A clear understanding of the fatigue cracking characteristics of steel bridge deck pavement materials is crucial for ensuring pavement durability. This study investigates two typical steel bridge deck pavement materials, namely thermosetting epoxy asphalt concrete (EAC) and thermoplastic stone mastic asphalt (SMA), using the Superpave Indirect Tensile Test (IDT). An energy-based fracture model, incorporating dissipated creep strain energy and creep property indicators, was employed to evaluate the materials' fatigue resistance and analyze damage accumulation under cyclic loading. This model provides a clearer conceptual framework for analyzing asphalt concrete fatigue behavior, with the added benefit of relying on relatively few parameters. Comparative analysis revealed that EAC's fatigue resistance increased linearly with temperature, while SMA initially decreased before recovering at higher temperatures. Although the accumulated damage energy for both materials exhibited a linear temperature-dependent trend, SMA showed more pronounced accumulation. The critical temperatures for fatigue cracking were identified as 4 degrees C for EAC and 10 degrees C for SMA. Above 10 degrees C, EAC demonstrated superior fatigue resistance, while below this threshold, the relative fatigue performance of both materials depended on specific load levels and temperature conditions. These findings provide technical support for fatigue-resistant steel bridge deck pavement design and offer insights for refining fatigue testing protocols.

Epoxy asphalt is a highly effective material for steel bridge decks, with its performance strongly influenced by the material ratio. To determine the optimal material composition, mechanical properties, curing mechanisms, viscosity characteristics, and microstructure of epoxy asphalt binder (EAB) under varying curing agent contents were investigated. Low-temperature bending tests, dynamic modulus analyses, and fluorescence microscopy were conducted to determine the appropriate epoxy content. Results revealed that an increase in curing agent content enhanced the fracture elongation of EAB, indicating improved flexibility. However, the elastic modulus and tensile strength declined. The curing process of EAB was a continuous etherification reaction, significantly influencing the mechanical properties of EAB. The microscopic analysis showed a strong linear relationship between the pore radius of the asphalt phase and the tensile properties of the EAB. Meanwhile, the viscosity of EAB increased with the curing agent content. The optimal performance of EAB was observed at a curing agent content of 40 %, achieving a balance between mechanical properties and allowable construction time. For epoxy asphalt mixtures (EAM), increasing epoxy content led to higher dynamic and stiffness modulus, indicating enhanced resistance to deformation. A phase transition occurred when the epoxy content increased from 30 % to 35 %, forming a three-dimensional network structure that significantly improved resistance to low-temperature cracking of EAM. When the epoxy content exceeded 40 %, the EAM demonstrated excellent mechanical properties, making it well-suited for steel bridge deck pavements. The findings of this study provide critical references on optimizing epoxy asphalt, and advancing its application in steel bridge pavements.

Epoxy asphalt is widely used in steel bridge deck pavements, airport pavements, and high-grade roadways due to its superior performance, yet its fatigue damage evolution mechanisms remain insufficiently studied. This study investigated the fatigue performance of epoxy asphalt binder (EAB) and epoxy asphalt mixture (EAM) through linear amplitude sweep tests and four-point bending beam fatigue experiments. By analyzing fatigue parameters across varying epoxy contents and strain levels, predictive correlation models were developed between EAB and EAM fatigue performance. Furthermore, the finite element method (FEM) was employed to compare the fatigue behavior of conventional asphalt and epoxy asphalt pavements. Results demonstrate that the EAM enters a stable fatigue damage accumulation phase when the stiffness modulus decays to 75

