Improving the high-temperature stability and water damage resistance of asphalt pavements has always been a priority. This study proposed a composite high modulus modifier with rock asphalt and nanopolymer as main materials (HRMA) to prepare the high modulus asphalt mixture for their excellent rutting resistance. Moreover, its modification effect and modification mechanism were studied. The effect of HRMA content on the rheological performance of asphalt was investigated using Brookfield rotational viscosity, dynamic shear rheometers (DSR), and bending beam rheometers (BBR). Their modification mechanisms were revealed by Fourier Transformation Infrared Spectroscopy (FTIR). Besides, the properties of the mixtures were studied in various laboratory tests and compared with the 90# asphalt mixture and SBS asphalt mixture. Some of these included the rutting test, the bending test, the Marshall immersion test, and the freeze-thaw indirect tension test. The results indicated that with the increase of HRMA content, the deformation resistance of the asphalt mixture under high-temperature conditions was significantly improved, and the temperature sensitivity was changed. However, the crack resistance of its asphalt mixtures under low temperature was reduced due to the lower ductility of HRMA-modified asphalt. The recommended HRMA content was 21.8% of the asphalt, combining performance and construction cost.

In order to solve the problem of high-value utilization of coal-to-oil residual direct coal liquefaction residual asphalt, it is compounded with SBS and aromatic oil to modify the matrix asphalt, and 9 compounding schemes are designed using orthogonal experimental methods. Dynamic frequency sweep tests using DSR and a simplified Carreau equation model fitted to the complex viscosity to obtain its zero shear viscosity; the creep recovery rate, irrecoverable creep flexibility and irrecoverable creep flexibility difference of each modified asphalt were determined by MSCR at different temperatures and stress levels, and the high temperature rheological properties of 9 composite modified asphalts were evaluated by grey correlation analysis of zero shear viscosity and high temperature rheological parameters. Bending beam rheological experiments were carried out on the aged composite modified asphalt to analyse its low temperature rheological properties based on the viscoelastic parameters and linear fitting of the Burgers model. The results show that: The high temperature deformation resistance of DCLR composite modified asphalt are better than the matrix asphalt, the most influential modifier is SBS, and the higher the dose, the stronger the high temperature deformation resistance. The unrecoverable creep flexibility Jnr3.2 at 70 °C can better respond to the high temperature performance of asphalt, the ratio of 9% DCLR + 4% SBS + 2% aromatic oil DCLR composite modified asphalt with the best high temperature performance. Burgers model can better reflect the creep process of asphalt, DCLR composite modified asphalt has some defects in low temperature performance, the higher the dose of DCLR, the poorer the low temperature performance of the composite modified asphalt. The low temperature sensitivity of DCLR composite modified asphalt has been reduced, low temperature crack resistance has been slightly enhanced.

Geosynthetic interlayer systems are effective techniques to control reflective cracking and have better waterproof performance in damaged asphalt pavements. The interlayer bonding performance is critical to its function. This research investigated the interfacial adhesive property and road performance of asphalt overlay with geotextile interlayer. First, shear damage energy characteristics of geotextile interlayer have been investigated by varying tack coat types (SBS-modified asphalt, virgin asphalt, and emulsified asphalt), application rates (0.3 kg/m2–1.2 kg/m2), spraying times (1–2), upper mixture paving temperature (140°C–180°C), service temperature (5°C–45°C), and soaking time (0 h–96 h). In addition, bending fatigue tests, rutting tests, and semicircular bending tests were carried out to evaluate the comprehensive road performance of the asphalt overlay. The results showed that the interface adhesive property of asphalt overlay with geotextile interlayer using SBS-modified asphalt is best when the application rate is 0.8 kg/m2. The higher paving temperature is beneficial for the geotextile interlayer adhesion performance when the SBS-modified asphalt is sprayed at one time, while the paving temperature has almost no effect when the SBS-modified asphalt is sprayed at two times. The geotextile interlayer adhesion performance is less affected by temperature and more affected by water immersion. Compared with the common asphalt overlay types, the asphalt overlay with geotextile interlayer using SBS-modified asphalt shows better overall performance.