Investigation of cost-effectiveness of highway asphalt pavement maintenance treatments based on rutting development analysis

To investigate the cost-effectiveness of different maintenance treatments of highways in Jiangsu Province, the historical pavement maintenance records, traffic load information and pavement performance data in the pavement management system （PMS） are recorded and analyzed. Compared with the growth model, the linear model, the logarithm model and the exponential model, the cubic model has higher regression accuracy R2 and it can capture the sigmoid shape of the deterioration curve. So it is selected to simulate the pavement rotting development. The benefit over cost ratio is calculated to quantify the treatment cost- effectiveness. The analysis results show that thin hot mix asphalt （HMA） overlays and micro surfacing are more cost- effective than the. other two treatments on light and moderate traffic roads. Hot in-place recycling and thick HMA overlays have much longer service lives and greater cost-effectiveness under heavy or extra heavy traffic.

Mixing ratio design of emulsified asphalt cold recycled mixture based on gyratory compaction molding

In order to study the application of gyratory compaction molding method in emulsified asphalt cold recycled mixture and optimize the relevant technical parameters, the study was carried out according to splitting strength, stability and water stability test;the design of the experiment involved changing gyration number, emulsified asphalt and water content, molded specimen temperature and other factors to analyze the volume parameters, mechanical properties and water stability. The results show that both the maximum dry density and dry and wet splitting strength ratio(DWSSR) of emulsified asphalt cold reclaimed mixture are improved by the rotary compacting method, while the porosity and the optimal dosage of water are reduced. Furthermore, with the increase of compaction times, the porosity and splitting strength index both change exponentially. DWSSR and porosity are consistent with quadratic functions. The use of gyratory compaction for 70 times at 25 °C and the optimum dosage of emulsified asphalt can be determined based on the splitting strength ratio. The high-temperature stability and water damage resistance of the pavement can be improved by the use of rotary compacting method effectively, and the early strength and road performance are higher than the regulatory requirements.

Review of emulsified asphalt modification mechanisms and performance influencing factors

In recent years,with the improvement of the requirements of road performance,modified emulsified asphalts with better performance has gradually replaced the emulsified asphalt and become the primary material for road maintenance.This paper introduces the modified emulsified asphalt materials commonly used in pavement maintenance projects,definitions and modified mechanisms of polymerized styrene butadiene rubber(SBR)modified emulsified asphalt,styrene butadiene styrene block polymer(SBS)modified emulsified asphalt and waterborne epoxy resin(WER)modified emulsified asphalt are summarized.The analysis focused on comparing the effects of modifiers,preparation process,auxiliary additives,and other factors on the performance of modified emulsified asphalt.In this paper,it is considered that the greatest impact on the performance of emulsified asphalt is the modifier,emulsifier mainly affects the speed of breaking the emulsion,stabilizers on the basic performance of emulsified asphalt evaporative residue is small;and when the modifier is distributed in the asphalt in a network,the dosage at this time is the recommended optimum dosage.Finally,this study recommends that in the future,the polymer-asphalt compatibility can be improved through composite modification,chemical grafting and other methods to continue to develop broader applicability and better performance of modified emulsified asphalt.

NOVEL SYNTHETIC METHOD OF LINGNINAMINETYPE ASPHALT EMULSIFIER

The slurry scaling with cationic emulsified asphalt, which is a new technique in highway construction, is rapidly extended at home and abroad. The technique should apply an excellent slow set cationic cmulsincr. Now, slow set emulsificrs are ligninamines which are synthesized by trimethylamine-epichlorohydrin route. Owing to high price and unstable quality, the extending of slurry sealing technique is affected seriously. We prepare the ligninaminc by a novel synthetic method. By the novel method, the cost of production is reduced by more than 30%, and the products have stable quality, high emulsifying function and broad adaptability for various asphalts. The novel synthetic method uses soda lignin, secondary amines and inexpensive aminating assistants as raw materials. The technological process of the method may use either one or two-step process, and the technological condition arc uncomplicated and easy to master.

