MPE改性剂在AC型沥青混合料中的应用

结合AC型混合料设计及施工,对添加MPE高分子聚合物的沥青混合料和常规SBS改性沥青混合料的室内试验、现场检测进行比较,分析其物理性能,研究MPE改性沥青混合料替代常规改性沥青混合料的效果.     

橡胶粉与SBS复合改性沥青高温性能试验研究

文章通过对30个不同配方的橡胶粉与SBS复合改性沥青高温性能指标的测试,研究了橡胶粉目数、掺量及SBS掺量对复合改性沥青高温性能的影响规律,结果表明:随着橡胶粉或SBS掺量的增加,复合改性沥青的针入度减小,软化点、弹性恢复及布氏黏度增大,高温性能明显改善,而20目橡胶粉比40目橡胶粉对复合改性沥青的高温性能更有利。最终优选出高温性能优良、技术经济优势明显的橡胶粉与SBS复合改性沥青配方:20目橡胶粉∶SBS∶基质沥青=16%∶2%∶82%。     

改性沥青材料在高速公路施工中的运用

文章结合工程实例,分析SBS改性剂含量的增加对沥青针入度、延度和软化点三大指标的影响,阐述了SBS改性沥青设计、制备与施工要点,并通过试验验证了SBS改性沥青在高速公路工程中的运用效果。     

再生SBS改性沥青与新SBS改性沥青老化差异性分析

文章采用薄膜烘箱老化试验,通过测试再生SBS改性沥青和新SBS改性沥青不同老化时间后的旋转黏度、针入度、软化点和延度,对两种沥青的老化性能进行了评价,并从老化规律、老化速度等方面对比分析了两种沥青不同指标间的老化差异性.结果表明:新SBS改性沥青和再生SBS改性沥青技术指标的差异性随老化时间增加而降低,再生沥青的总体抗...     

SBS改性沥青碎石封层质量控制与施工技术要点分析

SBS改性沥青同步碎石封层因具有较强的防水性和耐磨性,以及良好的抗老化性能和抗反射裂缝能力等优点,近年来被广泛应用于沥青路面的预防性养护中。本文结合S314线SBS改性沥青碎石封层施工现场情况,对SBS改性沥青碎石封层的施工质量控制、施工工艺与技术要点等进行了分析。     

SBS改性沥青机理分析与抗老化试验研究

文章通过红外分析、组分分析及DSC热分析阐述了SBS改性沥青的机理,分析了影响SBS改性沥青工程性能的主要因素,并通过抗老化试验研究了SBS改性沥青的劈裂强度与SBS改性剂用量之间存在的对应关系。试验结果表明,当SBS改性剂用量在合理范围内时,可提高沥青结构的抗老化能力。     

SMA—13改性沥青混合料在乐山港进港大道路面施工中的应用

通过SMA—13(沥青玛蹄脂碎石混合料)在乐山港进港大道施工中的应用,阐述了SBS改性沥青SMA的特性、材料选用、配合比设计以及混合料拌和、运输、摊铺、碾压等混合料的生产施工过程,并结合现场检测,分析了SMA的施工质量控制措施及施工中应注意的问题。     

高分子橡胶对浅色沥青结合料性能影响研究

本研究通过聚合物物理共混法将石油树脂、苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)和丁苯橡胶(SBR)等高分子橡胶加入到芳烃油中,利用高速剪切仪制备出均一的浅色沥青结合料。采用正交法设计试验方案,改变各组份掺量,研究SBS、SBR、石油树脂对浅色沥青结合料针入度、软化点、延度三大指标的变化规律,从而确定各组份的合理掺量范围,并检测浅色沥青结合料短期老化性能。试验结果表明:通过浅色沥青结合料与其他沥青的对比分析,浅色沥青结合料的性能均有所提高,为后续彩色沥青结合料研究提供了理论依据。     