This study investigates the fracture behavior of asphalt concrete using a combined approach of semi-circular bending (SCB) tests and digital image correlation (DIC) technology. Three types of asphalt concrete, including dense asphalt concrete (AC-13), stone mastic asphalt (SMA-13), and epoxy asphalt concrete (EA-10) were subjected to evaluation under varying loading conditions (modes I and II, mixed mode I/II) and test temperatures (-10 degrees C, 0 degrees C, and 15 degrees C). The SCB test facilitated the assessment of crucial fracture-related parameters such as load-displacement behavior, fracture toughness, and fracture energy. Simultaneously, DIC technology provided real-time insights into crack initiation and propagation by capturing detailed strain distributions and crack growth dynamics. Results indicate that the fracture behavior of asphalt concrete is significantly influenced by pre-notched cracks, loading conditions, and test temperatures. Specifically, fracture energy in pre-notched specimens was up to four times lower than that in non-notched specimens. Mode I loading resulted in lower fracture energy, a more linear crack propagation path, and a faster fracture process compared to mixed-mode I/II and mode II. EA-10 exhibited superior fracture resistance, while lower temperatures led to "brittle" fracture behavior with earlier crack initiation and failure. DIC technology provided detailed strain distribution maps, revealing critical stages of crack initiation and propagation. These findings enhance the understanding of fracture mechanics in asphalt concrete, guiding the development of more durable pavements.

The upper layer of modified SMA mixture (SMAM) and the lower layer of epoxy asphalt mixture (EAM) is a steel bridge deck pavement (SBDP) structure with application potential, but there is a lack of systematic research on it. In this study, the pavement material and structure of SMAM + EAM were optimized using mixture performance tests and finite element analysis, which provided guidance to facilitate its promotion and application. Firstly, the pavement performance and dynamic properties of SMAMs and EAMs prepared with different binders were compared to preferably select the appropriate SBDP material. Secondly, the dynamic modulus master curves of the mixtures were established to provide material parameters for pavement structure design. Finally, the FEA method was applied to comparatively analyze the dynamic mechanical response of the pavement structure for different structures, thickness combinations, and temperatures to optimize the SBDP structure purposefully. The results demonstrated that EAM had better high-temperature rutting resistance than SMAM, while SMAM had superior moisture damage and skid resistance. The modifier contents in the asphalt binder used for SMAM and EAM were recommended to be 12 wt% and 40 wt%, respectively. From the FEA results, the SMAM + EAM structure met the performance requirements of SBDP. Compared with double-layered EAM, the deformation resistance of the SMAM + EAM structure was reduced, but it was beneficial to avoid the occurrence of crack defects and interlayer shear damage. Furthermore, the recommended pavement thickness combination was 4.5 + 3.5 cm.

Shape memory materials have received great scientific attention for engineering applications because of their unique memory recoverable properties. In this study, high toughness and strong damping shape memory epoxy asphalt composites (SMEAC) were prepared, which can be widely used in the fields of bridge self-repairing expansion joints, crack sealants, vibration control, and damping devices in earthquake engineering. The mechanical properties, shape memory properties, and shape memory mechanism of SMEAC were analyzed by macroscopic and microscopic tests. The direct tensile tests showed that SMEAC has excellent toughness and strength. The temperature sweep test revealed that SMEAC has good damping properties. The shape memory recovery performance of SMEAC was analyzed by thermomechanical analyzer, and X-ray diffraction showed the change of full width at half maxima in SMEAC before and after deformation at microscopic level. Infrared spectroscopy and fluorescence microscopy indicated that the asphalt phase in SMEAC could participate in the curing reaction, which enhanced the miscibility between the asphalt phase and the epoxy resin phase. Finally, the curing mechanism of epoxy asphalt composites was derived by combining infrared spectral analysis. This work provides a theoretical reference for developing new shape memory materials and open up a new application mode for epoxy asphalt.

为解决川东北高酸性气藏目前存在的低压易漏失,低密度水泥浆强度低,H2 S与CO2混合的高酸性气体对硅酸盐水泥腐蚀大等难题,以坝南001-H1井为例进行固井技术攻关,运用紧密堆积理论提高堆积率,优选减轻剂与增强剂,设计一套高强度低密度水泥浆体系.提高固相和胶乳颗粒的含量以降低水泥石的渗透率和水泥腐蚀程度,形成防腐性能良好的水泥浆体系.采取了一系列措施,如注入高强度低密度水泥浆、注入防腐水泥浆、提高承压能力、预应力固井、控压固井工艺等,为坝南001-H1井固井作业顺利实现提供了技术支持.应用结果显示,采用该体系后,技术套管固井作业合格率达到95.95％,尾管固井质量合格率达到81.36％,效果良好.

