scholarly journals Microscopic Properties of Hydrogen Peroxide Activated Crumb Rubber and Its Influence on the Rheological Properties of Crumb Rubber Modified Asphalt

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1434 ◽  
Author(s):  
Bo Li ◽  
Hao Li ◽  
Yongzheng Wei ◽  
Xingjun Zhang ◽  
Dingbang Wei ◽  
...  

Crumb rubber modified (CRM) asphalt binder has been affirmed to improve resistance to rutting, moisture susceptibility, low-temperature cracking, and asphalt durability. However, CRM has poor compatibility with asphalt since crumb rubber molecules are vulcanized. The objective of this study was to develop a new method to prepare activated crumb rubber using hydrogen peroxide (H2O2) solution and to explore the rheological properties of H2O2 activated CRM (ACRM) asphalt. Three different percentages of H2O2 solution were used to activate crumb rubber. The surface properties of oxidized rubber were analysed using scanning electron microscopy. Moreover, the pore structure in rubber powder was investigated. The rheological properties of bitumen samples obtained from treated and untreated rubber were characterized by conducting dynamic shear rheometer tests. The test results show that the average pore size of the crumb rubber after activation with H2O2 solution is significantly smaller than that of the inactivated crumb rubber, and the volume and surface area of the crumb rubber pores change with H2O2 solution activation in a certain pattern. With the increase in H2O2 solution content, the contact surface between the particles increases, the floccules and pores of the powder increase, and the interface degree between the crumb rubber powder and the asphalt is strengthened. Solubility of the rubber hydrocarbon and the release ability of the carbon black particles from the crumb rubber in the asphalt binder increase, but the mechanical properties of the crumb rubber, including the strength, elasticity, and wear resistance, decrease. As a result, a reduction is observed in the elasticity, viscosity, high-temperature rutting resistance, and elasticity of the ACRM asphalt.

Author(s):  
Weidong Huang ◽  
Lu Zhou

Moisture damage is a prominent problem of asphalt pavements. The bond strength between asphalt and aggregates is a crucial factor that influences the capability of asphalt to resist moisture-induced damage. In this study, a binder bond strength (BBS) test was conducted to evaluate the effects of various modifiers and additives of different amounts on bond strength between asphalt and aggregates. Furthermore, the influence of styrene–butadiene–styrene (SBS) on adhesion behavior of asphalt binder was investigated through a gel permeation chromatography (GPC) test. Finally, the results of the BBS test were compared with the findings obtained from a Hamburg wheel-tracking device (HWTD) test, which reflected the moisture sensitivity of mixtures under wet conditions. Results indicated that gilsonite, high-density polyethylene, and polyphosphoric acid improved the bond strength of the base asphalt; SBS had no positive effects on asphalt adhesion properties; and SBS at a low amount reduced the bond strength. Ethylene bis-stearamide wax, crumb rubber, terminal blend (TB) rubber powder, and compound modifier TB rubber powder plus SBS decreased the bond strength. The GPC test results showed that SBS possibly did not actively contribute to the formation of bond strength between asphalt and aggregates. Test data for BBS and HWTD tests under wet conditions confirmed that there was no discernible correlation between these two tests when adhesion properties of modified asphalts were evaluated. However, the results of the BBS test were in accordance with those of the HWTD test when the adhesion of asphalt with different amounts of the same modifier and the mixture resistance to water damage were evaluated.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2693
Author(s):  
Weihong Liu ◽  
Yishen Xu ◽  
Hongjun Wang ◽  
Benan Shu ◽  
Diego Maria Barbieri ◽  
...  

Segregation of waste crumb rubber powder (WR) modified asphalt binders the large-scale application of WR in asphalt. The method of microwave activation combined with chemical activation (KMWR) was proposed to improve storage stability and rheological properties of WR modified asphalt in this work. Storage stability and rheological properties of virgin asphalt, MWR modified asphalt, and KMWR modified asphalt were comparatively studied by the standard segregation test, bending beam rheometer (BBR) test, and dynamic shear rheometer (DSR) test. The effect of composite activation on waste rubber powder particles was studied by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and Brunauer–Emmett–Teller (BET) tests. The main results showed that after the physical and chemical composite activation, the storage stability of waste rubber powder modified asphalt was significantly improved, WR modified asphalt had better crack resistance, better rutting resistance, and better fatigue performance. After physical and chemical activation, WR was desulfurized, and a large number of active groups was grafted on the WR particles.


