Tunnel lining structures, which are subjected to the combined effects of water and soil pressure as well as a water-rich erosion environment, undergo a corrosion-induced damage and degradation process in the reinforced concrete, gradually leading to structural failure and a significant decline in service performance. By introducing the Cohesive Zone Model (CZM) and the concrete damage plastic model (CDP), a three-dimensional numerical model of the tunnel lining structure in mining method tunnels was established. This model takes into account the multiple effects caused by steel reinforcement corrosion, including the degradation of the reinforcement's performance, the loss of an effective concrete cross section, and the deterioration of the bond between the steel reinforcement and the concrete. Through this model, the deformation, internal forces, damage evolution, and degradation characteristics of the structure under the effects of the surrounding rock water-soil pressure and steel reinforcement corrosion are identified. The simulation results reveal the following: (1) Corrosion leads to a reduction in the stiffness of the lining structure, exacerbating its deformation. For example, under high water pressure conditions, the displacement at the vault of the lining before and after corrosion is 4.31 mm and 7.14 mm, respectively, with an additional displacement increase of 65.7% due to corrosion. (2) The reinforced concrete lining structure, which is affected by the surrounding rock loads and expansion due to steel reinforcement corrosion, experiences progressive degradation, resulting in a redistribution of internal forces within the structure. The overall axial force in the lining slightly increases, while the bending moment at the vault, spandrel, and invert decreases and the bending moment at the hance and arch foot increases. (3) The damage range of the tunnel lining structure continuously increases as corrosion progresses, with significant differences between the surrounding rock side and the free face side. Among the various parts of the lining, the vault exhibits the greatest damage depth and the widest cracks. (4) Water pressure significantly impacts the internal forces and crack width of the lining structure. As the water level drops, both the bending moment and the axial force diminish, while the damage range and crack width increase, with crack width increasing by 15.1% under low water pressure conditions.

Asphalt pavements are subjected to both repeated vehicle loads and erosive deterioration from complicated environments in service. Salt erosion exerts a serious negative impact on the service performance of asphalt pavements in salt-rich areas such as seasonal frozen areas with snow melting and deicing, coastal areas, and saline soils areas. In recent years, the performance evolution of asphalt materials under salt erosion environments has been widely investigated. However, there is a lack of a systematic summary of salt erosion damage for asphalt materials from a multi-scale perspective. The objective in this paper is to review the performance evolution and the damage mechanism of asphalt mixtures and binders under salt erosion environments from a multi-scale perspective. The salt erosion damage and damage mechanism of asphalt mixtures is discussed. The influence of salt categories and erosion modes on the asphalt binder is classified. The salt erosion resistance of different asphalt binders is determined. In addition, the application of microscopic test methods to investigate the salt damage mechanism of asphalt binders is generalized. This review finds that the pavement performance of asphalt mixtures decreased significantly after salt erosion. A good explanation for the salt erosion mechanism of asphalt mixtures can be provided from the perspective of pores, interface adhesion, and asphalt mortar. Salt categories and erosion modes exerted great influences on the rheological performance of asphalt binders. The performance of different asphalt binders showed a remarkable diversity under salt erosion environments. In addition, the evolution of the chemical composition and microscopic morphology of asphalt binders under salt erosion environments can be well characterized by Fourier Infrared Spectroscopy (FTIR), Gel Permeation Chromatography (GPC), and microscopic tests. Finally, the major focus of future research and the challenges that may be encountered are discussed. From this literature review, pore expansion mechanisms differ fundamentally between conventional and salt storage asphalt mixtures. Sulfate ions exhibit stronger erosive effects than chlorides due to their chemical reactivity with asphalt components. Molecular-scale analyses confirm that salt solutions accelerate asphalt aging through light-component depletion and heavy-component accumulation. These collective findings from prior studies establish critical theoretical foundations for designing durable pavements in saline environments.

