scholarly journals Low-Temperature Performance of Polymer-Modified Binders in Stone Mastic Asphalts

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.

2021 ◽  
Vol 13 (18) ◽  
pp. 10271
Author(s):  
Yuchen Guo ◽  
Xuancang Wang ◽  
Guanyu Ji ◽  
Yi Zhang ◽  
Hao Su ◽  
...  

The deteriorating ecological environment and the concept of sustainable development have highlighted the importance of waste reuse. This article investigates the performance changes resulting from the incorporation of shellac into asphalt binders. Seashell powder-modified asphalt was prepared with 5%, 10%, and 15% admixture using the high-speed shear method. The microstructure of the seashell powder was observed by scanning electron microscope test (SEM); the physical-phase analysis of the seashell powder was carried out using an X-ray diffraction (XRD) test; the surface characteristics and pore structure of shellac were analyzed by the specific surface area Brunauer-Emmett-Teller (BET) test; and Fourier infrared spectroscopy (FTIR) qualitatively analyzed the composition and changes of functional groups of seashell powder-modified asphalt. The conventional performance index of seashell powder asphalt was analyzed by penetration, softening point, and ductility (5 °C) tests; the effect of seashell powder on asphalt binder was studied using a dynamic shear rheometer (DSR) and bending beam rheometer (BBR) at high and low temperatures, respectively. The results indicate the following: seashell powder is a coarse, porous, and angular CaCO3 bio-material; seashell powder and the asphalt binder represent a stable physical mixture of modified properties; seashell powder improves the consistency, hardness, and high-temperature performance of the asphalt binder but weakens the low-temperature performance of it; seashell powder enhances the elasticity, recovery performance, and permanent deformation resistance of asphalt binders and improves high-temperature rheological properties; finally, seashell powder has a minimal effect on the crack resistance of asphalt binders at very low temperatures. In summary, the use of waste seashells for recycling as bio-modifiers for asphalt binders is a practical approach.


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.


2019 ◽  
Vol 9 (13) ◽  
pp. 2697
Author(s):  
Gabriela Ceccon Carlesso ◽  
Glicério Trichês ◽  
João Victor Staub de Melo ◽  
Matheus Felipe Marcon ◽  
Liseane Padilha Thives ◽  
...  

Fatigue cracking and rutting are among the main distresses identified in flexible pavements. To reduce these problems and other distresses, modified asphalt mixtures have been designed and studied. In this regard, this paper presents the results of a study on rheological behavior and resistance to permanent deformation and to fatigue of four different asphalt mixtures: (1) with conventional asphalt binder (CAP 50/70); (2) with binder modified by nanoclay (3% NC); (3) with binder modified by styrene–butadiene–styrene polymer (SBS 60/85); and (4) with binder modified by nanoclay and SBS (3% NC + 2% SBS). For this analysis, the mixtures were evaluated based on complex modulus, permanent deformation tests, and fatigue tests (4PB, in the four-point bending apparatus), with the subsequent application of numerical simulations. The results obtained show a better rheological behavior related to greater resistance to permanent deformation for the mixture 3% NC + 2% SBS, which could represent an alternative for roads where a high resistance to rutting is required. Otherwise, on fatigue tests, higher resistance was observed for the SBS 60/85 mixture, followed by the 3% NC + 2% SBS mixture. Nevertheless, based on the results of the numerical simulations and considering the possibility of cost reduction for the use of the 3% NC + 2% SBS mixture, it is concluded that this modified material has potential to provide improvements to the road sector around the world, especially in Brazil.


TRANSPORTES ◽  
2020 ◽  
Vol 28 (2) ◽  
pp. 76-86
Author(s):  
Luis Miguel Gutierrez Klinsky ◽  
Vivian Silveira dos Santos Bardini ◽  
Valeria Cristina De Faria

This study used the Multiple Stress Creep Recovery Test (MSCR) and the Flow number test to analyze the characteristics of asphalt rubber and its use in hot mix asphalt (HMA) regarding to their ability to withstand permanent deformation. MSCR tests were done in three commercial asphalt rubber and in the traditional asphalt binder 50/70. Flow number tests were performed in twenty four specimens of asphalt rubber mixtures and eight specimens of conventional asphalt mixtures. The results of these tests showed that all the asphalt rubber samples had lower compliance values (Jnr) in the MSCR test, which denotes that these modified binders improved the rutting resistance of HMA. This behavior was confirmed with flow number results, since the HMA produced with asphalt rubber had always higher flow number values, when compared to the conventional asphalt mixtures. The analysis of the data showed excellent correlation between Jnr values and FN values.


Author(s):  
Ali Arabzadeh ◽  
Joseph H. Podolsky ◽  
Maxwell D. Staver ◽  
R. Christopher Williams ◽  
Austin D. Hohmann ◽  
...  

