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Review of design for combined base asphalt pavements with asphalt treated base and cement stabilized subbase
LI Xuelian, CHEN Peng, and CHA Xudong

Date posted: 11-24-2023
DOI: https://doi.org/10.14048/j.issn.1671-2579.2023.05.001

At present, there are great differences in the material composition, structure form, damage type, disease cause, design index, and design method of asphalt pavement with asphalt-treated base and cement-stabilized base in various countries. In view of this, this paper summarized the material type and structure form selected in China and abroad and analyzed the damage type and disease cause of this kind of asphalt pavement structure. This paper discussed the differences in the design methods of combined base asphalt pavement in different countries and summarized the disease control types and design indexes in different countries. On this basis, the reasonable material, structure combination, and design indexes of combined base asphalt pavements were recommended, which provided a reference for the design and application of this kind of asphalt pavement.

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A Review of Pavement Condition Evaluation Index Systems in China and Abroad
CHEN Leilei, YANG-LI Wenyun, LI Wei, Muhammad Thlha, and QIAN Zhendong

Date posted: 10-27-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.05.007

With the increasingly complex operating conditions of roads, it has become a consensus among countries to improve the accuracy and systematicness of maintenance decisions. Since the pavement condition evaluation index system is the core tool supporting the judgment of schemes, its construction method and applicable ability directly affect the maintenance efficiency and resource allocation level. Based on the construction logic of the index model, the scoring mechanism of grade division, and the conditions of road grade adaptation, the characteristics of the evaluation index systems in typical countries in China and abroad were compared and sorted out. The internal causes affecting the characteristics of the index system were discussed from in-depth perspectives such as management concepts and institutional arrangements. Research findings show that some systems abroad emphasize hierarchical structural response or public experience, while in China, unified deployment and hierarchical downward management are emphasized. In China's case, the system has a certain foundation in terms of universality and standardization, but there are obvious shortcomings in threshold adjustment, scene adaptation, and system integration. Therefore, suggestions are proposed including setting dynamic thresholds in combination with maintenance goals, enhancing the adaptability to various types of road operating environments, and promoting the effective integration of evaluation results with the actual management process, which provides ideological support for the structural optimization and institutional coordination of the evaluation system.

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Review of Snow and Ice Melting Techniques for Road and Bridge in Cold Regions
TANG Liyun, SHAO Haitao, TANG Huaming, QIU Peiyong, DU Xiaoqi, ZHANG Lei, and PENG Hui

Date posted: 10-28-2024
DOI: https://doi.org/10.14048/j.issn.1671-2579.2024.05.003

Snow and ice melting of road and bridge surfaces is crucial for traffic safety，but current research on snow and ice melting techniques mainly focuses on engineering effects and technical evaluation，without the analysis and elaboration from the perspective of their mechanisms.To this end，based on the different mechanisms，this study divided snow and ice melting techniques into three types and summarized them：passive deicing，active deicing，and energy utilization deicing.This study systematically evaluated the advantages and disadvantages of traditional deicing methods such as deicing agents and mechanical deicing，analyzed two active deicing techniques，namely inhibitive freezing pavement and phase change material pavement，discussed the environmental-friendly method for road deicing by using phase change materials，and introduced the mechanisms of different energy utilization deicing techniques.This study analyzed the existing road deicing techniques，their actual application effects，and existing problems，to provide foundational support for the research of snow and ice melting on roads and bridges in cold regions.

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An Overview on the "ReusePotential" for Managing Shield Tunnel Spoilsas Resource
ZHANG Junhui, LI Hai, YANG Hao, WANG Hualei, and HAN Shanpeng

Date posted: 1-18-2024
DOI: https://doi.org/10.14048/j.issn.1671-2579.2022.06.001

In response to the challenges posed by massive shield muck production and inadequate disposal solutions, scholars have systematically reviewed the research on shield muck recycling technologies. Based on the challenges faced by the treatment of shield muck in China, this paper formed a systematic understanding of the classification of shield muck, the progress of resource recycling technologies, and typical applications, introduced the pretreatment methods of shield musk in China and abroad, and summarized the application scenarios and resource recycling technologies of shield musk in detail. Then, the paper analyzed the problems of shield musk recycling technologies, such as expensive curing agents, serious pollution, lack of pollutant analysis of roadbed backfill materials, low strength of recycled brick, and unconspicuous market benefit. The standardized technical process of “pre-classification treatment of shield musk, feasibility evaluation of recycling, resource recycling scenario, and performance and benefit evaluation” for shield musk recycling was constructed. The research directions of the development of shield musk curing agents and the migration of pollutants were emphasized. Finally, the development trend of shield musk recycling technologies was prospected.