粒子冲击钻井技术是一种在钻井液中加入钢粒子,以超过150 m/s速度经钻头喷嘴喷出冲击井底岩石实现破岩的技术,目前该技术主要通过计量输送机构转轴转速的方式,实现钢粒子体积分数调控,但存在无法直观反映粒子输送量、体积分数调控不够准确等问题.因此,文章提出了一种在线精确调控粒子体积分数的方法,设计了称重无轴螺旋输送机构和粒子提升机构,基于此研制了一种用于粒子冲击钻井系统的钢粒子精确调控装置,该装置可根据钻井液排量实时精准调控系统前端粒子体积分数.室内测试和现场试验结果表明,该装置实时精准调控的粒子体积分数误差小于1％;输送和提升机构均未出现卡堵和钢粒子堆积现象,整体运行稳定,满足粒子冲击钻井系统需求,同时有望为物料连续计量输送提供一种新的技术手段.

Based on the nonlinear damage theory, this paper aims to explore the fatigue performance of steel bridge deck asphalt pavement under multistage fatigue load. Manson–Halford cumulative damage model and the modified model were introduced to describe loading sequence effects, and interactions between multiple loads were represented in stress ratio. The fatigue life prediction method of steel bridge deck asphalt pavement was put forward, considering loading sequence effects and load interactions. The fatigue design of steel bridge deck asphalt pavement was investigated with the fatigue life prediction model. The effects of different load levels and loading sequence on the fatigue design parameters stress ratio of steel bridge deck asphalt pavement were studied. The design results were compared with experimental results, and the prediction results were based on traditional Miner’s theory. The analysis results showed that the fatigue life prediction method based on the nonlinear cumulative damage theory can effectively design and analyze the fatigue characteristics of asphalt pavement of steel bridge deck with high accuracy and reliability. The fatigue life prediction model of steel bridge deck asphalt pavement can well reflect loading sequence effects and load interactions. In addition, the design model has relatively few parameters; therefore, it can be applied to practical engineering design.

Fatigue cracks often occur in the deck asphalt pavement of steel bridges at the top of the longitudinal stiffening rib. To prevent this issue, the traditional design strategy of the steel bridge deck asphalt pavement structure was optimized, and a new approach is presented. This optimization technique exploits the strength simulation of the steel—epoxy asphalt pavement structure, and the stress concentration location is subsequently determined. A solid model of stress concentration including sensitive areas is then established. We examined the stress maximum point of the asphalt pavement layer at the top of the longitudinal stiffeners and the stress variation of the asphalt pavement layer at the top of the longitudinal stiffeners. To reduce the stress of the top pavement layer of the longitudinal stiffeners, an optimization method that combines orthogonal experimental design, neural network (BP), and genetic algorithm (GA) is presented. A design strategy for the steel—epoxy asphalt pavement structure and GA—BP optimization method was utilized to optimize the structure of the steel—epoxy asphalt pavement for Sutong Yangzi River Bridge. We confirmed that the presented approach improved fatigue reliability and established the efficacy of the design strategy and optimization method.

This paper explored whether air pollutants influenced acute aortic dissection (AAD) incidence in a moderately polluted area. A total of 494 AAD patients' data from 2013 to 2016 were analyzed. The results showed that AAD had the strongest associations with PM10, SO2, NO2, CO, and O3 on the day before an AAD incident (lag1) and with PM2.5 two days before an incident (lag2) in single-pollutant model. In the three-pollutant model, PM10 was associated with the highest risk of adverse effects (RR = 1.37, 95% CI: 1.22, 1.53), whereas PM2.5 was associated with the lowest risk (RR = .83, 95% CI: .79, .88). Both PM2.5 and PM10 were affected by season, and SO2 was significantly different between heating and non-heating seasons as well. This study revealed significant associations between short-term PM2.5, PM10, and SO2 exposure and daily AAD incidence, showing that PM10 and SO2 were strong predictors of AAD incidence in a moderately polluted area.