Performance Characterization of CR/PU Asphalt for Potential Application in Assembled Fast-Repairing Engineering

Conventional repairing methods for asphalt pavement have some inconveniences,such as insufficient strength,and are typically time-consuming.To address these issues,this study proposes a new technological method to design and prepare a high-performance assembled asphalt concrete block for fast repair of the potholes.A series of composite modified asphalt binders with 10%crumb rubber(CR)and different dosages(0%,1%,3%,5%)of polyurethane(PU)are examined to determine the optimized binder.Subsequently,the corresponding asphalt mixtures are prepared for further comparison and assessment of engineering properties,such as moistureinduced damage,high-temperature deformation,and low-temperature cracking characteristics.The test results show that PU can significantly improve the high-temperature performance and hardness of(crumb rubber modified asphalt)CRMA binder;3%PU contributes allowing the resistance of CRMA mixture to moisture-induced damage at higher levels,particularly under water whole immersion;as 3%PU is added,the high-temperature rutting deformation resistance of the CRMA mixture increases significantly,and the low-temperature anti-cracking properties are also improved slightly.Therefore,the innovatively designed high-quality assembled fast-repairing asphalt concrete block is recommended as an appropriate option for highway maintenance.

改性剂对乳化沥青油水界面稳定性影响的分子模拟

【目标】为从分子层面研究乳化剂及改性剂自身结构对乳化沥青稳定性影响。【方法】选取以十六烷基三甲基溴化铵(CTAB)为代表的阳离子乳化剂和丁苯橡胶(SBR)与聚氨酯(PU)两种改性剂,利用分子动力学模拟软件分别构建乳化沥青与改性乳化沥青模型,通过模拟在乳化剂不同掺量下及掺加改性剂分子后,乳化沥青界面形成能、界面层厚度、扩散系数等参数的基础之上,分析乳化剂分子和改性剂特征基团倾斜角变化,研究改性剂对乳化剂分子在油水界面伸展性的影响,并利用宏观试验测试乳化沥青1 d存储稳定性,对模拟结果进行验证。【结果】在阳离子乳化剂CTAB分子掺量为15%时,界面稳定性最强;SBR和PU两种改性剂的引入均会对油水界面稳定性造成一定程度的影响;复配SBR与PU两种改性剂,再与CTAB分子相互作用时,油水界面稳定性能优于单一改性剂所产生效果。【结论】同时,乳化剂疏水尾链与改性剂特征基团在油水界面的倾斜角大小也可以有效表征其稳定性,即较大的倾斜角使界面抗破坏能力增强,有利于提高界面稳定性;模拟所得结论与宏观试验结果基本一致,验证了该模拟方法的可行性。

乳化沥青冷再生混合料强度特征与失效断裂演变机制研究进展

“双碳”背景下,将乳化沥青冷再生混合料作为冷拌路面材料已受到道路工程界的广泛关注.针对乳化沥青冷再生混合料设计与应用中关键技术问题的研究进展进行了综述,系统地汇总了乳化沥青冷再生混合料在施工控制、强度发展机理和损伤行为特征3个方面的研究成果.混合料制备工艺方面,总结了目前国内外乳化沥青冷再生混合料生产工艺的相关技术,阐述了乳化沥青冷再生混合料的材料特性、拌和工艺、成型方式和养生条件等对其施工和易性的影响;混合料强度发展机理方面,阐明了乳化沥青冷再生混合料在不同影响因素下的微观结构特征,凝练了材料强度形成过程中的内部界面行为;混合料断裂失效行为特征方面,归纳了研究断裂行为和断裂机理的理论方法和实验手段,探讨了乳化沥青冷再生混合料的断裂机制与疲劳特性.研究表明:构建全面的材料组成特性认知体系,利用多尺度手段揭示乳化沥青冷再生混合料强度形成机理,实时动态感知混合料疲劳损伤过程的阶段性演化规律,将对改善乳化沥青冷再生混合料的力学性能和延长冷再生路面的使用寿命具有重要意义.

