塑料砂浆的性能研究

采用废旧PET塑料瓶作胶结料来制备塑料砂浆。研究了不同的PET与砂的比例、养生时间以及少量沥青的添加对塑料砂浆的物理和力学性质的影响。试验结果表明,塑料砂浆具备吸水率低,强度增长迅速的特性。随着塑料砂浆中含砂量的增加,其抗压强度与抗折强度增大。在室温条件下,塑料砂浆养生3h即可达到最终强度的90％以上;养生24h可达到最终强度。在塑料砂浆中加入少量的沥青,能够有效提高塑料砂浆的抗弯拉性能。     

Evaluation on Moisture Resistance of Asphalt Mixture with Active Mineral Powder

A new type of filler named 'active mineral powder' (AMP) was introduced and applied in asphalt mixture in order to improve the adhesive property of gneiss or granite aggregates and asphalt. The treated mixtures contained 2% AMP by weight of the total aggregates as filler. The moisture stabilization properties of various combined mixtures were analyzed using the adhesive test,Marshall stability and indirect tensile strength tests. Five frost-thaw cycles test was conducted to further investigate the effect of active filler on asphalt mixtures in the indirect tensile strength experiment. The results show that active filler improves the moisture stability of mixtures with gneiss and granite. The active mechanism of AMP was also discussed in this paper.     

应力吸收层沥青混合料的力学性能评价

为评价应力吸收层沥青混合料的力学性能,在室内试验测定沥青材料技术性能的基础上,基于马歇尔设计法,针对齐鲁70#沥青、稳定型橡胶改性沥青及应力吸收沥青设计了三种砂粒式应力吸收层沥青混合料。通过基本性能试验系统测定应力吸收层沥青混合料的动态模量,并建立动态模量和相位角的主曲线,主要探索了以齐鲁70#、稳定型橡胶改性沥青及应力吸收沥青作为胶结料的应力吸收层沥青混合料的力学特性。结果表明,稳定型橡胶改性沥青和应力吸收沥青作为胶结料用于应力吸收层均有良好的力学性能。     

羽毛纤维加筋沥青及沥青混合料的性能分析

在沥青混合料中尝试利用废弃羽毛替代传统纤维以便保护环境。在实验室内首先对羽毛老化温度进行了试验;其次对制备的羽毛沥青胶浆进行针入度、软化点和延度测试;然后在不同羽毛用量下,对羽毛加筋沥青混合料进行马歇尔设计,最后在最佳沥青用量下,对羽毛加筋沥青混合料开展性能试验。结果表明:羽毛可以承受普通施工温度而不老化;羽毛纤维能够改善沥青的针入度与软化点,但是羽毛含量超过1%将显著降低延度;羽毛含量每增加0.5%,最佳沥青用量将增加0.2%;羽毛可以改善马歇尔稳定度、抗水损害性能、抗车辙性能与抗分散性能。     

多孔沥青混合料粘弹塑性损伤模型

为合理描述多孔沥青混合料在中低温度外界荷载作用下的力学特性,基于增量型本构方程,采用Weibull损伤函数、广义Maxwell粘弹模型与D-P塑性模型,构建了粘弹塑性损伤模型．以此模型为分析手段,对不同温度和加载速率下的单轴压缩应力-应变曲线进行拟合,并分析温度与加载速率对模型参数的影响规律．分析结果表明:多孔沥青混合料粘弹参数随着温度的降低逐步退化成弹性参数,塑性模型中的体积模量和剪切模量也随温度呈现出明显的粘弹特性,塑性应变产生时对应的应变值与损伤应变阙值基本保持一致,温度及加载速率对于混合料的损伤扩展也有显著影响．构建的理论模型可以有效表征多孔沥青混合料在常温和低温下受荷时的力学损伤特性．     