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Research on Enhancement of Toughness Performance in Polyurethane-Modified Epoxy Asphalt
LIANG Bo, LIAO Xintao, LIAO Wei, JIANG Hui, and QIN Ruiming

Date posted: 10-27-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.05.011

To solve low toughness and high brittleness of epoxy asphalt under low-temperature conditions, in this study, polyether-type polyurethane (JMPU) and polyester-type polyurethane (JZPU) were employed to prepare modified epoxy asphalt. Firstly, the Brookfield viscosity test, infrared spectroscopy test, and fluorescence microscopy were utilized to characterize the curing process. The curing time and curing temperature of JMPU and JZPU modified epoxy asphalt were 3 h/140°C and 4 h/150°C, respectively. With styrene-butadiene-styrene block copolymer (SBS), a common modifier, as the control, the performance changes of epoxy asphalt before and after modification with different toughening agents were evaluated through mechanical tensile test, rheological property test, multiple stress creep recovery (MSCR) test, and storage stability test. The research findings indicate that the polyurethane system can effectively enhance the elongation at break, low-temperature performance, and storage stability of epoxy asphalt by forming an interpenetrating network structure (IPNs) with epoxy asphalt, while maintaining excellent high-temperature performance. The elongation at break of JMPU-modified epoxy asphalt and its low-temperature creep stiffness at ‒12°C can reach 233% and 169 MPa, respectively. Results of an aging test on the toughened and modified epoxy asphalt show that the incorporation of JMPU and JZPU effectively mitigates the adverse effects of aging on epoxy asphalt performance, evidenced by lower creep stiffness aging index and rutting factor aging index, as well as higher creep rate aging index. Therefore, the addition of the PU system as a toughening agent improves the toughness of epoxy asphalt and enhances its compatibility and anti-aging performance.

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Design Featuresand Cast-in-Place Construction Technique of Support Methods of Continuous Box Girder for Mountain Road
LI Youming, BAI Xiohong, and WANG Qifu

Date posted: 1-18-2024
DOI: https://doi.org/10.14048/j.issn.1671-2579.2022.06.027

According to the engineering environment and functional requirements of highway bridges in mountainous areas, the design characteristics of continuous box girder bridges with variable widths and the technical difficulties of cast-in-place construction by support method were analyzed. Based on the engineering environment and structural design characteristics, the technical feasibility, safety, operability, and economy of various support systems such as full-hall support, beam-to-column support, and combined support, hoop (steel bar) or bullleg support with pier, and floor mold were analyzed. The composite full-hall support and beam-to-column support scheme was scientifically and reasonably selected, and its construction quality control points were introduced. In view of the economic difference between the steel formwork and the wood formwork system, the wood formwork system was recommended, and the influence of internal mold removal on the bridge structure was analyzed. Based on the advantages and disadvantages of the first and second pouring schemes of box girder concrete, the technical countermeasures for the construction quality control of reinforcement, concrete, and prestress of continuous box girder bridges with variable width on mountainous highways were described in detail.

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Influence of Reflective Cracks on the Mesoscopic Mechanical Behavior of Asphalt Pavement Structures
MA Hui, REN Zhongshan, and WANG Min

Date posted: 10-27-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.05.009

To gain an in-depth understanding of the mechanical behavior of existing asphalt pavement structures affected by reflective cracks, a macro-meso coupled model of a typical semi-rigid base asphalt pavement was established based on a continuum-discrete coupling method. By incorporating reflective cracks with varying vertical lengths, the stress transfer paths, mesoscopic particle stress states, and displacement evolution of the pavement structure were analyzed. The results indicate that the coarse aggregate skeleton and the surrounding mortar collectively bear more than 75% of the traffic load, forming a critical load transfer system, and that a significant linear correlation exists between the vertical stress and effective stress of particles along the primary stress transfer path. The vertical propagation of reflective cracks significantly disrupts the original stress diffusion path, leading to force chain concentration, increased contact forces, and a substantial rise in effective stress. When the crack extends to the pavement surface, the displacement field of particles near the crack changes significantly, with enlarged displacement magnitudes, resulting in a pronounced degradation of fatigue performance across all structural layers.