聚氨酯改性乳化沥青冷拌重复再生集料路面修补料的试验研究

本文利用聚氨酯改性沥青技术和水泥浆处理技术弥补第二次重复再生集料的缺陷,将其再配制成冷拌重复再生集料路面修补料。通过黏附性试验、贯入试验、黏聚性试验、车辙试验、浸水马歇尔试验和冻融劈裂试验,分析了冷拌重复再生集料路面修补料的施工性能、早期强度、成型强度、高温稳定性、水稳定性等路用性能,研究结果显示聚氨酯改性乳化沥青冷拌重复再生集料路面修补料的各项性能均优于乳化沥青冷拌重复再生集料混合料,与聚氨酯改性乳化沥青冷拌天然集料混合料相差不大,缩短了路面修补后的养生时间,在实现建筑废弃物资源化利用的同时落实了“双碳”行动。

稀浆封层施工技术在公路路面养护中的应用

为研究稀浆封层技术在公路路面养护中的应用效果,结合实际项目,通过合理选择材料及湿轮磨耗试验、负荷轮粘砂试验、车辙变形试验,确定改性乳化沥青稀浆封层混合料的路用性能及最佳油石比为6.5%,经稀浆封层养护后,通过平整度、抗渗性、抗滑性测试检验了其养护效果。结果表明,路面的平整度、抗渗性、抗滑性比养护前分别提升了约25.20%、94.36%、43.84%,效果良好。

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.

微表处混合料耐久性影响因素差异性分析

为了分析微表处混合料耐久性的影响因素差异性,文章选取不同类型的乳化沥青、改性剂、集料级配和纤维,采用负荷车辙试验、湿轮磨耗试验和加速磨耗试验,系统评估了其性能,结果表明,SBR改性乳化沥青和玻璃纤维增强的混合料在抗车辙、耐磨耗和抗裂性能方面表现最佳;单因素方差分析显示,乳化剂类型和纤维类型对耐久性影响显著,集料级配对抗车辙性能影响显著。本研究为微表处混合料的选择和优化提供了理论依据。

项目级高速公路沥青路面长期养护策略分析

高速公路沥青路面长期养护策略的制定涉及路面状况检测分析、养护技术方案选择以及全寿命周期的经济效益比选等环节。文章以辽宁省某高速典型路段为研究对象,分析路面精细化检测诊断数据和历史数据,掌握了病害的成因和发展规律,提出养护策略组合,最终确定了合理的长期养护技术方案。

Fe_(3)O_(4) nanoparticles encapsulated in graphitized and inplane porous carbon nanocages derived from emulsified asphalt for a high-performance lithium-ion battery anode

In this work,C@Fe_(3)O_(4) composites were prepared through a typical template method with emulsified asphalt as carbon source,ammonium ferric citrate as transition metal oxide precursor,and NaCl as template.As an anode for lithium-ion batteries,the optimized C@Fe_(3)O_(4)-1:2 composite exhibits an excellent reversible capacity of 856.6 mA·h·g^(-1)after 100 cycles at 0.1A·g^(-1)and a high capacity of 531.1mA·h·g^(-1)after 300 cycles at 1 A·g^(-1),much better than those of bulk carbon/Fe_(3)O_(4) prepared without NaCl.Such remarkable cycling performance mainly benefits from its well-designed structure:Fe_(3)O_(4) nanoparticles generated from ammonium ferric citrate during pyrolysis are homogenously encapsulated in graphitized and in-plane porous carbon nanocages derived from petroleum asphalt.The carbon nanocages not only improve the conductivity of Fe_(3)O_(4),but also suppress the volume expansion of FesO4 effectively during the charge discharge cycle,thus delivering a robust electrochemical stability.This work realizes the high value-added utilization of low-cost petroleum asphalt,and can be extended to application of other transition-metal oxides-based anodes.

沥青路面黏层抗剪性能影响因素分析

为研究洒布量、温度与浸水时间对沥青路面黏层抗剪性能的影响,对3种乳化沥青:普通乳化沥青、SBR改性乳化沥青和SBS改性乳化沥青分别在不同洒布量下进行了直接剪切试验,并研究了不同温度和浸水时间对黏层抗剪强度的影响规律,结果表明:3种乳化沥青的最佳洒布范围均在0.6~0.8 kg/m^(2)。在最佳洒布量下,3种黏层在温度高于20℃时,复合试件层间抗剪强度随温度升高而下降的速率加快;常温浸水32 h后,3种乳化沥青的抗剪强度均减小至未浸水前的50%左右。综合对比发现SBS改性乳化沥青对温度和浸水的敏感性较小,建议优先选用SBS改性乳化沥青作为沥青路面黏层。

