低噪声微表处设计及室内噪声测试研究

微表处技术具有良好的封水性能、抗滑能力及抗磨耗性能,能够修复轻微车辙,已经广泛应用于道路预防性养护工程中。其由于常温施工的特点,节能减排效果显著,是一种绿色环保型养护技术。然而,微表处路面的噪声较普通路面偏高,且在设计阶段目前尚无有效的噪声评价及控制方法,使得微表处路面在推广应用过程中受到一定限制。调整级配、减小集料粒径、添加纤维对降低微表处路面的噪声有一定益处。采用扫刷试验模拟行车过程,对所设计的低噪声微表处进行室内噪声测试,评价了不同级配微表处在不同车速下的噪声值,并评价了其路用性能。结果显示,所设计的低噪声微表处在满足路用性能的前提下,噪声得到了有效控制。     

微表处沥青混凝土抗磨耗性能影响因素

通过湿轮磨耗试验,对矿料级配、水泥含量及改性乳化沥青含量这3种微表处沥青混凝土抗磨耗性能的影响因素进行分析。试验结果表明:在级配范围内,矿料级配对微表处抗磨耗性能影响较小;湿轮磨耗值随着水泥含量和改性乳化沥青含量的增加而逐渐减小,并呈二次多项式分布,微表处抗磨耗性能相应增强;过多的水泥含量和改性乳化沥青含量并不能改善微表处混合料的抗磨耗性能,应通过试验确定水泥含量和改性乳化沥青含量。     

聚酯纤维-橡胶颗粒微表处混合料路用性能与降噪特性

通过常规拌合试验、粘聚力试验、负荷轮车辙试验,优化聚酯纤维和橡胶颗粒的掺量,进而采用低温SCB试验、剪切疲劳试验研究纤维橡胶微表处混合料的低温性能与耐久性,并选取轮胎振动衰减与室内轨道下滑试验,研究评价纤维橡胶颗粒微表处混合料的减振与降噪特性。结果表明,掺加橡胶颗粒能延长微表处混合料的拌合时间,但橡胶颗粒对微表处混合料的抗磨耗性能、低温抗裂性和抗车辙性能有负面影响;掺加0.2%聚酯纤维后,微表处混合料的路用性能与抗疲劳性能明显改善;聚酯纤维-橡胶颗粒微表处混合料比普通微表处混合料有更好的路用性能和减振、降低路面噪声的性能。     

微表处混合料性能及其应用

分析了微表处混合料配合比设计参数对混合料性能的影响,并通过湿轮磨耗试验和负荷车轮粘附砂试验对微表处混合料的性能指标进行了阐述,并论述了其在工程应用中应注意的问题,以推广微表处混合料的应用。     

微表处湿轮磨耗值影响因素的探究

本文通过湿轮磨耗实验,研究了微表处混合料在水浸泡条件下的抗磨耗性能,总结出沥青酸值和粉料掺加量两个显著的影响因素。简而言之,在低于某酸值条件下,即使增大沥青混合料的油石比,微表处混合料的耐磨耗性能仍然不能满足规范要求。此外,0.075mm粒径以下的矿粉掺量,也是微表混合料抗磨耗能力的另一重要影响因素。     

微表处混合料路用性能影响因素分析

为检验不同因素对微表处混合料路用性能的影响,制备混合料分别开展6 d湿轮磨耗试验和轮辙变形试验进行分析。试验结果表明,玄武岩的水稳定性和抗车辙性均优于石灰岩,水泥可以提高混合料的抗磨耗性能和抗车辙性能,掺入纤维后可提高混合料的抗车辙性能,不同矿料级配会影响混合料的抗水破坏性能和抗车辙性能,应结合实际情况合理选择。     

低噪音微表处路用性能影响因素分析

低噪音微表处是在常规微表处的基础上调整了级配和配比组成,添加了有机物橡胶屑作为空间结构填充和集料减震元素,使得它能够有效规避此前行车噪音过大的问题。针对油石比、掺水量、水泥、矿粉和橡胶屑掺量五个材料组成关键因素,文章根据湿轮磨耗试验和负荷轮粘砂试验分别研究分析了低噪音微表处抗磨耗性和抗水损性能的影响因素,明确了低噪音微表处组成设计的关键指标。     

快速开放交通型微表处的配合比设计及性能评价

根据北京市高速公路养护工作夜间施工光照弱、养生时间短的特点配制了一种适用于夜间施工的快速破乳型乳化沥青微表处混合料。该混合料的配置以可拌和时间为控制指标,首先优化了选材,确定了乳化沥青、水泥填料和水的最佳用量和配合比设计;然后对微表处混合料的黏聚力和湿轮磨耗值进行了检测和验证;最后通过实体工程应用对混合料的路用性能及工后使用效果进行验证评价。结果表明,在满足北京交通状态的可开放交通时间内,该种配合比设计的混合料具有较强的实用性。     

微表处路面噪声状况的检测与评价

微表处作为一种新型的路面预防性养护技术,在我国得到了广泛的应用,同时其较大的行车噪声问题也受到人们的普遍关注。为分析评估微表处路面行车噪声的特点及其对城市环境和居民生活质量的影响,基于微表处路面噪声产生机理,通过对代表性微表处路面的车内、外及路侧噪声进行测定,研究了微表处路面行车噪声与微表处路面构造深度、表面特性以及吸声系数之间的相关性,以期为进一步探索微表处路面减噪措施打下良好基础。     

