Property improvement of thermosetting natural rubber asphalt binder by mineral oil

Abstract

To achieve environmental sustainability, a new type of thermosetting binder, namely thermosetting natural rubber asphalt binder (TNRA), was prepared using natural rubber. However, TNRA has some limitations such as poor compatibility, high initial viscosity, and insufficient flexibility, which require improvement. Mineral oil, a clean additive derived from petroleum fractionation products, has great potential for solving these problems associated with TNRA. This study aims to investigate the effect of mineral oil on TNRA compatibility, as well as its impact on workability, thermal stability, and mechanical properties. Experimental results demonstrate that mineral oil can enhance the compatibility of natural rubber-modified asphalt (NRMA), with aromatic oil playing a more significant role. Improving compatibility leads to improved flexibility of the cured NRMA (that is, TNRA). Furthermore, by balancing the effects of mineral oil on these properties, it is suggested that the ideal dosages of mineral oil are 1.5 times those of natural rubber latex. Finally, the mechanism of improving TNRA properties by mineral oil is explained from the perspective of asphalt colloid structure. The assumption of asphalt heterogeneous equilibrium colloidal structure provided in this study has been confirmed by experiments, and it is feasible to improve the compatibility of other polymer-modified asphalts by selecting light substances, such as mineral oil.