Investigation of the environmental impacts of steel deck pavement based on life cycle assessment

To investigate the environmental impacts of steel deck pavement through the whole life cycle,the steel deck pavement was divided into five stages:raw materials production,asphalt mixture mixing,pavement construction,operation management,and pavement removing stage.Based on the process-based life cycle assessment(PLCA)method,the calculation methods of energy consumption and gas emissions of two typical steel deck pavement systems(EA+EA pavement and GA+SMA pavement)were determined.The data lists of two pavements were analyzed,and the calculation model was built.Four characteristic indices including primary energy demand(PED),global warming potential(GWP),acidification potential(AP)and respiratory inorganics(RI)were used to quantify the environmental impacts of two pavements.The results show that the environmental impact of the GA+SMA pavement is more than 1.3 times that of the EA+EA pavement.Moreover,the critical stage of energy-saving and emission-reduction of EA+EA pavement and GA+SMA pavement are the raw material production stage and asphalt mixture mixing stage,respectively.

Influence of longitudinal slope on the mechanical response of steel deck pavement

In order to study the influence of longitudinal slope on the mechanical response of steel deck pavement,a method of slope-modulus transformation was proposed for the mechanical analysis of the steel deck pavement based on the time-temperature equivalence principle.Considering the mechanical action on a slope,a finite element model of the deck pavement was established to determine the critical load position of tensileand shear stress of the steel deck pavement.Additionally,the influence of longitudinal slope on the mechanical response of the deck pavement under the conditions of uniform speed and emergency braking was analyzed.The results indicate that the maximum transverse tensile stress at the pavement surface and the maximum transverse shear stress at the pavement bottom are always greater than their longitudinal counterparts under uniform speed.Under emergency braking,however,the critical slope gradient of t e maximum transverse and longitudinal tensile stress at t e pavement surface is 6%.The maximum longitudinal shear stess at t e pavement bottom is always greater ta n t e maximum tansverse shear stess.This stidy is helpful in t e strctural design of large longitudinal slope steel deck pavements.

Research on the Evaluation System of Epoxy Asphalt Steel Deck Pavement Distress Condition

Epoxy asphalt concrete has been one of the mainstream technology of steel deck pavement in China. But little specification about evaluation system for its distress condition has been researched and maintenance was still unsystematic. The section weight coefficient of different distress is proposed by analyzing the applicability of the “Highway Performance Assessment Standards”. Indexes mainly including SDPCI PDR and PCR are presented to evaluate its distress condition. The evaluation system and maintenance plan decision tree were recommended which can assist scientific maintenance of epoxy asphalt steel deck pavement.

Developments of Gussasphalt System on Steel Deck Pavement

With the development of steel deck paving technology, the associated gussasphalt pavement system also develops maturely. In this paper, the structure characteristics and performance advantages are thoroughly explained by introducing the development course of gussasphalt. The material composition, properties and application effect of three typical pavement methods are analyzed. This paper is intended to give a relatively clear understanding regarding the specific features of gussasphalt, and provide some guidance to further expansion concerning gussasphalt pavement.

Design and evaluation of UHPP steel bridge deck pavement for high-temperature and rainy regions

To enhance the serviceability of steel bridge deck pavement(SBDP)in high-temperature and rainy regions,a concept of rigid bottom and flexible top was summarized using engineering practices,which led to the proposal of a three-layer ultra-high-performance pavement(UHPP).The high-temperature rutting resistance and wet-weather skid resistance of UHPP were evaluated through composite structure tests.The internal temperature distribution within the pavement under typical high-temperature conditions was analyzed using a temperature field model.Additionally,a temperature-stress coupling model was employed to investigate the key load positions and stress response characteristics of the UHPP.The results indicate that compared with the traditional guss asphalt+stone mastic asphalt structure,the dynamic stability of the UHPP composite structure can be improved by up to 20.4%.Even under cyclic loading,UHPP still exhibits superior surface skid resistance compared to two traditional SBDPs.The thickness composition of UHPP significantly impacts its rutting resistance and skid resistance.UHPP exhibits relatively low tensile stress but higher shear stress levels,with the highest shear stress occurring between the UHPP and the steel plate.This suggests that the potential risk of damage for UHPP primarily lies within the interlayer of the pavement.Based on engineering examples,introducing interlayer gravel and optimizing the amount of bonding layer are advised to ensure that UHPP possesses sufficient interlayer shear resistance.