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Mechanical and Durability Properties of Flowable Solidified Soil Based on Waste Slurry from Pile Foundations
LI Hongzhen, WU Shuxin, CHE N Chen, YIN Shurui, WANG Luwen, ZHU Kongyou, and FENG Zhuangzhuang

Date posted: 10-27-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.05.004

To address the challenge of pile foundation waste slurry disposal, this study proposes a resource utilization approach based on alkali activation technology, enabling rapid solidification of the waste slurry into a flowable solidified soil suitable for engineering backfill. An orthogonal experimental design was employed to determine the optimal mix ratio of the solidifying agent, identified as cement:slag:fly ash = 0.5:0.35:0.15, with NaOH accounting for 6% of the total mass. Based on this, the mechanical and durability properties of the solidified soil were systematically investigated. Results indicate that within a certain range, both unconfined compressive strength and splitting tensile strength increase linearly with higher solidifying agent content and longer curing age, and a fitting relationship between the two was established. An increase in construction delay time weakens the mechanical performance, highlighting the need for appropriate time control during construction. In terms of durability, resistance to wet-dry cycles improves with greater solidifying agent content, though a saturation effect is observed. The water stability coefficient shows different growth trends with changes in solidifying agent content and immersion age. Freeze-thaw cycles significantly degrade the strength, and increasing the solidifying agent content does not effectively improve frost resistance. The findings provide theoretical and technical support for the engineering application of premixed flowable solidified soil.

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Design and Performance of Solvent-Based Regenerated Cold Feed for Fine Screening
YAN Chunpeng, ZHU Yaoting, FAN Xiangyang, LIU Bin, and YI Zhao

Date posted: 10-27-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.05.024

To overcome the limitations of evaluatio n methods for the performance of cold patching asphalt mixtures, this paper systematically studied the pavement performance and its evaluation system of solvent-based cold patching asphalt mixtures using fully finely stripped and sieved reclaimed materials. Meanwhile, a multi-stage research approach was adopted to conduct an in-depth investigation. Firstly, the material ratio of the new solvent-based cold patching liquid was optimized based on the orthogonal test design method. Subsequently, an evaluation system covering key performance indicators and the corresponding technical standards was constructed. On this basis, the developed evaluation method was applied to conduct a comprehensive performance characterization of the new recycled cold patching asphalt mixture, with the influence laws of fiber and diluent content on the performance of cold patching materials analyzed. The results show that the optimally designed recycled cold patching mixture with fully finely stripped and sieved reclaimed materials has obvious technical advantages, which are specifically reflected in the high initial and formed strength, good cohesion, excellent construction workability, and strong water stability. The proposed performance evaluation system can effectively characterize the actual service performance of materials. When the mixture indicators meet the recommended standards, the quality of pavement pothole repair can be significantly improved, and the service life of the repaired structure can be extended.

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Preparation and Road Performance of Cold Patching Materials Modified by Polyurethane Prepolymer
YANG Wei, ZHAI Xueguo, GUO Weixiong, and CHI Haozhan

Date posted: 10-27-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.05.025

Traditional cold asphalt mixtures present challenges such as inapplicability in humid environments and poor durability when used for repairing potholes in asphalt pavements. To address these issues, with polyurethane prepolymer (PUA), 70# base asphalt, and additives as raw materials, a cold patch asphalt base liquid with optimal comprehensive performance was developed using the simplex design and the ideal point method. Cold patching asphalt mixtures were also prepared, with pavement performance systematically evaluated. It indicates that the PUA content has the greatest influence on the low-temperature performance and tensile strength of the cold patching asphalt liquid. The effects of components on workability and volatility follow the order: diluent > asphalt > PUA. The prepared liquid also exhibits excellent storage stability and adhesion. Furthermore, the PUA-modified cold patch materials demonstrate good strength, high-temperature stability, low-temperature crack resistance, moisture resistance, and fatigue resistance. These findings facilitate the application of polyurethane prepolymer-modified cold patch asphalt in rapid repair projects for asphalt pavement distress.