Conventional, Thermal, and Rheological Properties of Asphalt Binder Modified by Carbon Nanotubes and Crumb Rubber

Author(s):  
Yumei Liu ◽  
Mulian Zheng ◽  
Xia Liu ◽  
Fei Wang ◽  
Shan Liu
2021 ◽  
Vol 902 ◽  
pp. 135-143
Author(s):  
Mohammad Ali Khasawneh ◽  
Khalid Ghuzlan ◽  
Nada Bani Melhem

Rutting, fatigue cracking and low temperature cracking are the most important distresses in asphalt pavements as a result of changes in rheological properties of asphalt binder. Many types of modifiers were used to enhance asphalt behavior at both low and high temperatures. In this study, carbon nanotubes (CNT) were used as one of many nanomaterials that take a large attention in the latest research related to asphalt modification against different types of distresses. Effect of CNT on rheological properties of asphalt binder was investigated by testing unmodified and CNT modified asphalt binders using two of Superpave devices: Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR). Penetration, softening point, flash point and rotational viscosity (RV) tests were carried out as well. CNT was added in 0.1%, 0.5% and 1% by weight of asphalt binder. It was found that adding CNT in 0.5% and 1% increase stiffness of asphalt and consequently asphalt pavement rutting resistance. On the other hand, this increase in stiffness affected pavement behavior adversely which is not desirable for fatigue and low temperature cracking. However, Superpave specifications were still satisfied and asphalt binder’s relaxation properties were improved upon CNT modification. It was eventually found that 0.5% of CNT is the optimum percentage for the best performance.


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.


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):  
Eslam Deef-Allah ◽  
Magdy Abdelrahman

Asphalt binder modification by crumb rubber modifier (CRM) could enhance its rheological properties at high and intermediate temperatures by increasing its stiffness and elasticity. To obtain a modified binder blend with more enhanced intermediate- and low-temperature rheological properties, used motor oil (UMO) was introduced to the crumb rubber-modified asphalt (CRMA) binder. The enhanced high- and intermediate-temperature rheological properties of the modified binders were investigated using a temperature sweep test. UMO, used as a rejuvenator, can regulate the CRM role in the modified binder blend by creating a balance between the binder’s enhanced stiffness and fluidity. This was achieved by increasing |G*|/sin δ at high temperatures and decreasing |G*|.sin δ at intermediate temperatures. The mutual components between the CRM and the asphalt binder were explored by thermogravimetric analysis and Fourier transform infrared (FTIR) spectroscopy. UMO was found to have similar FTIR bands of the asphalt binder that helped the CRM particles to absorb more low-molecular-weight fractions at the beginning of the interaction time, which caused them to swell more and then dissolve, releasing their polymeric components in the asphalt binder’s liquid phase. Adding UMO with two and half percentage by the weight of the neat asphalt binder to the CRMA binder, interacted at 190°C–50 Hz–60 min, could increase the CRM dissolution and cause a greater release of CRM polymeric components into the asphalt binder matrix. This was assured by the presence of FTIR peaks at 911 and 966 cm−1 that are related to the polybutadiene, synthetic rubber in CRM.


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