Dynamic analysis of pavement on long span steel bridge decks

In order to analyze the dynamic response of pavement on long-span steel bridge decks under random dynamic loads, the irregularities of the pavement surface is simulated with the power spectrum density function, and the random load is calculated according to a vehicle vibration equation of vehicle model. The mechanical responses of three different cases are compared by using a transient dynamic analysis method, i. e., under random dynamic load, constant moving load and dead load respectively. The results indicate that the mid-span of two adjacent transversal diaphragms is the worst load position. The maximum vertical displacement and the maximum transversal tensile stress of the pavement are 1.33 times and 1.39 times as much as those when only considering the impact coefficients. This study not only provides a theoretical basis for the mixture design and structural design of pavement, but also puts forward higher demand on the construction and maintenance for steel deck pavement.

A systematic review of steel bridge deck pavement in China

As an important part of steel bridge deck,the engineering quality and service condition of steel bridge deck pavement(SBDP)directly affects the capacity and operational efficiency of the bridge.This paper reviews the history of the development of SBDP in China over the past 20 years from the exploration stage,rapid development stage and prosperity stage.The development and application of SBDP at different stages are discussed in terms of materials,structure,design,performance evaluation,maintenance and rehabilitation,respectively.The advantages and disadvantages of different pavement materials and structures,and the application of different research methods are summarized.The review shows that the improvement of pavement materials and structures and the development of new materials should be further studied on the multi-scale to enhance the durability of pavement materials,so as to extend the service life of pavements.The design method of SBDP related to the synergistic effect of vehicle,pavement and bridge should be established,and the design concept and method standard of rigid base pavement structure should be improved and formulate a complete design standard.In addition,multi-disease intelligent identification system and equipment should be studied to track the entire course of disease development in real time.And it is necessary to develop appropriate algorithms to select and classify the complex data of disease and maintenance history.

Design and laboratory evaluation of fog-sealed chip seal on epoxy asphalt pavement for steel bridge deck

In order to improve the surface performace of epoxy asphalt pavement （EAP） for steel bridge deck, an epoxy asphalt chip seal （ ECS） covered by a cationic emulsified asphalt fog seal （i. e., fog-sealed chip seal） isproposed and a laboratory study is conducted to design and evaluate te fog-sealed chip seal. First, the evaluation indices and methods of te chip seal on steel bridge deck pavement were proposed. Secondly, the worst pavement conditions during te maintenance time were simulated by te small traffic load simulation system MMLS3 and the short-term aging test for minimizing the failure probability of chip seal. Finally, the design parameters of fog-sealed chip seal were determined by the experimental analysis and the performance of the designed fog-sealed chip seal was evaluated in thelaboratory. Results indicate that the proposed simulation method of pavement conditions is effective and the maximal load repetitions on the EAPslab specimen are approximately 925 300 times. Moreover, the designed fog-sealedchip sealcan provide a dense surface with sufficient skid resistance,aggregate-asphalt aahesive performance and interlayer shearing resistance.

Fatigue damage analysis of epoxy asphalt pavement for steel bridges considering coupled effects of heavy load and temperature variations

To investigate the fatigue damage of epoxy asphalt pavement(EAP)under a heavy load and a d temperature load,the load-figure of the heavy load on the steel bridge deck pavement(SBDP)was simulated first,and the temperature distribution of SBDP during the temperature-fall period in winter was also calculated.Secondly,t e moving heavy load coupled W t the most unfavorable temperatre load was applied to the SBDP,and the tensile stress on the top of SBDP was calculated.Finally,the fatigue damage of EAP was evaluated considering the extreme situation of heavily overloaded and severe environments.The results show that botte heavy load and the temperature load during t e temperature-fall period c n increase the tensile stress on the top of SBDP significantly.In the exteme situation of heavily overloaded and severe environments,a fatigue crack is easily generated,and thus the SBDP should avoid t e coupling effects of the heavy loadand the temperature load in winter.

典型钢桥面铺装体系生命周期碳足迹分析

为了量化钢桥面铺装体系的碳排放量,应用基于过程的生命周期评价方法分析了钢桥面铺装体系的生命周期碳足迹.从材料生产、施工建造、运营管理、维修养护、废弃处置和运输6个过程构建了钢桥面铺装体系碳排放的生命周期清单数据库,采用国际平整度指数建立铺装层行驶质量衰减下的碳排放预估模型,利用SMUO仿真软件进行交通延误仿真获取相关参数以建立交通延误的碳排放模型,建立了相应的碳足迹量化框架和模型,同时对下层EA(环氧)+上层SMA(沥青玛蹄脂)典型铺装体系进行了实例分析.结果表明,维修养护和运营管理阶段贡献了碳排放总量的近80%,交通延误导致的额外碳排放约达到了碳排放总量的24%,固化剂、喷砂除锈等材料或施工工艺也分别贡献了碳排放总量的8.11%和5.42%.

