Optimization of polyurethane-bonded thin overlay mixture designation for airport pavement

This research explored the application potential of PUM thin-overlay technology on airport rapid maintenance. The rapid curing process of polyurethane binder determines the limited time window for mixing and construction of polyurethane-bonded mixture (PUM), which presents significant difference with hot-mix asphalt (HMA) technology. Therefore, this research investigated and optimized the mix design of PUM for airport thin-overlay technology based on its thermosetting characteristics. First, limestone and basalt were comprehensively compared as an aggregate for PUM. Then, the effects of molding and curing conditions were studied in terms of mixing time, molding method, molding parameters and curing temperature. Statistical analysis was also conducted to evaluate the effects of gradation and particle size on PUM performances based on gray relational analysis (GRA), thus determining the key particle size to control PUM performances. Finally, the internal structural details of PUM were captured by X-ray CT scan test. The results demonstrated that it only took 12 hours to reach 75% of maximum strength at a curing temperature of 50 °C, indicating an efficient curing process and in turn allowing short traffic delay. The internal structural details of PUM presented distribution of tiny pores with few connective voids, guaranteeing waterproof property and high strength.     

通用机场水泥混凝土道面评价研究

跑道是机场的重要基础设施。机场道面性能的优劣直接影响着飞行的安全。按照机场运行安全管理有关规定,机场道面每五年要进行一次综合性评价,以确定该道面是否达到安全运行要求。鉴于此,本文以通用机场的训练机场跑道作为研究对象,以道面损坏调查结果为依据,对该机场道面从平整度和结构承载力两方面进行评价,根据评价结果结合机场实际运行情况提出适应该机场的道面维护建议。     

民用机场跑道道面检测与评价体系研究

根据机场跑道道面特性,选取相关评价指数及计算方法,制定了指数基础数据的检测方法,提出了适用于民用机场飞行区道面的综合评价体系,以西安咸阳国际机场为例进行了验证,结果表明:该评价体系较全面覆盖了道面使用的各类特性,能充分反映跑道道面的性能。     

机场混凝土道面新型胀缝材料

分析机场道面对胀缝材料要求及胀缝材料应用现状，结合机场道面工程的特点对国内现有胀缝材料的选用进行分析，并根据对比试验验证结果，提出了适合机场混凝土道面要求的新型胀缝材料。     

User costs in pavement construction and rehabilitation alternative evaluation

The decision-making processes used by many state transportation agencies in US and Canada for selecting a strategy for pavement rehabilitation primarily depend on initial construction and maintenance costs for identifying the most economically efficient pavement rehabilitation alternative. While this approach is appropriate for optimally allocating increasingly limited funds in the face of increasing investment backlog, it is not economically efficient because it does not account for user costs. Despite a significant body of research, the state transportation agencies are hesitant to include user costs in their pavement life-cycle cost analysis processes because of a lack of availability of standard method of calculating user costs. This article presents the results of a study conducted to review the pavement alternative selection processes used by the Ohio Department of Transportation and recommend ways to include user costs in the decision-making process. Incorporating user costs in the decision-making processes right from project-development phase will help transportation agencies stay focused on the customer and minimise overall impact of rehabilitation of the highway system.     

机场道面混凝土抗折强度抽样检验

本文论述了当前机场道面混凝土抗折强度的抽检方案（32，－0．30）的参数选择与计算过程（合格质量μ1＝ff标＋1．04σ，极限质量μ2＝ff标＋0．506σ，α＝0．05，β＝0．10）。要求样本强度均值符合fn^-≥ff标＋0．74s。对于高性能道面混凝土，要求强度高于设计规定的ff标的概率达到95％。建议抽检方案约（32，－0．34），（μ1＝ ff标＋1．645σ，μ2＝ff标＋1．04σ，α＝0．03，β＝0．07）。要求样本强度均值符合fn^-≥ff标＋1.30s。     

机场道面混凝土抗折强度抽样检验(续)

本文论述了当前机场道烦混凝土抗折强度抽检方案（32，－0．30）的参数选择与计算过程（合格质量μ1＝ff标＋1．04σ，极限质量μ2＝ff标＋0．506σ，α＝0．05，β＝0．10）。要求样本强度均值符合fn^-≥ff标＋0．74s。对于高性能道面混凝土，要求强度高于设计规定的ff标的概率达到95％。建议抽检方案，（32，－34），（μ1＝ff标＋1．645σ，μ2＝ff标＋1．04σ，α＝0．03，β＝0．07）。要求样本强度均值符合fn^≥ff标＋1．30s。     

机场混凝土道面施工技术

以毕节机场道面施工技术为例,系统阐述了机场道面施工工艺流程,着重对模板制作、下承层检验、干硬性混凝土摊铺、振动行夯整平等工艺进行了论述,以期对类似工程起到一定的参考和借鉴作用。     

机场混凝土道面新型封缝材料

在分析国内外机场道面封缝材料应用现状的基础上，结合机场道面工程的特点对国内现有的密封材料的现状进行了分析，并根据对比试验证明验证结果，提出了适合机场混凝土道面要求的新型封缝材料。     

机场自密实道面混凝土微观分析

对某机场采用的掺粉煤灰的自密实道面混凝土的内部结构进行检验与分析，并与传统的未加矿物微细掺料的干硬性道面混凝土进行对比，孔结构与过渡层结构有明显的改善，从而证实了这种自密实道面混凝土比上述传统的道面混凝土具有较高的强度和耐久性，并能够具有较长的使用寿命。     

沥青混合料摊铺要点

从摊铺机结构和运行参数入手,探讨了沥青混合料摊铺要点,分别介绍了摊铺机结构参数调整和选择方法,并对摊铺机运行过程中各参数的确定及提高摊铺质量的具体措施进行阐述,以期指导实践。     