In this study, asphalt mixtures were engineered with bio-renewable soybean oil-derived modifiers, and then used for pavement demonstration projects in the U.S. states of Iowa and Minnesota in the summer of 2019. The performance grade, elastic recovery (R), and non-recoverable creep compliance (Jnr) of the binders were evaluated. The modification of asphalt binder for the Iowa project almost maintained the high and low temperature grades, and the presence of modifier in the mixture of Minnesota project resulted in a slight decrease in the low temperature grade while maintaining the high temperature grade. The Jnr and R values proved the increase of elasticity and relaxation of the asphalt binder modified for the Iowa project. The Jnr calculated for the Minnesota project revealed a considerable increase in the relaxation of the asphalt binder. Disc-shaped compact tension, Hamburg wheel tracking, and push-pull were the mechanical performance tests performed on the mixtures. Based on the results obtained from these tests, the Iowa mixture, produced with modified asphalt binder, showed a significant improvement in resistance to low-temperature cracking, rutting, moisture damage, and fatigue cracking. The Minnesota mixture, modified in the plant, showed a significant improvement in the fatigue performance and a slight improvement in low-temperature cracking resistance.


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.


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.


Author(s):  
F. Bonemazzi ◽  
V. Braga ◽  
R. Corrieri ◽  
C. Giavarini ◽  
F. Sartori

The properties of a number of polymers commonly proposed for polymer-modified bitumens (PMBs) were studied to suggest a way to select the polymer suitable for the required application; the prediction of the performance in the final application would allow bypass of the tests on PMBs and asphalt mixtures. Rheological and mechanical tests were performed on both raw materials and PMBs containing 5 percent polymer. Tensile dynamic mechanical test analyzer hardness, tensile properties, and tension set tests were conducted on polymers; the tendency of the polymers to absorb aromatic oil was also determined to simulate their swelling in the PMBs. Rheometer dynamic tests, R&B, penetration, and elastic recovery were carried out on PMBs. Rheometer dynamic parameters, R&B, penetration, and elastic recovery were measured on the bitumen. The experimental data confirm that selected tests on polymers can give good information about the polymer contribution to PMBs' performances.


Author(s):  
H. Barry Takallou ◽  
Hussain U. Bahia ◽  
Dario Perdomo ◽  
Robert Schwartz

The effect of different mixing times and mixing temperatures on the performance of asphalt-rubber binder was evaluated. Four different types of asphalt-rubber binders and neat asphalt were characterized using the Strategic Highway Research Program (SHRP) binder method tests. Subsequently, mix designs were carried out using both the SHRP Levels I and II mix design procedures, as well as the traditional Marshall mix design scheme. Additionally, performance testing was carried out on the mixtures using the Superpave repetitive simple shear test at constant height (RSST-CH) to evaluate the resistance to permanent deformation (rutting) of the rubberized asphalt mixtures. Also, six rectangular beams were subjected to repeated bending in the fatigue tester at different microstrain levels to establish rubberized asphalt mixtures’ resistance to fatigue cracking under repeated loadings. The results indicate that the Superpave mix design produced asphalt-rubber contents that are significantly higher than values used successfully in the field. Marshall-used gyratory compaction could not produce the same densification trends. Superpave mixture analysis testing (Level II) was used successfully for rubberized asphalt mixtures. Results clearly indicated that the mixture selected exhibited acceptable rutting and fatigue behavior for typical new construction and for overlay design. Few problems were encountered in running the Superpave models. The results of the RSST-CH indicate that rubber-modified asphalt concrete meets the criteria for a maximum rut depth of 0.5 in.; and more consistent results were measured for fatigue performance analysis using the repeated four-point bending beam testing (Superpave optional torture testing). The cycles to failure were approximately 26,000 at 600 microstrain.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5277
Author(s):  
Shiqi Wang ◽  
Huanyun Zhou ◽  
Xianhua Chen ◽  
Minghui Gong ◽  
Jinxiang Hong ◽  
...  

Semi-flexible pavement (SFP) is widely used in recent years because of its good rutting resistance, but it is easy to crack under traffic loads. A large number of studies are aimed at improving its crack resistance. However, the understanding of its fatigue resistance and fatigue-cracking mechanism is limited. Therefore, the semi-circular bending (SCB) fatigue test is used to evaluate the fatigue resistance of the SFP mixture. SCB fatigue tests under different temperature values and stress ratio were used to characterize the fatigue life of the SFP mixture, and its laboratory fatigue prediction model was established. The distribution of various phases of the SFP mixture in the fracture surface was analyzed by digital image processing technology, and its fatigue cracking mechanism was analyzed. The results show that the SFP mixture has better fatigue resistance under low temperature and low stress ratio, while its fatigue resistance under other environmental and load conditions is worse than that of asphalt mixture. The main reason for the poor fatigue resistance of the SFP mixture is the poor deformation capacity and low strength of grouting materials. Furthermore, the performance difference between grouting material and the asphalt binder is large, which leads to the difference of fatigue cracking mechanism of the SFP mixture under different conditions. Under the fatigue load, the weak position of the SFP mixture at a low temperature is asphalt binder and its interface with other materials, while at medium and high temperatures, the weak position of the SFP mixture is inside the grouting material. The research provides a basis for the calculation of the service life of the SFP structure, provides a reference for the improvement direction of the SFP mixture composition and internal structure.


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