The surface deflection of asphalt pavement reflects the strength and stiffness of the entire structure, which can be used to evaluate the rutting life of asphalt pavements. However, it is influenced by various stochastic variables including traffic loads, material properties and structural thickness of each pavement course. The uncertainty of above stochastic variables is of significance for accurately predicting the rutting life of asphalt pavement. In this study, the statistical characteristics of stochastic variables of asphalt pavement were assessed based on the field data collected from asphalt pavement projects. A unique formula with a fairly good accuracy was found using multiple linear regression based on numerical simulation results to ease the calculation of pavement deflection during the reliability analysis. It is shown that the stochastic variables of asphalt pavement can be well characterized by normal distribution or logarithmic normal distribution. The regressed formula to calculate the surface deflection of pavement has a fairly good accuracy with an error of less than 6.0% compared to the numerical method. The proposed surface deflection-based reliability analysis can be used easily to evaluate the influence of input parameters on the rutting life and to guide the structure design of asphalt pavement with required reliability.

Epoxy asphalt (EA) concrete is widely used in constructing long-span steel bridge pavements (SBDPs). This study aims to derive a fatigue damage evolution law, conducting an experimental investigation of SBDP. First, a general theoretical form of the fatigue damage evolution law of materials is established based on the thermal motion of atoms. Then, fatigue experiments demonstrate that this evolution law well represents the known damage–life relationships of SBDP. Taking into account the experimental relationships between damage and fatigue life under symmetrical cyclic loadings with different overload amplitudes and temperature variations, a detailed damage evolution law is deduced. Finally, the role of damage accumulation is discussed on the basis of the proposed damage evolution law for the extreme situation of heavy overload and severe environments. The results show that both heavy loading and falling temperatures increase the fatigue damage of SBDP considerably; therefore, SBDP should avoid heavy loading combined with winter temperatures. EA shows a fatigue life two to three times longer than that of modified matrix asphalt (SMA) or guss asphalt (GA). For the same thickness, EA pavement is demonstrated to be more suitable for an anti-fatigue design of large-span SBDP under high traffic flows and low temperatures.

Epoxy asphalt (EA) concrete is widely used in constructing long-span steel bridge pavements (SBDPs). This study aims to derive a fatigue damage evolution law, conducting an experimental investigation of SBDP. First, a general theoretical form of the fatigue damage evolution law of materials is established based on the thermal motion of atoms. Then, fatigue experiments demonstrate that this evolution law well represents the known damage-life relationships of SBDP. Taking into account the experimental relationships between damage and fatigue life under symmetrical cyclic loadings with different overload amplitudes and temperature variations, a detailed damage evolution law is deduced. Finally, the role of damage accumulation is discussed on the basis of the proposed damage evolution law for the extreme situation of heavy overload and severe environments. The results show that both heavy loading and falling temperatures increase the fatigue damage of SBDP considerably. EA shows a fatigue life two to three times longer than that of modified matrix asphalt (SMA) or guss asphalt (GA). For the same thickness, EA pavement is demonstrated to be more suitable for an anti-fatigue design of large-span SBDP under high traffic flows and low temperatures.

针对自主研发的橡胶树脂(PR)改性沥青进行了老化性能研究.采用薄膜老化烘箱和自主设计研发的紫外老化烘箱模拟沥青的热氧老化和光氧老化过程,对老化前后的PR改性沥青进行了常规性能试验、流变试验和凝胶色谱的试验对比.结果表明:PR改性技术能够很好地提高沥青的抗老化性能;PR改性沥青老化后针入度、软化点性能改变不大且RTFOT老化后高温等级较高,另外PR改性沥青的分子量分布曲线变化较小,其耐老化性能得到明显改善;可以采用沥青的重均分子量和分散度进行宏观性能的部分表征,沥青重均分子量和分散度越大,沥青温度敏感性越小,耐老化性能越好.