热拌环氧浇注式沥青混合料性能试验研究

浇注式沥青混合料密水性、协调变形能力及耐久性优,而环氧沥青混合料的强度及高温抗重载能力极为突出,为实现两种混合料的优势集成,研发了环氧浇注式沥青混合料。对3种来源的热拌环氧沥青进行环氧树脂、热拌环氧沥青力学性能及170℃黏度试验;在热拌环氧浇注式沥青混合料配合比设计基础上,开展搅拌时长为45,135 min的混合料流动性、马歇尔、贯入度、车辙、弯曲及疲劳性能试验。结果表明,3种环氧树脂和热拌环氧沥青的力学性能基本一致,170℃黏度达1 Pa·s时间在3 h以上;混合料性能随搅拌时长增加衰减较大;环氧沥青类型对除流值和极限弯拉应变外性能指标影响不显著。搅拌45 min的XB环氧浇注式沥青混合料性能最优,流动度<5 s且可施工流动性维持时间在135 min以上,马歇尔稳定度超过48 kN,动稳定度达到18945次/mm,贯入度增量仅0.1 mm,-10℃极限弯拉应变>3000με,疲劳性能指标冲击韧性达到3517 N·mm,各项性能远超常规浇注式沥青混合料,多项指标也超过环氧沥青混合料,同时成本也较低。热拌环氧浇注式沥青混合料较好兼顾了浇注式沥青混合料和热拌环氧沥青的优点,可有效提高浇注式沥青混合料高温强度,对提高我国钢桥面铺装质量及耐久性具有重要意义。

Mechanical properties of epoxy asphalt mixture pavement with lightweight aggregate applied on bascule bridge

The high temperature anti-rutting performance,water stability and low temperature bending property of epoxy asphalt mixture with 0%,15%,25%,40%,and 70% granulated and circular lightweight aggregates by weight are tested,respectively.The dynamic responses under the vehicle load and in the opening process are analyzed to obtain the mechanical responses of pavements by using the finite element method.The complicated structure including a steel deck and a waterproof adhesive layer is made to verify the bond strength of the 2451-type epoxy asphalt binder.Research results show that the epoxy asphalt mixtures with lightweight aggregate replacement percentages from 0% to 70% all satisfy the requirements for steel bridge pavements.The epoxy asphalt mixture with a 70% circular lightweight aggregate replacement percentage is recommended because of its smaller density when compared with other epoxy asphalt mixtures.The shear stress increases with the increase in the opening angle and achieves its maximum at the maximum opening angle of 85°.Test results show that the Tianjin Bascule Bridge can be used for first opening after a 3 d pavement conditioning.

钢箱梁桥面防水粘结层最佳材料配比设计与性能评价研究

为了研究防水粘结层中粘结层、防水层和防腐层中材料用量对其防水粘结体系性能的影响,对钢桥面粘结层、防水层和防腐层最佳材料用量进行了研究。研究发现丙烯酸防腐底涂层用量约150g/m^(2)时涂刷后的强度增强较为明显;当甲基丙烯酸树脂防水层单层湿膜厚度为1.2mm时材料用量最接近中值且成品外观均匀性较好;丙烯酸树脂粘结剂用量在175g/m^(2)时较为合适且能够全部覆盖且无堆积,经过研究得到了较为满意的施工标准用量,可为类似工程提供一定的参考。

基于黏度的环氧沥青ESMA施工温度研究

环氧沥青在施工过程中,黏度是不断变化的,凝胶体系在内部起到控制作用。为保障环氧沥青ESMA的性能,通过精准控制其黏度来获得最佳施工工艺。采用布氏旋转黏度计,测试环氧沥青在不同温度条件下的黏度,并总结其随时间变化的特性,得出环氧沥青混合料在不同容留温度、不同容留时间、不同压实功下的成型碾压效果,为环氧沥青混合料施工温度控制及摊铺碾压关键时机的选择提供参考。

猎德大桥钢桥面铺装维修方案研究与工程实施

首先,分析了猎德大桥钢桥面铺装的病害特点。结合猎德大桥钢桥面铺装层的现状,在考虑施工时间和交通通行的情况下,开展了猎德大桥钢桥面铺装维修方案的研究。确定了保留RA05层,翻新SMA10的维修方案,同时,对猎德大桥铺装层材料进行比选,确定选用PG-100高黏改性沥青SMA10作为铺装上层,选用PG-82改性沥青作为粘结层。其次,介绍了PG-100高黏改性沥青SMA10铺装维修方案的内容和施工要点。最后,对新铺的桥面状况持续观察一年,检测结果都达到了预期目标。猎德大桥钢桥面铺装维修方案为类似工程提供了参考。