速溶型SBS聚合物对橡胶改性沥青黏滞性能的影响研究

为了研究速溶型SBS聚合物对橡胶改性沥青黏滞性能的影响,分别采用掺量0%、5%、10%、15%及20%的橡胶改性沥青与掺量8%的速溶型SBS改性剂进行复配,成功制备出不同掺量的RPCSBS改性沥青,进行了不同温度、不同转速及不同橡胶粉掺量下的Brookfield黏度试验,并采用Brookfield黏度、施工温度及黏流活化能作为技术指标对不同掺量下RPCSBS改性沥青的黏滞性能进行了研究。试验结果表明,一定程度的橡胶粉掺入,会增加RPCSBS改性沥青的黏度、黏流活化能及施工温度。当橡胶粉掺量达到15%时,RPCSBS改性沥青的黏度、黏流活化能及施工温度均达到最大,不利于RPCSBS改性沥青的现场施工,故实际现场复配时,应精确控制橡胶粉和干法SBS改性剂的掺量,避免使用15%CR+8%SBS掺量。     

隧道掌子面岩体完整性系数快捷测试布置方法研究

为满足隧道施工期间掌子面围岩完整性快捷判定的需要,文章分析了岩块(体)波速现场快捷测试布置的原则,结合国内主流规范标准,采用对比法剖析了岩体结构面间距的划分标准,采用数学分析法研究了岩体完整性与结构面间距的量化关系。基于此,文章首次提出了岩块波速与岩体波速测试应遵守的声波对穿距离的控制标准Dr和Dm,并对测区、测点的布置方法及接收换能器系统进行了设计。结果表明,该测试方法在满足对整个掌子面和不同产状结构面全局把控的前提下,实现了测试快捷的目的。     

SBS改性剂对改性沥青性能的影响现状分析

SBS改性沥青是我国高速公路沥青路面最重要的改性形式,文章对比讨论了SBS改性剂种类、SBS改性剂结构以及原材料老化对SBS改性沥青性能的影响,并分析了某省90#进口沥青组分多年变化情况,说明了控制加工改性沥青原材料质量对确保改性沥青质量至关重要。     

SBS改性沥青混凝土路面施工工艺

SBS改性沥青施工在我国是一种新的技术。文章以同三国道主干线粤境广湛高速公路某段SBS改性沥青路面的施工实践为例,介绍SBS改性沥青的施工工艺及主要的质量控制要点,为类似工程提供参考。     

沥青路面面层-基层层间抗剪性能研究

为了对目前山区沥青路面常见的面层-基层滑移破坏问题提出有效的防治措施,文章通过室内试验,在AC-20混合料面层与半刚性基层之间洒铺基质沥青、SBS改性沥青、SBR改性乳化沥青,同时选择在20℃和52,7℃温度条件下,对试件进行45°斜剪试验,对比在不同材料、温度条件下的面层-基层层间抗剪强度。试验结果表明:层间经处理后的粘结强度均有不同程度的增加,增幅最大的是在层间洒布了SBS改性沥青,增幅最小的是在层间洒布了基质沥青;高温条件下,面基层间的抗剪切强度仅为常温条件下的8%~10%,说明温度对AC-20沥青层与半刚性基层间的抗剪切强度有很大的影响。研究结果可为增强面基层层间粘结力提供指导。     

A comparison of users’ characteristics between station-based bikesharing system and free-floating bikesharing system: case study in Hangzhou,China

The paper takes station-based bikesharing system (SBS) with docks and dockless free-floating bikesharing system (FBS) as two targets to dig out the relationship between users and use frequency of the services for each scheme, and how the relationship varies from scheme to scheme. To achieve this, studies are carried out focusing on three questions: “who are using these two bicycle services?”; “what are the factors influencing the use frequency of both bicycle systems?”; and “which specific level of the factors influencing the use frequency of both bicycle schemes?” To collect data from users, a survey was designed containing questions for user attributes and service experience and conducted jointly on-line and on-site at four locations with mixed land use in Hangzhou, China. Analysis results show that SBS and FBS have similar user structure but different factors influence use frequency. Based on analysis results, from the user perspective, SBS’s strength is to have good quality with low cost while FBS is more flexible and free to use. Finally, recommendations for SBS are to involve more technology to expand its range to aided bikes for senior citizens and open the access for a mobile renting system, whereas for FBS, it is critical to get government cooperation and for operators to add parking area restrictions into the cellphone application, and create an on-line platform where users can find all the free-floating bike information.

