Experimental Investigation on the Properties of Vulcanized Natural Rubber-Modified Asphalt Binder

With the huge production of natural rubber (NR), it is feasible to produce natural rubber-modified asphalt binder (NRMB) to achieve carbon neutrality and environmental sustainability in asphalt pavement construction. As a solid thermoplastic elastomer, the dispersion and compatibility of NR in the asphalt binder are poor, which is the main obstacle to using these solid thermoplastic elastomers as modifiers. Accordingly, a high-performance vulcanized natural rubber-modified asphalt binder (VNRMB) was prepared by rotational shearing to disperse NR into the asphalt binder, providing the modification scheme of NR and optimizing the performance of the modified binder to be conducive the better durability. First, the best vulcanization scheme was determined by the consistency tests. Then the rheological and low-temperature properties of the asphalt binders were tested by the dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests, respectively. It was found that in high and low temperatures, VNRMB performed significantly better than virgin asphalt binder (VB) and NRMB. The high-temperature deformation resistance and low-temperature cracking resistance for 2.5/10VNRMB were significantly better than those of 2.5NRMB and VB, apart from the lower thermal sensitivity, the better elastic recovery, and storage stability. Fluorescence microscopy (FM) and Fourier transform infrared spectroscopy (FT-IR) tests indicated that NR dispersed in the binder was cross-linked by the sulfur to form a network structure in VNRMB.

Automated summary

By dispersing natural rubber into asphalt through rotational shearing, a high-performance vulcanized natural rubber-modified asphalt binder (VNRMB) was prepared, which showed improved high-temperature deformation resistance and low-temperature cracking resistance compared to the virgin asphalt binder and natural rubber-modified asphalt binder.