2020 ◽  
Vol 10 (19) ◽  
pp. 6633
Author(s):  
Jarosław Korus ◽  
Lesław Juszczak ◽  
Mariusz Witczak ◽  
Rafał Ziobro

The aim of the study was to evaluate the use of citrus fiber for the nutritional enrichment and technological improvement of gluten-free bread. A partial replacement of starch in bread formulation was analyzed in terms of the dough’s rheological properties and selected quality parameters of the bread. The results allowed to conclude that the presence of citrus fiber modifies the rheological properties of the dough, causing an increase in storage modulus (G′) and loss modulus (G″) values, as well as zero shear viscosity, accompanied with a decrease in instantaneous compliance (J0) and viscoelastic compliance (J1) to the applied stress, which reflects dough strengthening caused by significantly greater water binding and swelling properties characteristic of this ingredient. The introduction of the citrus fiber to bread formulations caused a significant decrease in bread volume and structure changes in crumb visible in the larger porosity and average pore size. The presence of citrus fiber affected texture, decreasing crumb hardness, springiness, cohesiveness and chewiness in comparison to the control. It could also be observed that the use of citrus fiber results in limited crumb hardening during storage, which indicates that this component could be an effective factor retarding the staling of the gluten-free bread based on starch and hydrocolloids.


2013 ◽  
Vol 14 (3) ◽  
pp. 723-734 ◽  
Author(s):  
Khaldoun M. Shatanawi ◽  
Szabolcs Biro ◽  
Mohammad Naser ◽  
Serji N. Amirkhanian

2018 ◽  
Vol 913 ◽  
pp. 1045-1053 ◽  
Author(s):  
Hao Chen ◽  
Shao Peng Wu ◽  
Gang Liu ◽  
Yong Jie Xue

In this study, three typical tires from bicycles, passenger-cars and trucks were collected and ground into crumb rubber modifiers (CRM) with different particle sizes to modify the asphalt binder. The composition and surface morphology of the three CRMs were analyzed by thermogravimetric analysis (TG-MS) and scanning electron microscopy (SEM). The rheological properties of the binder were evaluated using a dynamic shear rheometer (DSR) and a bending rheometer (BBR). The results show that the main rubber compositions in the bicycle tire (B), the passenger tire (P) and the truck tire (T) are butyl rubber (IIR), styrene-butadiene rubber (SBR) and natural rubber (NR), respectively. Adding CRMs improve rheological properties of base binder. Due to the differences between the composition and the structure, the rheological properties of the P CRM and T CRM containing more SBR and more NR are better at high temperatures and lower temperatures, respectively. And finally the CRM resources and particle size determine the rheological properties of modification effect of base binder. The results can be used to guide the classification and disposal of waste tires. According to the expected modification effect of the asphalt binder, the productions of asphalt pavement construction are enhanced by the high quality products of CRMs.


2012 ◽  
Vol 39 (10) ◽  
pp. 1125-1135 ◽  
Author(s):  
Hainian Wang ◽  
Zhanping You ◽  
Shu Wei Goh ◽  
Peiwen Hao ◽  
Xiaoming Huang

Crumb rubber is the recycled rubber particle obtained from mechanical shearing or grinding scrap tires into small particle sizes less than 6.3 mm (or approximately 1/4”). The rheological properties of asphalt binder have an important effect on the field performance of asphalt mixtures and the long-term serviceability of asphalt pavement. The objective of this research is to evaluate the high temperature rheological performance of rubber asphalt binder based on the complex shear modulus (|G*|) and the phase angle (δ) values using the dynamic shear rheometer. Five rubber asphalt dosages at 0, 10, 15, 20, and 25% by weight of asphalt (Superpave PG 64-22), respectively, were used to modify asphalt binder; and three rubber particle meshes, 20#, 30#, and 40#, were utilized in this research. The |G*| at various temperatures and frequencies were tested on each sample, including original and short-term aging binder using the rolling thin-film over. The master curves of |G*|/sin(δ) for each type of rubber asphalt was generated to investigate its rheological properties over a broad range of temperatures and frequencies. Based on the testing results, it was found that the addition of crumb rubber significantly increases the |G*| of asphalt binder, which is desirable to potentially improve the anti-rutting performance of asphalt mixtures. It was also found that the addition of 10% mesh crumb rubbers bumps up the high temperature grade of asphalt, from PG64 to PG76 in this case. The master curve using the |G*|/sin(δ) of rubber asphalt shows a substantial improvement in rutting resistant at each testing temperature and loading frequency. However, it was noteworthy that the rutting resistance enhancement of crumb rubber was affected by the percentage of rubber used, the rubber particle size and its aging condition.


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