钢桥面铺装体系用环氧重防腐涂料制备与研究

近年来部分工程案例显示环氧富锌涂层在钢桥面防护效果不理想,尤其是在南方沿海的大跨径钢桥面防护中会过早发生腐蚀破坏,主要原因是富锌涂料中的锌粉在高湿热、高温环境下与水气反应而失效,另一方面富锌涂料颜料体积浓度(PVC)高,脆性大,渗透能力弱,在车载压力下容易与基材、中间层滑移等。本文采用韧性环氧树脂、增韧剂、柔性固化剂制备了一种高韧性非锌环氧重防腐涂料,通过拉伸试验、耐热盐水浸泡试验、盐雾试验、高温附着力等方法研究了其力学性能和防腐性能。结果表明,采用聚氨酯增韧改性环氧树脂SLpu、低相对分子质量聚氨酯改性环氧树脂增韧剂Dslu以及复配固化剂[m(聚醚胺固化剂T)∶m(柔性固化剂F)=5∶1]制备的高韧性非锌环氧重防腐涂料拉伸性能、耐盐雾性能和耐热盐水性能优异,尤其是耐热盐水性能远超于环氧富锌涂料,更适合南方沿海高湿环境大跨径钢桥面铺装体系的防护,对解决目前钢桥面防护体系使用寿命不足的问题有一定的参考意义。

钢桥面SMA+UHPC铺装层应力有限元分析

文中依托于某钢桥,基于正交异性板+铺装层复合模型进行最不利荷载位置分析,通过分析铺装层横向应力、纵向应力、层间剪切力确定荷载作用横向和纵向最不利位置,比较双层沥青玛蹄脂碎石混合料(SMA)铺装结构和沥青玛蹄脂碎石混合料+超高性能混凝土(UHPC)铺装结构沿横向、纵向、竖向的应力分布,分析UHPC层厚度对铺装层应力的影响。结果表明,铺装层最不利荷载作用位置为荷载中心位于U肋和顶板交界处上方和横隔板跨中;SMA+UHPC铺装层结构能显著减小SMA层的最大拉应力,延缓SMA层开裂;UHPC层厚度增加对减小SMA层最大横向应力效果明显,而对最大纵向拉应力影响较弱。

环氧沥青钢桥面铺装施工技术分析

该文以清云高速公路肇云大桥的钢桥面铺装工程为例,探究环氧沥青混凝土的铺装工艺及技术要点。正式铺装前需要做好钢桥面的喷砂除锈和清洁处理,营造良好的铺装环境。然后,洒布黏结层和喷涂环氧富锌防锈漆。拌和环氧沥青混凝土,由运输车将混合料从拌和站运送到施工现场完成摊铺后,分别进行初压、复压、终压,保证摊铺料的密实度达标。最后,根据天气情况确定养护时间,养护完毕后开放通车。

轻型组合桥面体系的经济型层间黏结方案与应用研究

为解决表面铺装层早期破坏和正交异性钢桥面板疲劳开裂的技术难题,近年出现了钢-混轻型组合桥面体系的方案,将高性能混凝土通过抗剪钉与钢箱梁结为整体,表面层采用35 mm~50 mm沥青混合料,其中刚柔界面黏结性能是该方案实施成败的关键。依托珠海市金海公路大桥钢桥面铺装工程,针对“FRC+SMA10”轻型组合桥面体系的铺装层层间黏结性能展开研究,先通过Midas构建桥面铺装数值模型,分析了重载交通下层间最大应力分布情况,后通过试验分析了沥青层混合料设计、封层碎石撒布量因素对铺装层层间黏结性能的影响,最后推荐了最优施工方案。试验结果表明:1)沥青层混合料级配对层间黏结强度影响显著,采用细型混合料级配有助于提高铺装结构层间黏结强度;沥青用量和碎石撒布量存在最佳用量,当沥青用量为1.8 kg/m^(2)、最佳碎石撒布量为8 kg/m^(2)时,轻型组合桥面体系的层间黏结性能最优;2)采用优化后的同步碎石黏层方案,能满足有限元模型计算的最大剪应力要求,依托实体工程跟踪观测,应用效果良好,该方案具有较好的经济效益,可推广应用于同类工程。

南沙大桥钢桥面铺装防腐层施工工艺

为指导钢桥面防腐层施工,通过钢桥面板喷砂除锈及环氧富锌漆施工工艺研究,确定了喷砂除锈和环氧富锌漆施工关键技术控制指标,研究表明,抛丸机采用丸砂比为2∶1时,行走速度不得>3.0 m/min;采用喷枪喷涂环氧富锌漆,漆膜厚度均匀性要优于人工滚涂,且合格率相对较高;喷枪喷涂和人工滚涂环氧富锌漆对其拉拔强度影响不大。通过防腐层施工工艺研究,验证了防腐层施工关键技术与工艺的合理性。