In this study, the novel nanomaterial graphene oxide (GO) was added as a modifier to polyurethane–styrene-butadiene-styrene (SBS)-modified asphalt, and a graphene oxide/polyurethane/SBS composite-modified asphalt mix was prepared. The effect of the graphene oxide material on the low-temperature crack resistance of the asphalt and mixes was investigated by bending beam rheometer (BBR) tests, beamlet bending tests at different low temperatures, and characterization by scanning electron microscopy for its microscopic condition. OpenCV image processing was used to visually represent the low-temperature cracking of the mix. The results of the BBR tests showed that the incorporation of graphene oxide resulted in a reduction in creep stiffness S and an increase in creep rate m compared with the control asphalt. The best improvement in the low-temperature cracking resistance of the polyurethane/SBS-modified asphalt was achieved at 0.5% GO doping. The results of the small beam flexural tests showed that graphene oxide as a modifier improved the flexural strength and flexural strain of the mix, resulting in a mix with a lower stiffness modulus and a better relaxation stress capacity with the addition of graphene oxide, which is also expressed through the OpenCV images. Graphene oxide significantly improved the low-temperature crack resistance of polyurethane-SBS-modified asphalt and its mixes. As a new type of nanomaterial-modified asphalt, graphene oxide/polyurethane/SBS composite-modified asphalt shows promising applicability in cold zone roads.

In order to clarify the effect of the new nano-material graphene oxide on the performance of Polyurethane-SBS modified asphalt and asphalt mixture under the effect of thermal aging, the cracking process of semicircular bending test (SCB) specimens was monitored in situ based on computer vision image processing technology (OpenCV), and the modified asphalt and the cracking characteristics of the modified asphalt and mixture were further analyzed by the tests of semicircular three-point bending and aggregate contact angle measurement. The test results showed that the thermal aging effect severely damaged the composite structure formed by the cross-linking effect of Polyurethane and SBS modifier in asphalt, which intensified the degradation of Polyurethane and SBS modifier and led to great changes in the rheological properties of asphalt after aging. However, the incorporation of the new nanomaterial Graphene oxide can slow down the degradation of Polyurethane and SBS modifiers and the change of asphalt cross-linked composite structure, making the anti-cracking and anti-aging properties of Graphene oxide-Polyurethane-SBS modified asphalt mixes better than those of Polyurethane-SBS modified asphalt mixes. Therefore, the new nano-material graphene oxide added to Polyurethane-SBS modified asphalt is meaningful and feasible. Graphene oxide-polyurethane-sbs composite modified asphalt, as a new nano-material modified asphalt, is stronger against the ultraviolet and light asphalt that is prone to aging. With regards to improving the application of road projects, the results are very promising.

A real rejuvenator must have the ability to disaggregate oxidized asphaltene nanoclusters. However, few studies pay attention to the topic, and there is a lack of comparison of the disaggregation ability of different rejuvenators. Thus, the disaggregation ability and regeneration mechanism of three bio-rejuvenators (waste cooking oil (WCO), waste wood oil (WWO), and straw liquefied residue oil (SLRO)) on oxidized asphaltene nanoclusters were studied in this paper. Laboratory tests and molecular dynamics (MD) simulation were used to compare the effectiveness of the three bio-rejuvenators and reveal its corresponding mechanism. It is found that these bio-rejuvenators have a softening effect on aged asphalt binder, but not all of them can disaggregate oxidized asphaltene nanoclusters. The introduction of WWO and WCO can effectively disturb the nanoclusters caused by the increase of polar functional groups during the oxidation process. The effect of WWO is more significant, but neither of them can restore the asphaltene dispersion to the virgin asphalt binder. SLRO has an adverse effect on the disaggregation of oxidized asphaltene nanoclusters. WCO, WWO, and SLRO showed different disaggregation mechanisms, including ″pull-out, intercalation, and compression″, respectively. WCO and WWO can increase the activation energy reduced by aging in a short aging time, and SLRO makes the activation energy lower. Such findings can help enterprises screen more reasonable rejuvenators to facilitate the recycling of reclaimed asphalt pavement (RAP) materials and promote the sustainable development of the construction industry.

In order to study the high and low temperature properties, and fatigue properties, of silica fume/SBS (Styrene-Butadiene-Styrene) compound modified asphalt (SFSCMA), dynamic shear rheometer (DSR) and bending beam rheometer (BBR) are used to study matrix asphalt (MA), silica fume modified asphalt (SFMA) (silica fume (SF) 6%), SBS modified asphalt (SBSMA) (mass ratio of SBS to Matrix asphalt 4%), and silica fume/SBS compound modified asphalt, and the high temperature rheological properties of silica fume/SBS compound modified asphalt with different silica fume additions are also studied. The modification mechanism of SFSCMA was studied by scanning electron microscope (SEM). The investigation results turn out: along with the increase in the content of SF, the high temperature performance of SFSCMA is improved significantly. When the content of SF is 6%, the high temperature performance is the best. When the content of SF is more than 6%, the high temperature property of SFSCMA is lower than that of SBSMA. It is suggested to choose 6% as the content of SF. Compared with MA, SFMA, and SBSMA, SFSCMA has excellent high temperature performance; compared with MA and SFMA, the low temperature performance of SFSCMA is improved, but it is worse than that of SBSMA. Moreover, when the temperature is lower than −30 °C, its low temperature performance is close to that of MA, or even worse than that of MA. After the compound modification of SF and SBSMA, the fatigue properties of the asphalt are improved, and the fatigue performance of SFSCMA is the best among the four kinds of asphalt. There is a cross-linking force in the network structure of SFSCMA, which restrains the flow of the whole system, so that the stability of the compound modified asphalt is significantly improved, which is favorable to the high temperature performance and fatigue resistance of the compound modified asphalt. However, due to its low mobility, it has a negative impact on the low temperature performance of the compound modified asphalt. In addition, according to previous studies, compared with diatomite, it is proven that SF can reach the same level as diatomite in improving the high temperature performance and fatigue performance of asphalt. Therefore, SF can be used as a good choice of asphalt modifier and can achieve the purpose of waste recycling and environmental protection.

In this work, waste polyethylene (PE)-modified 90# asphalt was made in order to investigate the performance of waste polyethylene-modified high-grade asphalt and the optimal blending quantity. Dynamic Shear Rheology (DSR) and Bending Beam Rheometer (BBR) tests were used to evaluate the high- and low-temperature performance of modified 90# PE-modified asphalt. Infrared spectroscopy and fluorescence microscopy were used to investigate the modification process and distribution status of waste PE in 90# asphalt. The DSR and BBR tests revealed that waste PE enhanced the high-temperature performance of 90# base asphalt and that 5% was the best blending rate. However, the change affects asphalt’s low-temperature performance, and the negative effect on asphalt’s low-temperature performance was minimized at 1% dosing. The incorporation of waste PE absorbed the light components of asphalt, while waste PE can form a reticulated structure in asphalt, which improves its high-temperature performance but degrades its low-temperature performance, according to the results of infrared spectroscopy and fluorescence microscopy.