Concrete pavements in saline soil environments of cold regions are not only subjected to vehicle loads but also severely impacted by freeze-thaw cycles (FTC) and composite salts, resulting in durability issues that shorten their designed service life. This paper induced fatigue damage in concrete based on the fatigue cycles derived from the residual strain method. It investigated the variations in the physical and mechanical properties of fatigue-damaged concrete during 100 cycles of FTC and chloride-sulfate attack, revealing the deterioration mechanisms through NMR, XRD, and SEM analysis. Utilizing the GBR algorithm, the prediction model for damage layer thickness were developed. The results showed that, due to physical crystallization, salt freeze-thaw damage, expansion of ionic attack products, and fatigue loading damage, Friedel's salt and ettringite were initially the primary products formed. Subsequently, gypsum emerged, and ultimately Friedel's salt underwent decomposition. After 10 attack cycles, the porosity and the proportion of macropores and capillary pores continued to increase, resulting in a rapid decrease in mass, dynamic elastic modulus, and flexural strength, accompanied by an increase in damage layer thickness. As fatigue damage degree increased, the pore structure degraded, thereby amplifying these changes in macroscopic properties. Incorporating basalt fibers into concrete could enhance its resistance to degradation, with the optimal dosages being 0.15 % and 0.10 %. The GBR-based model of damage layer thickness demonstrated a high degree consistency with experimental data, resulting in a correlation index of R2 = 0.989. This study lays the foundation for assessing the durability of pavement concrete in salt-freezing environments.

Roadbed engineering in alpine tundra environment is prone to frost heave and thaw settlement, cracking of pavement, uneven settlement, and other challenges under the action of seasonal freeze-thaw cycle. Wicking geotextile has important application value in frost damage control of roadbeds, but solar radiation, especially ultraviolet radiation, is one of the main factors leading to premature failure of wicking geotextile. In this study, different kinds of ultraviolet-resistant wicking fibers were developed by blending modification technology, and the various types of fibers were compared with each other in terms of their physical and mechanical properties, so as to obtain the optimal modified wicking fibers with the content of 2 % UV-1164 + 0.3 % B900 addition. Subsequently, a 20-day accelerated aging test was conducted on modified wicking geotextiles. The inhibitory effect of the modification treatment on the wicking geotextile indicating photo-oxidative aging was characterized by scanning electron microscope, and the effect on the mechanical properties maintenance of the wicking geotextile was characterized by tensile strength and top-breaking strength tests. Finally, a soil column drainage test was designed and carried out, based on which the horizontal hydraulic conductivity rate and 120-h drainage volume of wicking geotextiles before and after the modified treatment were predicted under the aging cycle of 40 d. The test and prediction dates showed that the hydraulic conductivity was deteriorated with the aging time, but the modification treatment could obviously inhibit the deterioration degree. Compared with the control group, the hydraulic conductivity of the modified wicking geotextile increased by about 0.35E-5 g/s, and the drainage capacity increased by 0.76 % at 200 h.

It is well known that the mechanical properties and appearance of adobe materials degrade significantly during freeze-thaw cycles due to the unique moisture absorption characteristics of soil particles. In order to clarify the performance degradation mechanism of adobe materials under freeze-thaw cycles, the evolution law of the pore structure, attack products, and capillary absorption characteristics were systematically studied when experiencing 10, 20, and 30 freeze-thaw cycles. The results showed that the flocculent hydration product around the Yellow River sediments and aggregate particles gradually reduced during adobe materials subjected to freezethaw cycles. Volume expansion caused by the growth of ettringite in macropores and cracks led to the deterioration in pore structure and more water participated in the subsequent freeze-thaw cycles. The porosity and pore volume of adobe materials increased with the increasing of freeze-thaw cycles, and the harmful pores of 50-200 nm rose significantly. After 20 freeze-thaw cycles, harmful pores accounted for 62.3% of the total pore volume of adobe materials, which induced an enlarged moisture transport capacity, and thus the capillary absorption coefficient increased by 18.52 g/(m2 & sdot;s1/2). As a combined result of above factors, after 30 freeze-thaw cycles, the loss rates in mass and compressive strength of adobe materials were 6.2% and 15.4%, respectively.