INTRODUCTION Basic research is the bedrock of science and technology（S＆T）progress and industrial transformation,and the cornerstone to making China a world leader in S＆T.In the new round of the technological and industrial revolution,basic research is assuming an increasingly prominent role.Aiming at becoming a world leader in S＆T by 2050,China should

共享经济正改变着人们的生活方式,城市公共交通系统应该顺应共享经济的潮流进行转型,构建新的公交服务模式,该模式以乘客体验为核心,以提升出行服务质量为目标.文章在指出目前公共交通系统发展存在问题的基础上,分析新的交通技术、交通工具与共享出行理念对交通行业的影响,进而介绍"出行即服务"这一全新的交通理念,在该理念指导下各公共交通系统在未来将打破系统界限,强化合作和服务资源共享,形成多模式、多层级的公交体系.

It is well known that temperature along the depth of concrete pavement slabs is highly nonlinearly distributed. Utilising appropriate methods is crucial for quantifying an equivalent temperature gradient and the associated curling and stress calculations. The existing methods to obtain a temperature gradient are either simply by subtracting the bottom surface temperature from the top surface temperature (Delta Ttop-bottom) or by converting the nonlinear temperature distribution to an equivalent temperature difference (Delta T-eq) based on the measured temperature distribution. None of the above methods are based on the strain which is the direct cause of slab curling. This study measures the strain development at different depths of field-instrumented concrete pavement slabs. A new strain-based quantification method for an equivalent temperature gradient (Delta T-strain) is developed based on the field strain measurements. The quantified Delta T-strain is then compared to Delta Ttop-bottom and Delta T-eq. Their validity is verified by the field-measured slab-curling data. The newly developed strain-based method provides an alternative way for the temperature-associated performance evaluation of the concrete pavement slab.

With the exploration and development of tight oil and gas,mirco pores (pore diameter ＜30 μm) in reservoir play an increasingly important role in the occurrence and migration of oil and gas.Taking tight sandstone in the ultra-deep (＞6 000 m) Cretaceous Bashijiqike Formation in Kuqa foreland thrust belt as an example,laser confocal microscopy,scanning electron microscopy,electron probe,high pressure mercury injection and other sequence parallel characterization experiments were conducted on the casting thin sections by selecting representative experimental samples,so as to analyze the types,characteristics and genesis of reservoir micro pore and its effect on reservoir property.The results show that nanoscale mirco pores are dominantly found in tight sandstone reservoirs of the ultra-deep Cretaceous Bashijiqike Formation in Kuqa foreland thrust belt,including intergranular micro pore,intragranular micro pore and intercrystalline micro pore.Intergranular mirco pores at the micro-nanoscale level are dominant,while intragranular and intercrystalline mirco pores are nanoscale ones.Mirco pores are formed mainly as a result of secondary origin with supplement of primary origin,and corrosion transformation is a key factor for secondary origin.Reservoir microporosity in the study area is about 2.8％,and the contribution rate of mirco pores to reservoir porosity decreases with increasing porosity.Reservoir throat connecting mirco pores is at the nanoscale,with the pore throat radius of 2-400 nm and peak value of 5-50 nm.The pore throat radius with the main contribution to permeability is 20-400 nm.Methane molecules form a viscous flow in mirco pores,making great contribution to gas productivity.Various types of mirco pores are different in scale dimensions,geometrical morphology,intercommunication and gas occurrence and migration characteristics.

中国产学研合作创新大会在中国产学研合作促进会的有力推动下,已经成为我国产学研合作领域一年一度的盛事,成为聚集各方力量、推动科技与经济社会发展深度融合的有效载体.我借此机会就产学研合作工作谈三点意见.