外加剂对乳化沥青基冷灌缝材料性能的影响

探究了减水剂(SP)、消泡剂(ALU)、早强剂(Z)对乳化沥青基冷灌缝材料性能的影响规律,确定出优化的乳化沥青基冷灌缝材料的外加剂组成。结果表明:随减水剂掺量的增加,灌缝材料的初始流动度减小,可工作时间延长,但其分离度增大,减水剂的最佳掺量为水泥质量的1.5%。随消泡剂掺量增加,灌缝材料的密度增大,但其掺量超过1.2%后,密度增加不明显,消泡剂的最佳掺量为水泥质量0.6%~1.2%。随早强剂掺量的增加,对灌缝材料的流动度、凝结时间、早期强度(1、3 d)影响较大,综合考虑,早强剂的最佳掺量为4.0%~5.0%。

面向城市沥青路面的养护技术及施工控制研究

针对沥青路面受自然环境和车轮磨损而质量下降的问题,论文提出采用一种沥青路面养护剂进行预防性养护,并选择高性能超薄沥青磨耗层施工技术进行施工。结果表明,强渗透养护剂材料和高性能超薄沥青磨耗层施工技术能够有效提高沥青路面的防水性能、抗裂性和水稳定性,具有一定的可行性和有效性。

高速公路沥青路面预防性养护工程中超薄磨耗层的应用研究

文章结合G75武罐高速公路路面提升整治工程,对改性NovaBinder沥青混合料制备的超薄磨耗层材料设计、施工方法以及使用效果进行详细研究与探讨。得出结论:改性NovaBinder沥青混合料制备的超薄磨耗层,厚度、宽度、构造深度、摩擦系数、渗水系数、平整度多项指标的检测数值均在标准规范之内,能够提升原始高速公路沥青路面的路用性能,优化路面行驶性能。

路用高聚物注浆材料的制备及性能研究

针对非开挖注浆修复技术的技术特点,提出了大体积空洞病害应采用膨胀型高聚物注浆材料,小体积空洞病害应采用微膨胀型高聚物注浆材料的技术观点。通过试验研究了催化剂、发泡剂用量对膨胀型高聚物注浆材料性能的影响以及催化剂、环氧树脂用量对微膨胀型高聚物注浆材料性能的影响。结果表明,膨胀型高聚物注浆材料B组份的配合比为胺基扩链剂用量5%、匀泡剂用量0.5%、催化剂A33用量0.5%和发泡剂水用量1.0%~1.5%。微膨胀型高聚物注浆材料B组份的配合比为胺基扩链剂用量5%、匀泡剂用量0.5%、催化剂T12用量0.2%、环氧树脂E51用量10%。

纤维沥青超薄罩面在旧水泥路面养护工程中的应用

为探究纤维沥青在旧水泥路面养护工程中的路用性能及工程应用情况,以碳纤维及玄武岩纤维为外掺剂进行纤维沥青混合料的路用性能试验,对比分析在不同纤维种类及纤维长度条件下,纤维沥青高温稳定性、低温抗裂性以及水稳定性等方面路用性能,结合空港商务区双安路养护工程在旧水泥路面养护工程中的应用效果,研究结果表明:(1)相较于传统AC沥青超薄罩面材料,添加纤维后的沥青混合料其动稳定度呈现明显增长趋势,其中,6 mm纤维较3 mm纤维对沥青混合料动稳定度的提高量更大;(2)低温弯曲小梁试验中,掺入6 mm玄武岩纤维的沥青混合料时间最大弯拉应变增幅最大,相较于传统AC混合料,其最大弯拉应变提高了19.3%;(3)水稳定性方面,掺入纤维后的试件浸水残留稳定度增幅为1.4%~4.0%,不同纤维种类对沥青混合料水稳定性的改善效果基本一致,但掺入纤维长度为6 mm时,其对水稳定性提升效果较3 mm纤维更优。

沥青路面就地热再生施工过程关键控制因素研究

为总结就地热再生沥青混合料应用中的常见问题,通过山西苛临高速公路就地热再生施工过程跟踪检测,得出施工过程中影响路面质量的两个关键因素,即再生混合料施工温度不稳定和旧混合料中粗集料存在压碎现象。文章确定了旧改性沥青路面路表面加热温度≤200℃、翻松裸露面温度≥100℃、再生沥青混合料摊铺温度介于140~160℃的温度控制范围,该技术要求可为就地热再生沥青混合料的施工及管理提供一定参考。