Laboratory and field evaluation of asphalt pavement surface friction resistance

Pavement surface friction is a significant factor for driving safety and plays a critical role in reducing wet-pavement crashes. However, the current asphalt mixture design procedure does not directly consider friction as a requirement. The objective of this study was to develop a surface friction prediction model that can be used during a wearing course mixture design. To achieve the objective, an experimental study was conducted on the frictional characteristics of typical wearing course mixtures in Louisiana. Twelve wearing course mixtures including dense-graded and open-graded mixes with different combinations of aggregate sources were evaluated in laboratory using an accelerated polishing and testing procedure considering both micro-and macro texture properties. In addition, the surface frictional properties of asphalt mixtures were measured on twenty-two selected asphalt pavement sections using different in situ devices including Dynamic Friction Tester (DFT), Circular Texture Meter (CTM), and Lock-Wheel Skid Trailer (LWST). The results have led to develop a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend polish stone value, gradation parameters, and traffic, which is suited in checking whether the selected aggregates in a wearing course mix design would meet field friction requirements under a certain design traffic polishing.     

机场道面混凝土耐久性研究

针对我国寒冷地区机场道面混凝土以及一些高等级公路路面混凝土耐久性不良的现象,在分析其原因的基础上提出了相应的防治措施,对不同类型的道面混凝土的耐久性进行对比试验研究.试验结果表明:掺加粉煤灰或引气减水剂的道面混凝土,其抗冻、抗渗、耐磨性能均有较大提升,为高性能道面混凝土.     

Laboratory evaluation of fatigue characteristics of recycled asphalt mixture

This paper presents the results of a laboratory study of evaluating the fatigue characteristics of hot-mix asphalt (HMA) mixtures using different testing methods. In this study, the fatigue performance of HMA mixtures was evaluated with the Superpave indirect tension (IDT) tests and beam fatigue test. The HMA mixtures containing 0%, 10%, 20%, and 30% of recycled asphalt pavement (RAP) were plant prepared with one source of aggregate, limestone, and one type of binder, PG 64–22. The fatigue properties tested included indirect tensile strength (ITS), failure strain, toughness index (TI), resilient modulus, DCSE_f, energy ratio, plateau value, and load cycles to failure. The results from this study indicated that both Superpave IDT and beam fatigue tests agreed with each other in ranking the fatigue resistance of mixtures when proper procedures were followed.     

机场道面合成纤维混凝土收缩变形性能

针对机场道面混凝土可能所处的环境,研究了不同养护条件下改性聚酯纤维混凝土和聚丙烯纤维混凝土的收缩变形性能,并对2种合成纤维混凝土的收缩变形性能进行了比较.结果表明,在各种养护条件下,掺入合成纤维均有利于减少混凝土的收缩,在相同掺量下,改性聚酯纤维的抗收缩性能优于聚丙烯纤维.     

机场道面引气混凝土性能试验研究

机场道面混凝土是一种干硬性混凝土,与一般建筑工程使用的混凝土有较大区别.着重从含气量对机场道面混凝土的工作性和强度及抗冻性等方面的影响进行了试验.研究表明:抗折强度随含气量的增大而减小,但在3.5%～5.5%区间时,抗折强度下降较平缓;混凝土抗冻性随含气量的增大而提高,当含气最大于3%时,能够满足道面混凝土抗冻性要求.     

Laboratory evaluation of smoke detectors for use in underground mines

Laboratory experiments were conducted to determine the responses of a prototype smoke detector and a commercially available photoelectric smoke detector to smoke particles generated from various combustion sources. The prototype smoke detector combines optical scattering measurements with ionization chamber measurements in order to reduce/eliminate nuisance alarms due to the presence of airborne dusts or diesel exhaust particles. The commercially available smoke detector is designed for use in harsh environments where airborne dust represents a major problem due to both nuisance alarms and detector contamination. In the experiments, the responses of the two detectors were measured when exposed to smoke particles from the exhaust of a diesel engine and from a variety of fire sources, including wood, coal, styrene butadiene rubber, and No. 2 diesel fuel. For the solid fuels, data were obtained for both smoldering and flaming combustions. This report describes the experiments, their results, and the use of these results as they apply to early-warning fire sensors capable of the rapid and reliable detection of fires in atmospheres that may or may not be contaminated by either airborne dust or the products produced from diesel engines.     

机场道面再生混凝土配制与施工

机场道面翻修、改(扩)建工程会产生大量的废弃混凝土,如何利用废弃混凝土作为再生骨料,配制道面再生混凝土,满足机场道面工程设计与施工要求,采用掺加优质粉煤灰和高效外加剂的"双掺"技术路线,进行道面再生混凝土配合比设计。室内试验表明,所配制的道面再生混凝土性能优于普通道面混凝土,现场施工实践也表明,所配制的再生混凝土可以用于机场道面工程,是一种新型绿色环保混凝土。     

机场道面新型碱矿渣快速修复混凝土研究

利用地聚合物的快速固化特性,研制一种无熟料新型碱矿渣机场道面快速修复混凝土,探讨了不同激发剂类型、矿渣掺量及养护温度等对混凝土强度的影响.通过施工现场试铺检验表明,利用新型碱矿渣混凝土快速修复的道面,4h抗折强度可达3.03 MPa,抗压强度达到25.19 MPa,且表面性能优异,满足机场道面抢修要求.     

机场道面多余物的来源与控制

对机场道面多余物的种类和来源进行了分析,从日常保障、多余物数据统计、宣传与合作等方面,提出了机场道面多余物的检查与管理措施,以有效预防多余物的产生,从而保障飞行安全。