Laboratory Investigation of Rubberized Asphalt Using High-Content Rubber Powder

Abstract

Rubberized asphalt (RA) has been successfully applied in road engineering due to its excellent performance; however, the most widely used rubber content is about 20%.To improve the content of waste rubber and ensure its performance, seven rubberized asphalts with different powder content were prepared by high-speed shearing. Firstly, penetration, softening point, and ductility tests were carried out to investigate the conventional physical features of high-content rubberized asphalt (HCRA). Then, the dynamic shear rheometer test (DSR) was conducted to estimate the high-temperature rheological properties. The bending beam rheometer test (BBR) was carried out to evaluate the low-temperature rheological performance. Finally, combined with the macroscopic performance test, the modification mechanism was revealed by the Fourier transform infrared reflection (FTIR) test, and scanning electron microscope (SEM) analysis was used to observe the microscopic appearance before and after aging. The results show that rubberized asphalt has excellent properties in high- and low-temperature conditions, and fatigue resistance is also outstanding compared with neat asphalt. As the crumb rubber content increases, it is evident that the 40% RA performance is the best. The low-temperature properties of HCRA are better than the traditional 20% rubberized asphalt. This study provides a full test foundation for the efficient utilization of HCRA in road engineering.

A Review of Rubberised Asphalt for Flexible Pavement Applications: Production, Content, Performance, Motivations and Future Directions

“…The scanning electron microscope (SEM) imaging revealed that the high concentrations of CR powder created an excellent network connection with virgin asphalt. The microscopy of asphalt with high rubber contents showed minor differences before and after ageing, and the compatibility and stability remained satisfactory even after extended ageing [26].…”

“…Tables 3-5 show that adding less than 20% CR enhanced the performance of CR-modified asphalts. In contrast, high rubberised asphalt contents of 20-50% imparted excellent high-temperature characteristics, low-temperature properties and fatigue resistance compared to virgin asphalt [26]. Figure 4 shows crumb rubber with varying particle sizes.…”

“…The environmental scanning electron microscope (ESEM) analysis showed no apparent difference between the CR particles, although the surface of the treated CR particles was more porous and open. The chemical activation improves the interaction with the asphalt binder [26]. The AFM images in Figure 6 show asphalt binders with varying percentages of crumb rubber powder and the characteristic changes in the catana phase.…”

Comparative Study on the Dynamic Response of Asphalt Pavement Structures: Analysis Using the Classic Kelvin, Maxwell, and Three-Parameter Solid Models

“…For rubberized asphalt, a rubber powder content of over 25% can become a high-content rubberized asphalt, and a large amount of research has proven the feasibility of high-content rubberized asphalt [11,12]. In recent years, it has been found that highcontent rubberized asphalt (HCRA) has better performance in terms of high-temperature rutting resistance and fracture resistance compared to ordinary RA [13,14]. Also, its asphalt mixtures have good rutting and fatigue resistance [15][16][17][18].…”

Aging Potential and its Impact on the Bonding Strength of Rubberized RAP Asphalt Binder

“…The impacts of CR and RAP binder modifications on the rheological characteristics were also investigated. Multiple studies showed that CR-modified binder (CRMB) has a lower phase angle (δ), higher shear modulus ( G *), higher rutting factor ( G */sin­(δ)), lower creep stiffness, and lower nonrecoverable strain after multiple stress–strain recovery cycles (MSCR) than virgin binders. − Roja et al investigated the rheological characteristics of RAP binder mixed with a virgin binder (VRAPB), and they revealed that fatigue life and creep compliance significantly decrease while the rutting factor increases by elevating the RAP binder dosage . However, the binder behavior significantly changes by mixing the RAP binder with CRMB, where the binder performance does not show a consistent trend by changing the RAP binder or CR dosages.…”