The floating photovoltaic (FPV) array, which consists of tens or hundreds of rows of floating photovoltaic systems, exhibits great economic and environmental benefits. An FPV array arranged in the ocean will be subjected to the combined action of wind, waves, and currents during the installation, service, and maintenance processes; however, systematic research in this field is still lacking. As a representative of the FPV array, this study on the hydrodynamic characteristics of a single-row FPV system is a fundamental prerequisite for the safe design of large-scale FPV arrays in the near future. In this paper, based on the potential theory, a numerical model of a single-row FPV system with ten floating platforms is established with ANSYS-AQWA software. Following this, the hydrodynamic coefficients of a single floating platform are calculated and evaluated. After that, the dynamic responses of the FPV system under different load combinations are explored. Finally, the influence mechanism of wave parameters on the hydrodynamic characteristics of the FPV system is discussed in detail, including the wavelength and wave height. The results indicate that, within the scope of this study, the floating platforms have good seakeeping and stability. The wave load dominates for all conditions, and the presence of the current will affect the parameters of the wave. In addition, the relative relationship between the wavelength and the length of FPV system will affect their resonance effect, and the increase in wave height will significantly enhance the dynamic response of the FPV system. This study can help to provide references for the safety design of FPV arrays.

In order to study the adhesion properties of fast-melting SBS-modified asphalt (SBS-T) at the interface with aggregates, the contact angles of three dosages of SBS-T asphalt with three liquids (distilled water, glycerol, and formamide) were determined by the sessile drop method based on surface free energy theory. The evaluation indexes such as cohesion, asphalt–aggregate adhesion, stripping work and energy ratio of the asphalt were analyzed and the adhesion properties of the asphalt–aggregate system were investigated with the help of micromechanical methods. The results indicate that SBS-T can improve the adhesion properties of the asphalt. Furthermore, as the dosage of the modifier increases, the cohesion work, adhesion work, and energy ratio of the SBS-T asphalt exhibit a similar rise. As the spalling work reduces and the adhesion between asphalt and aggregate improves, it is noteworthy that the SBS-T asphalt–aggregate system exhibits superior adhesion performance compared to the SBS-modified asphalt–aggregate system, despite the same dosage.

Geopolymer materials have several obvious advantages such as energy conservation, emission reduction, and waste reuse, so they can become substitutes for cement materials. In this study, geopolymer mortars made from blast furnace slag and steel slag reinforced by basalt fibre and polyvinyl alcohol (PVA) fibre were prepared to explore the effect on their strength and shrinkage properties. Scanning electron microscopy (SEM) was employed to characterize the reaction mechanism of the geopolymer mortars. The results show that both PVA fibre and basalt fibre can improve the mechanical properties of geopolymer mortars during the late curing period. The geopolymer reinforced by basalt fibre manifested a better toughness. A proper content of PVA fibres and basalt fibres can effectively reduce the drying and autogenous shrinkage of geopolymer mortars. The optimal content of basalt fibres and PVA fibres to reduce the drying shrinkage was 0.4%. The SEM results show that the fibres can effectively alleviate the stress concentration and prevent crack propagation.

Reflective cracking is one of the major forms of deterioration in semi-rigid base asphalt pavements. It is, therefore, very important to have a correct understanding of the internal crack propagation mechanism of asphalt pavement to propose the most effective remedial solution(s), which corresponds to that mode of failure. In this study, two-dimensional asphalt pavement layered models are first established by modifying the peridynamics theory. Then, the influence of asphalt overlay thickness and load form on reflective crack propagation is explored. On this basis, the influence of friction between the tire and road surface on reflective crack propagation is analyzed. The results show that increasing the thickness of the asphalt overlay can inhibit reflective crack propagation, and the friction force accelerates reflective crack propagation when the direction of friction is the same as that of reflective crack propagation; otherwise, it inhibits reflective crack propagation. Additionally, the most unfavorable load position is the asymmetrical load when the vehicle is far from the reflective crack.

The substitution of slag-based geopolymer materials for cement-stabilized macadam in road bases is in line with the demand for green and sustainable development in the transportation industry. Thus, slag/fly-ash-based geopolymer materials were prepared to stabilize macadam of road bases in this study. The mechanical properties, freeze-thaw resistance, and dry shrinkage durability of slag/fly-ash-based stabilized macadam materials were studied to analyze the influence of geopolymer dosage on these properties of stabilized macadam. Microscopic tests such as XRD, FITR, and SEM were carried out to explore the formation mechanism of strength and the characteristic of interface transition zone (ITZ). Results show that the 28 d compressive strength, compressive elastic modulus, and tensile strength of slag/fly-ash-based stabilized macadam increase linearly with the increase of geopolymer content. When the dosage of slag-based geopolymer is 4%, the 7 d unconfined compressive strength of slag/fly-ash-based stabilized macadam reaches 8.76 MPa, and the strength still reaches 14.84 MPa after five freeze-thaw cycles (28 d), which satisfy the application requirements of expressway and first-class highway base (JTG/T F20-2015). The dry shrinkage property of slag/fly-ash-based stabilized macadam is better than that of cement-fly-ash-stabilized macadam. When the amount of geopolymer is 3%, the dry shrinkage strain of slag/fly-ash-based stabilized macadam is 231.2 με, which is smaller than that of cement-fly-ash-stabilized macadam (261.3 με). No obvious porosity around the ITZ was detected, indicating good binding between the geopolymer and the aggregate.

In this study, two kinds of quick melting modifier SBS-T and SBS-W, as well as the traditional SBS modifier, were used in the optimization design of asphalt binders. The changes in material structure and fatigue properties of three polymer-modified asphalt after adding 3% Sasobit to warm mix agent were investigated. The feasibility of SBS-T and SBS-W in asphalt binder was discussed from the modification mechanism and fatigue properties. In order to reveal the modification mechanism, the interaction mechanism between the fast-melting SBS modifier and the base asphalt was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The temperature sensitivity and viscoelastic properties of SBS-T and SBS-W modified binders were determined by frequency scanning (FS). The fatigue properties of SBS-T and SBS-W modified binders were tested by linear amplitude scanning (LAS). The results of FTIR showed that there was no chemical reaction between the SBS-T and SBS-W and the base asphalt. XRD results showed that SBS-W-modified asphalt has stronger fluidity. The results of FS and LAS showed that the asphalt binder with Sasobit has good stiffness and elastic recovery ability, and the same SBS-T and SBS-W have better temperature sensitivity and deformation resistance. In addition, the fatigue life of asphalt binder under the linear viscoelastic continuous damage theory is increased 3.9 times by SBS-W.