Through laboratory testing, this research studied the connection between air-void structures of hardened concrete and fresh concrete and discussed the effects of the air-void structure on the salt-frost durability of the concrete. The results demonstrate that, in comparison with fresh concrete, the air-void spacing factor shows a close correlation with hardened concrete air-content and decreases in the form of a power function as the air-content increases. When the fresh concrete air-content is more than 6% and the hardened concrete air-void spacing factor is less than 0.18 mm, the influence of parameters of air-void structure on the salt-frost resistance of the concrete reduces. The air-void spacing factor more significantly affects the salt-frost resistance of the concrete compared with air content and the correlation reaches 0.93. Therefore, air-content and air-void spacing factor are recommended for dual control.

Fatigue cracks are main damages to steel bridge deck pavement with thermosetting epoxy asphalt. By combining a high-toughness resin material with fiber woven fabrics, this study formed an ultrathin overlay of fiber-reinforced high-toughness resin to improve cracking resistance of pavement. Through theoretical measurement and bending test, this research studied change laws of bending and tensile properties of epoxy asphalt concrete after fiber reinforcement and analyzed bending strength and the maximum failure strain of beams at different temperatures. Moreover, the reinforcing effects of different fibers were discussed. It is found that bending strength, maximum failure strain, and stiffness modulus of the beams with epoxy asphalt are improved after fiber reinforcement. With the decrease of temperature, after fiber reinforcement, the mode of bending failure of the epoxy asphalt mixture (EAM) changes from brittle fracture into shear failure, accompanied with significant yield phenomenon. Furthermore, organic carbon fiber is sensitive to influences of temperature, while glass fiber is least sensitive to temperature.

Asphalt pavements are widely used in airports due to their excellent skid resistance, vibration damping, and ease of construction. However, traditional fog seal materials often suffer from insufficient adhesion between fine sand and the emulsified asphalt binder, resulting in limited durability of the maintenance effect. This study aims to optimize the design of traditional fog seal materials and systematically evaluate their surface and durability performance. Firstly, a composite modified emulsified asphalt was prepared as the sand suspension slurry for the sand-containing fog seal. Through the dry wheel abrasion test, the optimal fine aggregates content was determined for four different spraying amounts (0.8, 0.9, 1.0, and 1.1 kg/m²). When the proportion of fine aggregates increases, the spraying amount needs to be increased accordingly to ensure the wrapping effect. Subsequently, pavement performance evaluation was conducted based on several indicators, including surface curing time, British Pendulum Number (BPN) friction coefficient, permeability coefficient, and mass loss rate. The results showed that the designed sand-containing fog seal significantly reduced surface curing time and exhibited superior skid resistance and permeability property compared to styrene-butadiene rubber (SBR)-modified emulsified asphalt. After freeze–thaw cycles, the maximum decrease in friction coefficient was 10.2%, and the mass loss rate after abrasion was approximately 67%, which were lower than those of SBR-modified emulsified asphalt (22.2% and 81%, respectively). Finally, considering the comprehensive performance comparison and evaluation, the optimal mix proportion was determined as 1.0 kg/m² spraying amount with 30% fine aggregates content. The findings of this study provide practical support for improving the durability and service life of airport asphalt pavements.

In recent years, fatigue cracking in orthotropic steel bridge deck pavements has become a significant concern, so the investigation of the mechanical response of the pavement layer has become a central focus in pavement structure design. This experiment subjected a full-scale specimen to a constant amplitude dynamic load of 60 kN to 300 kN over 2 million cycles. Throughout the testing, a circulating water bath elevated the temperature of the pavement layer from 15 °C to 50 °C. Key locations were monitored for strain and deflection data, facilitating an investigation into the mechanical response of the epoxy asphalt pavement system under the effects of temperature and load. The results indicate that the maximum transverse strain at the bottom of the steel deck occurs at the U-rib weld aligned with the load center, reaching 190% of the initial loading strain. Meanwhile, the maximum transverse strain on the pavement surface is observed at the U-rib weld adjacent to the loaded area, measuring 167% of the initial strain. The maximum longitudinal strain is lower than the maximum transverse strain. In the load zone, the longitudinal strain between the U-ribs exceeds that at the U-rib weld. Both transverse strain and relative deflection increase as the load intensifies. The relationship between transverse strain and applied load is characterized by an exponential function, while deflection exhibits a cubic relationship with the applied load. Elevated temperatures also contribute to increased transverse strains at both the bottom of the steel deck and the pavement surface, following an exponential trend. Relative deflection is primarily influenced by the applied load and remains relatively unaffected by temperature variations. When accounting for the coupling of load and temperature, the maximum transverse strains at both the bottom of the steel deck and the pavement surface can be modeled as an exponential function of the independent variables: load and temperature.

In order to solve the dusting and rutting problems of hot mix asphalt mixture during construction and operation, rutting test, bending test, Marshall stability test, freeze-thaw splitting test, uniaxial compression dynamic modulus test, overlay test, and four-point bending fatigue life test are applied on WHMM-13 to study the high-temperature stability, low-temperature cracking resistance, water stability, anti-reflection crack performance and fatigue durability in comparison with HMM-13. The results show that, compared to HMM-13, the dynamic stability and dynamic modulus (45 ℃, 10 Hz) of WHMM- 13 are improved by 10.0% and 47% respectively, and the rutting depth is reduced by 27.3%, indicating that the high temperature stability of WHMM-13 has been greatly improved. As for low temperature cracking resistance, the bending failure strain, stiffness modulus, flexural tensile strength and rupture energy of WHMM-13 are slightly lower than those of HMM-13. As for water stability, the residual stability of WHMM-13 in immersion Marshall test is 87.5%, and the splitting strength is 82.3%, both higher than that of HMM-13. As for anti-reflection crack performance, the total tensile rupture energy of WHMM-13 is 2.32 times that of HMM-13, with cracking resistance index (CRI) increased by 25%, which shows that WHMM-13 has better strength, can effectively prevent the crack from spreading and effectively improve the cracking resistance capacity of asphalt pavement. As for fatigue durability, the fatigue life of WHMM-13 is 5.4% lower than that of HMM-13, with bending stiffness modulus and cumulative dissipation energy reduced by 11.3% and 2.8% respectively, indicating that the fatigue durability of WHMM-13 is slightly reduced.