalt binders.


Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5090 ◽  
Author(s):  
Bing Zhu ◽  
Hanbing Liu ◽  
Wenjun Li ◽  
Chunli Wu ◽  
Chao Chai

Acoustic emission (AE), as a nondestructive testing (NDT) and real-time monitoring technique, could characterize the damage evolution and fracture behavior of materials. The primary objective of this paper was to investigate the improvement mechanism of steel slag on the low-temperature fracture behavior of permeable asphalt mixtures (PAM). Firstly, steel slag coarse aggregates were used to replace basalt coarse aggregates with equal volume at different levels (0%, 25%, 50%, 75%, and 100%). Then, the low-temperature splitting test with slow loading was used to obtain steady crack growth, and the crack initiation and propagation of specimens were monitored by AE technique in real time. From the low-temperature splitting test results, SS-100 (permeable asphalt mixtures with 100% steel slag) has the optimal low-temperature cracking resistance. Therefore, the difference of fracture behavior between the control group (permeable asphalt mixtures without steel slag) and SS-100 was mainly discussed. From the AE test results, a slight bottom-up trend of sentinel function was founded in the 0.6–0.9 displacement level for SS-100, which is different from the control group. Furthermore, the fracture stages of the control group and SS-100 could be divided based on cumulative RA and cumulative AF curves. The incorporation of 100% steel slag reduced the shear events and restrained the growth of shear cracking of the specimen in the macro-crack stage. Finally, the considerable drops of three kinds of b-values in the final phase were found in the control group, but significant repeated fluctuations in SS-100. In short, the fracture behavior of PAM under low temperature was significantly improved after adding 100% steel slag.


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