干燥及饱和橡胶砂压缩和剪切特性

将废弃轮胎作为建筑材料应用在土木工程领域是对其回收处理最有前景的方法之一。为了研究轮胎橡胶颗粒改良砂土的效果,选取橡胶颗粒与福建砂的混合土为研究对象,研究了橡胶砂的压缩和抗剪特性,分析了橡胶含量与干湿状态对橡胶砂力学特性的影响,并建立了双曲线模型预测橡胶砂受剪过程的剪应力与剪切位移关系。结果表明：橡胶砂的压缩变形随橡胶含量增大而增大,饱和橡胶砂的压缩变形明显大于干燥橡胶砂;橡胶砂的剪应力剪切位移曲线表现出应变硬化特征;橡胶砂的抗剪强度与橡胶含量的关系不大;干燥试样内摩擦角随着橡胶含量的增大而降低,饱和试样的内摩擦角随着橡胶含量的增大而轻微升高;通过双曲线模型预测的剪应力剪切位移关系曲线与试验结果吻合。     

低温下沥青混凝土的拉伸变形特性

将数字图像测量系统替代传统的位移传感器采集系统应用于间接拉伸试验,得到沥青混凝土细观结构上的位移场分布和破坏形态。分析了粗骨料和细骨料结构沥青混凝土的低温抗裂性能,并研究了不同状态下材料的轴向、径向和体积应变特性以及泊松比的变化。数据分析表明:材料的弹性压缩和剪切膨胀与荷载作用历史紧密相连,反映了材料的结构性变形过程;沥青混凝土的低温开裂更多地依靠粒料与沥青结合料的界面黏聚力,良好的骨架结构是材料抵抗拉伸变形的前提。     

掺加旧料对温拌沥青混合料疲劳性能的影响分析

温拌再生沥青混合料是基于沥青温拌技术和再生技术发展而来的新型环保型沥青混合料.对掺加旧料（RAP）的温拌沥青混合料的疲劳性能进行了评价,分析了不同旧料掺量对疲劳性能的影响.疲劳试验采用小梁三分点加载方法,进行了旧料掺量为0%、15%、30%、45%以及60%的混合料疲劳试验.试验结果表明,旧料掺量越大,疲劳性能越差;30%为温拌沥青混合料的临界旧料掺量,此掺量为疲劳性能的＂性能拐点＂,超过此掺量后疲劳性能大幅衰减.     

Asbestos tailings as aggregates for asphalt mixture

To use many asbestos tailings collected in Ya-Lu highway,and to explore the feasibility of using asbestos tailings as aggregates in common asphalt mixtures,and properties of some asphalt mixtures were evaluated as well.X-ray diffraction (XRD),X-ray fluorescent (XRF),and atomic absorption spectrophotometry (AAS) were employed to determine the solid waste content of copper,zinc,lead,and cadmium.Volume properties and pavement performances of AC-25 asphalt mixture with asbestos tailings were also evaluated comp...     

The compaction characteristics of hot mixed asphalt mixtures

The quality of compaction is important to the performance of hot mixed asphalt(HMA) pavement. Most premature failures of asphalt pavement are concerned with poor compaction. Compaction characteristic of HMA mixtures were studied. Compaction tests were done with typical widely used HMA mixtures, including dense gradation asphalt mixtures with different nominal maximum aggregate size(AC13,AC20,AC25), and mixtures with different gradation(AC13, SMA13,Sup13 and OGFC13). HMA mixtures were sampled at different compaction temperature and Marshall blow numbers, varying between 60 and 175 ℃ and between 15 and 75 lows, respectively. The compaction characteristics of these mixtures were evaluated. The results showed that the Marshall stability and volumetric properties were significantly affected by the compaction temperature. Mixtures with the same NMAS but different type of gradation need different compaction energy to get the designed density.     

