复合面层长寿命沥青路面力学响应分析

为了研究沥青混凝土(AC)与高延性混凝土(ECC)复合面层结构的长寿命沥青路面的力学响应,分析了复合面层在重复交通载荷作用下的应力与变形行为并进行相关性分析。结果显示,随着ECC层或基层厚度的增大,路面结构力学响应指标均逐渐减小。ECC层的加入显著提高了路面结构的承载能力,能更好地抵抗裂缝和车辙的形成,从而有效延长路面使用寿命。适当增加ECC层厚度可以进一步提高路面的抗变形能力,延缓反射裂缝的发展。

钢纤维混凝土复合面层耐磨地面施工技术应用

钢纤维混凝土地坪较传统的钢筋混凝土地坪存在更多性能优势,对钢纤维混凝土复合面层耐磨地面的施工方法及操作要点进行了总结。以兰州某扩能技改项目冲压车间施工为例,通过应用钢纤维混凝土替代传统混凝土,从工艺、成本和工期方面对两者进行了比较分析,结果显示,钢纤维混凝土的使用不仅加快了施工进度,减少了用量,还显著降低了工程造价,并缩短了工期;而且施工后的工程地面表面平整、线条清晰,满足了设计需求,获得了良好的观感和使用效果。

高强钢绞线网-聚合物砂浆复合面层加固砖墙的试验研究

高强钢绞线网聚合物砂浆复合面层具有高强、防火、聚合力强、无污染、施工简便等特点,是近年来国内外各类建筑加固补强工程所采用的新型应用技术。试验研究表明,对于混凝土构件,这种加固补强技术具有良好的效果。对采用该技术进行加固的15片砖墙的抗剪承载力试验进行了分析研究,结果表明,砖墙的抗剪承载力可以提高50%以上。该技术对于砌体构件同样具有良好的加固补强效果,可以在工程中应用。

浅谈钢绞线网—聚合物砂浆复合面层加固技术

针对钢绞线网—聚合物砂浆复合面层加固技术的加固原理和适用范围进行了阐述,总结了此种加固技术的应用优势,提出了此技术的施工流程和操作要点,以期使此种加固方法能够更好地应用于实际工程中。

高速公路收费站广场高性能刚柔复合面层应用研究

通过大量室内试验研究了高性能刚柔复合面层的力学性能及各项路用性能,分析了其应用于高速公路收费站广场的可行性。结果表明,高性能刚柔复合沥青面层具有良好的高温抗车辙性能、耐油蚀性能及优异的水稳定性,是高速公路收费站广场路面理想的结构型式。另介绍了高性能刚柔复合沥青面层在湖南省常祁高速公路收费站广场的应用实践。

粉土路基坡面复合面层护坡技术的面层材料特性

针对粉土路基边坡的坡面冲刷破坏和分层滑移破坏特征,提出一种融合玄武岩纤维加筋与聚丙烯酰胺固化作用,并集植草、抗冲刷、增稳多种功效的粉土路基坡面复合面层护坡技术。根据复合面层中不同面层的防护机制,开展对应面层材料的直剪试验、淋滤质量损失试验、渗透试验和毛细水上升试验,通过讨论面层材料中玄武岩纤维加筋量、筋长、聚丙烯酰胺掺量的变化与对应面层材料剪切变形、剪切强度、质量损失比、渗透系数、入渗量的关系规律,从材料角度分析获得玄武岩纤维的相对经济掺量、筋长与聚丙烯酰胺的相对经济配比及其对应材料指标。试验结果表明:复合面层材料相对粉土强度提高80%~150%,抗冲刷性能提高约200%,抗渗性提高约3个数量级;面层材料相对经济的配合比大致为玄武岩纤维筋长12mm、掺量0.4%,聚丙烯酰胺掺量1%;面层材料大幅改善了原粉土的强度、变形性能、抗冲刷性与抗渗性,3层复合面层材料将减少入渗、削弱侵蚀、提高强度3种功能融为一体。

