The solar photovoltaic (PV) power generation system (PGS) is a viable alternative to fossil fuels for the provision of power for infrastructure and vehicles, reducing greenhouse gas emissions and enhancing the sustainability of road transport systems. A highway slope is generally an idle public area with high accessibility, which is the ideal application scenario for a PV PGS. The assessment of PV power generation potential (PGP) is key for the planning and design of PV PGS projects. Previous approaches to potential assessments are mainly based on digital maps and image processing techniques, which do not fully consider the impacts of the highway orientation, the slope geometric characteristics, and the PV panel placement scheme on the evaluation results. Therefore, this study proposes an assessment method for the PV PGP on highway slopes using the design or calculated highway and slope geometric parameters and the solar radiation received by PV panels under the desirable placement scheme. Highway segmentation and geometric parameter calculation methods were established, and the optimal PV array placement schemes for typical slope orientations were determined by simulating the PV power generation in the software PVsyst (version 7.2). Afterwards, the theoretical PGP could be calculated using the received solar radiation and the available slope area. By subtracting the energy loss caused by temperature changes, the operation of inverters, and the PV modules’ performance decay, the actual PV PGP could be obtained. Finally, a case study of the solar PGP assessment of a 1.97 km long highway section is provided, and the feasibility of the proposed method is verified.

This study investigates the establishment and calibration method of the rut depth (RD) prediction model of inverted asphalt pavements (IAPs), based on full-scale accelerated pavement testing (APT), which facilitates the accurate and reliable design or maintenance of IAPs. A power function is adopted for the prediction model construction of the rut progression before the failure stage, based on the typical permanent deformation progression curve of flexible pavements. The APT loading history is divided into units, according to the difference in physical conditions, providing the basis for a cumulative RD analysis and model calibration. The nonlinear incremental recursive (IR) principle is applied in the RD analysis to consider the influence of the nonlinear material property, performance deterioration, and loading history on the RD development. Further, the rut shift function relating prediction models obtained from laboratory tests and full-scale APT is established to introduce the APT data in the calibration process. Accordingly, the mechanistic-empirical RD prediction model calibration method, based on APT and the IR principle, is proposed and applied in a case study of a IAP RD prediction model calibration. Four 3.5 m × 4 m IAP test sections S1–S4 are constructed and instrumented and 700,000- and 900,000-wheel loads are applied on test sections S1–S2 and S3–S4, respectively, using the heavy vehicle simulator. The test data from the different APT load units are utilized for the model calibration, and the resultant prediction errors range from −2.16 mm to 1.18 mm. The calibrated model can also be used for the RD prediction of IAPs with other design schemes, by updating the corresponding material-related coefficients and the finite element model, which is essential for the design and maintenance of IAPs. The proposed calibration method could be a useful reference for the establishment of flexible pavement performance prediction models.

The increasing number of waste rubber tires has attracted the attention of more and more researchers. Rubber asphalt has better performance compared with original asphalt. However, the compatibility between rubber powder and asphalt is poor because of the difference in physical and chemical properties and the improvement of high-temperature performance of asphalt by rubber powder is very limited. The compatibility between rubber powder and original asphalt plays a key role in the storage stability and rheological performance of rubber asphalt. This paper provides a comprehensive overview of rubber asphalt, factors influencing compatibility, compatibility evaluation methods, and improvement approaches. Desired compatibility results from the fact that rubber powder is cross-linked with molecules of original asphalt and evenly distributed in the original asphalt, forming a homogeneous system. Starting from the preparation process of rubber asphalt, the best preparation process was summarized. Then the activity of rubber powder is improved by physical and chemical methods, or other additives are added to finally promote the formation of a cross-linking network structure between rubber powder and original asphalt. Rheological method is the most widely used method in compatibility evaluation, but it is gradually accepted by researchers to evaluate the compatibility by observing the molecular morphology of rubber asphalt.