Simulation of rheological behavior of asphalt mixture with lattice model

A three-dimensional(3D) lattice model for predicting the rheological behavior of asphalt mixtures was presented.In this model asphalt mixtures were described as a two-phase composite material consisting of asphalt sand and coarse aggregates distributed randomly.Asphalt sand was regarded as a viscoelastic material and aggregates as an elastic material.The rheological response of asphalt mixture subjected to different constant stresses was simulated.The calibrated overall creep strain shows a good approximation to experimental results.     

Research on Alkaline Filler Flame-Retarded Asphalt Pavement

1 IntroductionDesign Specifications ofHighway Tunnel(JTG D70-2004)[1]specifies that all the highway tunnels may useconcrete pavement . When necessary the flame-retardedasphalt pavement may be used.The article explains whyall the accidents in Zhejiang highway tunnel occurred inconcrete pavements instead of in asphalt pavements .It isbecause the concrete pavement’s anti-skid coefficient andthe friction force decreased speedy. In addition, com-pared with concrete pavements ,the asphalt pavem…     

多孔安山岩在沥青路面中的应用研究

采用沥青浸渍集料、浸渍集料混合料、浸渍沥青混合料3种不同的沥青浸渍法和计算法分别确定沥青混合料的最大理论相对密度,并进行配合比设计,确定最佳油石比。对比分析了沥青混合料的各项路用性能,对未掺加抗剥落剂、掺加液体抗剥落剂和掺加消石灰的安山岩沥青混合料,分别进行了常规水稳定性能试验和汉堡车辙试验。结果表明:较之计算法,采用沥青浸渍法确定安山岩沥青混合料的最大理论相对密度进行配合比设计得到的沥青混合料各项路用性能更优;汉堡车辙试验可以很好地评价沥青混合料的水稳定性能,对于多孔安山岩,掺加消石灰为提高沥青混合料水稳定性能的最佳措施。     

废旧塑料改性沥青混合料动态模量研究

针对目前大量废旧塑料处置问题,尝试将其用于改性沥青混合料,以探索其在道路工程中使用的可能性.采用超市废旧高密度聚乙烯购物塑料袋,将其切碎后按照2%.5%和8%的掺量制作沥青混合料试件,采用三种试验温度在六种加载频率下进行动态模量试验,与未掺加塑料混合料的相应指标进行对比.试验结果显示在各个试验温度和加载频率下,掺加塑料屑的混合料动态模量普遍提高.掺加塑料与否对相位角指标的影响未呈现一定规律.在各个试验温度和加载频率下,2%塑料掺量混合料均具有较高的动态模量和相位角.     

南京江底盾构施工废弃砂土在同步注浆中再利用的适用性

依托南京长江新济洲供水廊道项目泥水盾构工程,针对江底粉细砂地层和岩石地层中泥水盾构施工产生的废弃砂土,研究其在盾构同步注浆材料中再利用的适用性。通过改变砂土地层弃砂的粒径分布,研究其对砂浆性能的影响;针对岩石地层产生的废弃砂土,研究其颗粒形状对砂浆性能的影响,并对岩层弃砂制备同步砂浆进行配比优化。结果表明：该工程砂土层弃砂可直接代替原配比中的砂进行再利用,岩层弃砂通过调整配比亦能满足工程要求;增大砂层弃砂细度模数和砂粒含量可改善砂浆的流动性,但砂土黏粒含量过大会使砂浆流动性变差、凝结时间缩短、强度降低;岩层弃砂颗粒表面越粗糙,所制备砂浆流动性越差,凝结时间越短。合适配比下,盾构施工废弃砂土可应用于同步注浆,砂浆配比应随废弃砂土粒径分布和颗粒形状的变化做出适当调整。     

The Characteristics of Asphalt Mixture in the System of Full Thickness Cold In-place Recycling

