This study aimed to investigate variations and relationships between molecular components and rheological properties during the long-term aging of SBS-modified asphalt by the action of moisture. The chemical components and changes in molecular weight during aqueous PAV aging were observed using a four-component test and GPC test, and these morphological changes were quantified. Viscosity tests, time-scan tests and damage-healing tests were carried out to investigate the rheological properties during the aging process. Finally, the mechanism of asphalt aging under the influence of moisture was discussed. The results showed that moisture facilitated the long-term aging of asphalt and complicated the aging behavior under pressure-aging conditions. The dissolution of certain hydrophilic groups may be responsible for the decrease in resin content. The fatigue and self-healing properties of asphalt were weakened by moisture during the aging process. This was mainly attributed to a decrease in the composition of the asphalt colloidal dispersion medium, which resulted in earlier and faster development of microcracks under repeated loading as well as retardation in the rate of asphalt surface approach, wetting and spreading. Under long-term aging in the presence of moisture, the molecular components of the asphalt showed significant correlations with the rheological properties. The results of this study can contribute to further explaining the influence of moisture on the thermal-oxidative aging of asphalt.

In order to study the influence of corrosion rate and shear span ratio on reinforced concrete beam, a numerical analysis method of corroded reinforced concrete beam was put forward. Bond‐slip relationship formula between reinforcement and concrete was suggested. A three‐dimensional finite element model of corroded reinforced concrete beam was established. Calculation method of ultimate bearing capacity for reinforced concrete beam was suggested. Ultimate bearing capacity experiment on 14 corroded reinforced concrete beams with different corrosion rates and shear span ratios was carried out. Numerical analysis results and experimental results were compared and analyzed. The results show that, for reinforced concrete beams with different corrosion rates and shear span ratios, load‐deflection curve can be divided into elasticity stage and plasticity stage. With the increase of corrosion rate and shear span ratio, ultimate bearing capacity of corroded reinforced concrete beam decreased. When shear span ratio was 3.0, if corrosion rate increased by 1%, experimental value of ultimate bearing capacity decreased by 1.002 kN. When shear span ratio was 2.4, if corrosion rate increased by 1%, experimental value of ultimate bearing capacity decreased by 1.849 kN. The numerical analysis method put forward in this paper was feasible, and the suggested ultimate bearing capacity calculation method for reinforced concrete beam has a high accuracy.

Concrete-filled steel tube (CFST) widely applied in engineering structures due to its superior behavior requires monitoring and assessment for damage level. Here, the acoustic emission (AE) technique was used to monitor the fracture process of concrete core in CFST stub columns subjected to axial compression. Test and analyzed results show that the damage process of CFST specimens can be divided into four stages: compaction, elastic-plastic stage, strengthening and secondary strengthening. In the elastic-plastic stage, the evolutionary features of the AE event rate, cumulative energy, Ib-value and crack classification are capable of providing an early warning for cracked concrete core. Full crack propagation can be identified by the rapid increase in the proportion of shear cracks near the inflection point of load, which is impermissible in engineering structures. According to the analyses of the AE event rate and signal intensity in the elastic-plastic stage, the confinement of steel tube with thicker wall thickness or higher strength is delayed, which implies that this confinement is suggested to be triggered early. It is indicated that the AE technique has the potential to monitor and evaluate the damage process of CFST stub columns under axial compression, which can provide additional insight into the failure mechanism and assist in the scheme of repairs.

This paper aims to reveal the degradation of the flexural load capacity of reinforced concrete (RC) beams reinforced with aluminum alloy (AA) under atmospheric conditions. For the same, first, time-varying models of the flexural load capacity of RC beams were developed before and after reinforcement with AA and steel plate based on the time-varying properties of the materials. Subsequently, upon collecting existing test data, the reliability of the models was verified. Finally, the parameters of AA-reinforced and steel plate-reinforced RC beams were analyzed to investigate the influence of factors such as concrete cover depth, cross-sectional area of reinforcing material, and cooperative working coefficient of reinforcing material and concrete (demonstrate the ability of reinforcement material and concrete to work together) on the remaining service life, rust initiation time, and cracking time. The results show that under atmospheric environment, the flexural time-varying degradation model for RC beam can be divided into three stages: pre-rusting, rusting-pre-cracking, and post-cracking, with differences in the dominant factors at each stage. In terms of long-term performance, AA reinforcement is significantly more efficient than steel plate reinforcement. This study provides some theoretical basis for the design of AA reinforcement in the atmospheric environment.

In order to simplify the completion process of cable force optimization and adjustment in long‐span concrete‐filled steel tube arch bridges, a new method was proposed in the present study. To this end, a reasonable completion cable force calculation method was proposed based on the influence matrix principle of cable force optimization. Then combined with the mechanical characteristics of concrete‐filled steel tube arch bridge, the weighted matrix was introduced to simplify the influence matrix of cable force and optimize the suspender cable force. The performed comparative study showed that the maximum difference of single cable force between the measured and calculated values is less than 5%, and the calculation error satisfies the requirements of the specification. It is concluded that the proposed method can accurately control the suspender tension construction in the arch bridge, optimize the cable force of long‐span concrete filled‐steel tube arch bridge, and realize the comparison and selection of various optimization schemes. The research results have been successfully applied to the suspender force adjustment of Third Pingnan Bridge, which greatly simplifies the adjustment steps and the total cable force difference in the whole bridge is 1.37%, the difference between the measured and designed suspender tensions of Heshan Hongshui River Bridge at completion state is less than 2%. The successful application of this method effectively saves the labor and material cost of suspender adjustment and further enhances the superiority of steel tube concrete arch bridge. The proposed method is expected to be an excellent choice to monitor constructions, adjust the bridge completion stage, and provide a reference for the suspender tension construction control of similar bridges.