     

Analysis of Ground Response and Structure Stress Induced by PBA Method北大核心CSCD

The application of prefabricated tunnel technology has been become a new research field both in China and abroad. Based on the running tunnel between Yufuhe station and Wangfuzhuang station of Jinan rail transit line R1, a new prefabricated tunnel construction technology, the PBA method is presented. This paper makes a detailed discussion on section form, supporting scheme and construction process of the PBA method. In this study, 3D a new 3D numerical model for PBA method is presented by finite difference numerical simulation software Flac and the construction processes are modeled. The rule of ground surface settlement, ground deformation and structural stress caused by PBA method is studied in detail. Results show that the structure of PBA method can effectively control the deformation magnitude and scope. Stress concentration appears at the prefabricated connection parts and the reinforcement needs to check. The total assembled structure forms the load-bearing system after the completion of the lateral wall. The built-in depth of the precast pile and pile bottom grouting quality should to be ensured to control the displacement of the precast piles. The results of this study will be a useful reference for similar projects in the future. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Competitiveness prioritisation of container ports in Asia under the background of China’s Belt and Road initiative

ABSTRACT

The understanding of the competitiveness of different ports under the background of China’s “Belt and Road Initiative” (BRI) is critical for drafting appropriate plans and taking suitable actions to select the best port in the logistics supply chains. A novel Multi-Attribute Decision Analysis (MADA) was proposed for the evaluation of port competitiveness. In the developed MADA method, the interval Analytic Hierarchy Process and the projection method was combined for the evaluation of port competitiveness. Three container ports in Asia including Shanghai, Hong Kong, and Singapore were studied under the background of China’s BRI. The results demonstrate that the port of Singapore is the most competitive at the initial stage of China’s BRI, followed by Hong Kong and Shanghai in the descending order. The results were validated by sum weighted method and Technique for Order Preference by Similarity to an Ideal Solution method, and sensitivity analysis was also carried out. The competitiveness of the three ports in the next ten years were also studied with the consideration of the influences of China’s BRI, and the results reveal that Shanghai port can even exceed Hong Kong port and Singapore port if it can effectively take the advantage s of China’s BRI.     

密集行车动载铁路路基下锚索施工工法探索

文章针对密集行车动载铁路路基的施工特点,提出了密集行车动载铁路路基下锚索施工工法,并结合具体工程实例,阐述了该工法施工的工艺流程、技术要点及相应的质量控制措施,验证了该工法的优越性。     

对公路工程中黄土湿陷性问题的探究

文章通过对公路工程中黄土湿陷性的试验探究,在结合我国公路工程发展特点的基础上,提出黄土增湿陷性量计算的主要方法以及黄土增湿速率的基本方法,除此之外,并分析了在路堤填土小于或者大于相对高度的时候,对黄土地基的湿陷变形不予以考虑。     

钻孔灌注桩抽浆法清孔工艺研究

掌握好清孔工艺是控制好钻孔灌注桩成桩质量的重要步骤。文章基于钻孔灌注桩的基本施工流程,以钻孔灌注桩的抽浆法清孔工艺为研究对象,对其工艺流程、工艺控制、工艺要点和质量检测方法进行介绍,为钻孔灌注桩抽浆法清孔工艺的研究与发展提供参考资料。     

公路基层病害现场调研及处治技术应用

本文基于对水泥混凝土路面基层典型病害的调研分析,提出了适用于水泥混凝土路面基层病害处治的多种技术,着重介绍了压力注浆法的加固原理与技术参数,并结合工程实际应用,评价了注浆法的处治效果。