复合材料面层夹层扁壳非线性精化理论及应用

考虑面层横向剪切变形以及横向剪应力在面层和芯层粘结处连续，应用Hamilton原理建立了正交铺设复合材料面层夹层扁壳新的非线性精化理论。在静力问题情形，控制方程和边界条件化简为用四个基本未知函数表述。作为理论的应用，分析了简支边界条件下正交铺设复合材料面层夹层圆柱壳和夹层球壳的非线性弯曲，得到了其挠度响应和层间应力响应。

半刚性面层复合材料浆体-集料界面显微硬度研究

为研究半刚性面层复合材料浆体-集料界面显微硬度及其影响因素,采用MH-5型显微硬度仪测定由不同细度填料和不同岩性集料配成的复合材料的浆体-集料界面显微硬度,运用扫描电镜(SEM)和能谱仪分析界面显微硬度存在差异的机理。结果表明,随着矿粉和水泥细度的增加,界面显微硬度增大;浆体-石灰岩界面显微硬度大于浆体-花岗岩的;填料细度不同,界面处生成产物存在较大差别;与石灰岩相比,浆体-花岗岩界面能够明显看到片状Ca(OH)2晶体的存在,C、Si的重量百分比明显偏高,导致界面粘结能力较弱。

基坑边坡装配式复合防护面层施工技术

基坑支护是对基坑侧壁及周边环境采用的支挡、加固与保护措施,对保证地下结构施工及基坑周边环境的安全性的影响不可忽视。本文以郑州市南四环至郑州南站城郊地铁二期车站主体结构边坡防护工程施工为背景,研制了土钉的钻孔与注浆技术、复合面层的铺设及搭接技术、可回收型边坡临时防护结构及其施工方法,为以后提升边坡在施工和使用的安全性经济性、优化边坡防护结构提供可行性方案。

基坑边坡装配式复合防护面层施工技术

基坑支护技术属于提高基坑整体稳定性以及实现对周边环境的支档、加固以及保护性的施工措施,其对于地下结构的施工以及周边环境的保护具备不可替代的作用。对此,本文以某工程为例,探讨基坑边坡装配式复合防护面层施工技术,希望可以为相关工作者提供帮助。

SMPM加固钢筋混凝土梁的耐火性能的数值模拟

采用ABAQUS程序对用新型加固技术(高强钢绞线网片—聚合物砂浆复合面层)加固后的钢筋混凝土梁的耐火性能进行了数值模拟。通过分析这种新型聚合物砂浆的热物理特性,提出了热传导系数和比热容的计算公式。对钢绞线和钢筋的温度变化以及梁的跨中挠度与试验进行了比较,结果表明,ABAQUS程序能够很好地模拟钢筋混凝土构件的受火过程,可以充分考虑温度场和位移场的耦合。

SMPM与其它加固方法的比较及RC构件加固程序简介

为了减少加固设计中的大量重复性工作,依据最新颁布的《混凝土结构加固设计规范》(GB50367-2006),用EXCEL编制了钢筋混凝土构件的加固程序。应用编制的计算程序,对6根不同截面的钢筋混凝土梁,同时采用钢绞线和碳纤维进行加固设计。对采用一层同梁宽的钢绞线或碳纤维加固后梁的抗弯承载力分析表明,钢绞线加固方法对承载力提高的幅度更大。结合对加固性能指标(使用空间的影响、防火、环保等)的综合比较,说明新型的钢绞线网片聚合物砂浆加固方法更符合经济、美观、实用的理念。

玄武岩纤维与聚丙烯酰胺加筋固化粉土剪切强度

针对粉质土路基坡面冲刷破坏与叠瓦状分层滑移的两大病害,提出一种粉土路基边坡固化加筋复合面层增稳抗冲刷护坡技术。开展了复合面层的直接剪切试验,讨论不同玄武岩纤维加筋量、筋长和聚丙烯酰胺掺量配比条件下复合面层材料的剪切变形和抗剪强度的变化规律,研究复合面层的增稳抗剪性能及玄武岩纤维的最优掺量、筋长与聚丙烯酰胺的最优配比。试验表明:复合面层最优配比为玄武岩纤维筋长12 mm、掺量0.4%,聚丙烯酰胺掺量1%,复合面层的抗剪强度能够满足护坡技术的要求。