A new research method was proposed(A/S method) to study the components and properties of reclained asphalt mixture(RAP). The RAP was divided into two main parts, one was marked with A that included all the reclaimed old asphalt materials(including some parts of particle materials covered by asphalt), the other was marked with S which mainly included works soil in the road structure. The actual working conditions were simulated by this kind of new method, and the adaption between the RAP properties, A/S, and the content of cementitious materials were studied. The research indicated that the real working condition could be simulated effectively by means of A/S method. It was also showed that high content of cement could improve the overall performance of RAP significantly, but it would have a negative effect on the properties of RAP if the types and sizes of aggregate particles in RAP mixture were too single. The optimum water content and maximum dry density could not be regarded as the primary basis to evaluate the overall performance of RAP, when S=0 in the experiments, although the maximum density of samples was bigger than that with A/S=1/1, the samples were not strong enough and they were easy to collapse, which indicated that component design of RAP played a great role in improving the overall properties of RAP and the comprehensive tests should be considered to evaluate the stability of RAP. Low frequency load in high temperature environment had the negative effect on the overall stability of RAP, and factors such as the loading state of the materials, the hydration degree of cementitious materials, and the aggregate gradation in the mixture were the determining factors for improving the overall performance of RAP.     

废玻璃的经济回收与资源化利用

废玻璃是一种具有回收价值的固体废物,但是,目前废玻璃的垃圾填埋处置成本过高.本文建立一种废玻璃经济化的资源化处置方法.探讨经济且操作简单的废玻璃回收的方法.在工程应用研究中,以其作为骨料的基本材料,在处理过程中,采用简单的破碎和筛分.利用矩阵模型预测,废玻璃骨料粒径范围为1.18～4.75 mm,所占产品的比例为62％.结果表明：废玻璃作为骨料,浸出物的重金属的浓度极低,BOD5的浓度大约为20 ～ 35 mg/L.通过安全研究可知当废玻璃作为骨料回收时,废玻璃骨料回收过程是安全的.     

泡沫沥青温拌再生混合料试验研究

动态剪切流变试验评价不同拌和工艺下沥青结合料的老化程度,并提出老化因子量测指标。试验结果表明,泡沫沥青老化程度较低,沥青混合料路用性能受到影响。拟设计中粒式沥青混凝土HMA-AC-20、FWMA-20-RAP、FWMA-20同级配的三组混合料,进行性能检测。结果表明,泡沫沥青再生混合料可压实性好、抗水损害较好;泡沫沥青混合料抗疲劳开裂、抗低温开裂效果好;加入RAP料后压实沥青混合料的动稳定度提升很多,但仍然赶不上热拌沥青混合料。     

调和法在废旧沥青再生技术中的应用

采用沈大等5种废旧沥青混合料为原料,通过溶剂抽提法回收出旧沥青。经过对多种炼厂废料的大量实验比较分析,选定含高芳香组分A#剂与B#剂作为再生剂。由于在化学组成上(尤其是饱和分)具有互补性,可以将按一定比例混合作为复合再生剂。研究了复合再生剂加入量对针入度、软化点的影响,得到复合再生剂用量与道路沥青使用性能的关系方程,最终确定调和比例。使用这种再生剂可改善废旧沥青四组分之间的配伍关系,通过调和法成功使废旧沥青再生。再生后沥青质标完全满足重交通道路石油沥青质量标准(GB50092-96)的要求,而且在老化前后延度、针入度比等关键指标优于这个标准的要求。本方法与传统方法相比成本低,工艺简单,是一种废旧沥青再生新技术。     

细集料对沥青混合料体积和高温特性的影响

通过2种细集料(天然砂、机制砂)、2种级配(AC-13、Sup-12.5)沥青混合料的试验研究,分析了细集料类型和禁区对混合料体积指标和高温动稳定度的影响,结果表明机制砂更能有效提高混合料的高温性能,禁区的存在可有效限制细集料特别是天然砂的用量,以明显提高沥青混合料重载作用下混合料的动稳定度。而体积参数结果表明,Superpave设计方法中用固定空隙率4%标准来确定最佳沥青用量的方法是否合理有待进一步验证。