Microstructures,mechanical and oxidation behaviors of C/C composites modified by NiAl alloy

Carbon/carbon composites modified by NiAl alloy were prepared using vacuum reactive melt infiltration methods with NiAl and titanium mixed powders as raw materials. The microstructures were investigated by scanning electron microscopy. The fracture behavior, infiltration and oxidation mechanism were further discussed. The results indicated that NiAl alloy exhibited good wettability on the C/C preform because a TiC reaction layer formed at the interface. Multi-layer（PyC/TiC/NiAl＋TiC） coating evenly and compactly distributed on the surface of the carbon fiber in tubular form. The penetration depth of molten NiAl alloys depended on the reaction between the PyC and titanium. The impact fracture was inclined to along the interface between the NiAl permeability layer and C/C matrix. Al_2TiO_5 and TiO_2 formed on the surface, while the interior multi-layer tubular structure partially remained after oxidation at 1773 K for 30 min.

SMPM加固过火梁的抗弯试验研究

SMPM加固技术即高强钢绞线网片—聚合物砂浆复合面层加固技术是一种新兴的加固技术,本文对3根RC梁进行受弯性能加固试验研究,BF—1为未过火对比梁,BFF—1为过火的对比梁,BFF—2为过火加固梁。通过对试验构件的破坏形态,裂缝分布,荷载-挠度曲线,极限承载力等方面的分析对比,表明普通RC梁在一般过火条件下,其抗弯承载力和刚度有一定程度的降低,而采用SMPM加固后的过火RC梁抗弯承载力和刚度有显著提高,可恢复到其过火前的水平。

Synthesis of Y_2O_3 particle enhanced Ni/TiC composite on TC4 Ti alloy by laser cladding

A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer were investigated. The composite layer has graded microstructures and compositions, due to the fast melting followed by rapid solidification and cooling during laser cladding. The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The size of TiC dendrites decreases with increasing depth. Y2O3 fine particles distribute in the whole clad layer. The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380, which is 4 times higher than the initial hardness. The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.

XPS AND UPS STUDIES OF THE INTERFACIAL INTERACTION IN Ni ZrO 2 COMPOSITE PLATING

The interfacial interaction existing in the Ni ZrO 2 composite plating has been investigated. The experimental results show that no new phases were formed in the interfacial regions between matrix Ni and ZrO 2 particles, but an orbital interaction through the mutual overlap of the d orbits does exist in the interfacial regions between Ni atoms and Zr 3+ ions.

A METHOD FOR PREDICTING BUCKLING LOADS OF COMPOSITE LAMINATED STRIPS WITH A SURFACE NOTCH

Surface notches lower the stiffness of laminated strips, so they lower the buckling loads of the laminated strips, too. In this paper a new method is proposed to predict the buckling loads of the laminated strips with a surface notch. The theoretical and experimental results show that the buckling loads decrease as the depth or width of the surface notches increase; when the stacking sequence of the laminated strips is [0°/0°/+ θ/-θ/0°/0°/+θ/-θ] s , the buckling load decrease as θ increases. It proves that the method is reliable and significant.

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.

Formation mechanism and control of aluminum layer thickness fluctuation in embedded aluminum-steel composite sheet produced by cold roll bonding process

The influences of rolling reduction and aluminum sheet initial thickness(AIT)on the thickness fluctuation of aluminum layer(TFA)of embedded aluminum?steel composite sheet produced by cold roll bonding were investigated,the formation mechanism of TFA was analyzed and method to improve the thickness uniformity of the aluminum layer was proposed.The results showed that when the reduction increased,TFA increased gradually.When the reduction was lower than40%,AIT had negligible effect on the TFA,while TFA increased with the decrease of AIT when the reduction was higher than40%.The non-uniformities of the steel surface deformation and the interfacial bonding extent caused by the work-hardened steel surface layer,were the main reasons for the formation of TFA.Adopting an appropriate surface treatment can help to decrease the hardening extent of the steel surface for improving the deformation uniformity during cold roll bonding process,which effectively improved the aluminum thickness uniformity of the embedded aluminum/steel composite sheets.