掺加RAP的微表处混合料性能研究

为了多元化高效利用废旧沥青路面材料,并验证大掺量再生料(RAP)用于微表处混合料的可行性,试验研究了RAP掺量、乳化沥青用量等对再生料微表处混合料施工性能和路用性能的影响。结果表明,随RAP掺量增大,微表处混合料的施工和易性提高、粘附砂量增大,开放交通时间延长,但RAP掺量超过50%后,再生料微表处混合料粘聚力不符合JTG/T F40-02—2005《微表处和稀浆封层技术指南》要求。再生料微表处混合料的耐磨耗性能、抗车辙性能、水稳定性和低温抗裂性能随RAP掺量的增加而降低,因此用于填充车辙时,建议RAP掺量不宜大于40%。     

Evaluating skid resistance of different asphalt concrete mixes

At all stages of pavement life, the highway surface should have some sort of roughness to facilitate friction between car wheels and pavement surface. Skid resistance is a measure of the resistance of pavement surface to sliding or skidding of the vehicle. It is a relationship between the vertical force and the horizontal force developed as a tire slides along the pavement surface. The texture of the pavement surface and its ability to resist the polishing effect of traffic is of prime importance in providing skidding resistance. Polishing of the aggregate is the reduction in microtexture, resulting in the smoothing and rounding of exposed aggregates. This process is caused by particle wear on a microscopic scale. It is a common fact that the lower the skid resistance value, the higher the percentage of the traffic accidents, especially during the wet seasons. Having a low skid resistance value at an asphalt concrete surface might be attributed to one or more of the following reasons: (1) use of higher asphalt content than recommended by the mix design procedure, (2) the Marshall mix design procedure itself, (3) used aggregate gradation, and (4) aggregate quality. To evaluate these factors, a comparative study was performed to find the British Pendulum Skid Resistance Number for a number of mixes. These mixes included, an asphalt concrete mix using local aggregate at the optimum Marshall asphalt content, mixes with 0.5% and 1.0% asphalt contents higher than Marshall optimum asphalt content, a mix designed using Superpave design procedure, a mix with steel slag to replace 30% of limestone aggregate, and a mix with stone matrix aggregate gradation. It was found that the mix with 30% slag has the highest skid number followed by Superpave, SMA, and Marshall mixes, respectively. It was also observed that increasing the asphalt content above the optimal asphalt content value decreases the skid resistance of these mixes.     

低噪音玄武岩纤维微表处在养护维修工程中的应用

为改善传统微表处的噪声污染问题,结合甘肃G30线连霍高速永山段低噪音玄武岩纤维微表处工程,通过对原有路面病害调查、室内试验及现场施工检测等,分析低噪音玄武岩纤维微表处技术的配合比设计及降噪效果。结bs果tr表act明:I,n低or噪de音r玄to武co岩nt纤rol维th微e表pr处ob有le良好of的no降is噪e p效ol果lut及io抗n c水au损se性d能by, t在ra河dit西io地区有一定的适用性。ladYA关oonesna键il-ggyns词nsohiiasas:nneo低dfsbe噪oancrsoti音iaigolstie;n nf微iraoblefe表dpLruia处acvtneii;hoc配urne oo e合nseftf xu比edrpcifrt设sa eecosi计afs slwge;o as性hw,yma-io能snn fodg测iGoos3ooe试0rdbitannesosaGitls a tae n fnisrdbeu,e d frtiuheclimtsdiio cpcrnao op nesefsfrute rrscfutua ccamtiinnomdgnatrdieazecntetheesn rc aotlmilnooodsgn sa. y rnteahhsliryeso z trueaesgn shtcu heli,ten savmnesishdxmt o ihpgaransott iphcooeanrtrwtt atianohidne applicability inexi area.H Kwwmnm     

A simplified approach for mix design based on shape factors of coarse aggregates

The stability of granular materials and bituminous mixes increases with increase in dry density or decrease in voids in the mix. Therefore the proportions of materials in the mix are designed to obtain a desired gradation which yields maximum density. An investigation was carried out on gradation requirements of the mixes to obtain maximum density and stability values, using coarse aggregates with different shape factors. It is found that there is an optimum value of gradation index n of the gradation equation: p%=100 dⁿ/D, for an aggregate with a given value of angularity number. N. A. correlation between values of N and n has been obtained which can be used advantageously in mix design.     

Laboratory study on permanent deformation of foamed asphalt mix incorporating reclaimed asphalt pavement materials

For the purpose of investigating the effects of bitumen grade, content of reclaimed asphalt pavement (RAP) material and ageing of RAP, this paper presents the evaluation of permanent deformation of foamed asphalt (FA) mixes by using the dynamic creep test. The mix design of WC-20 was conducted based on the gradation requirement of FA mix and RAP aggregate size. Three parameters, creep strain slope (CSS), Intercept and secant creep stiffness modulus (SCSM), were used to analyze the test results. Mean comparison and multiple analysis of variance (MANOVA) reveal that bitumen grade significantly affects CSS, whilst content and ageing of RAP would have insignificant effect on CSS. High bitumen grade may help FA mixes on the reduction of susceptibility to permanent deformation. Test results reflect that variances of CSS, Intercept, and SCSM are large. There is a good exponential relationship between CSS and SCSM, however no correlation between CSS and air void is found. Comparison of test results between FA mixes and hot asphalt mixes exhibits that susceptibility and creep strength of FA mixes are better than those of selected hot asphalt mixes.     

某高层建筑室内声环境的改造分析

室内环境的重要性日趋显著,噪声是影响室内环境的主要因素之一。以西安市北郊某一高层建筑为例,从地下室水泵噪声的传播和室内空间尺寸两个方面出发,分析了引起住户室内噪声过大的原因,并通过减振、隔振及吸声处理等措施,对噪声污染进行了治理,并取得了良好的效果。     

微表处技术在沥青路面预防性养护中的应用

从施工材料选用、配合比设计试验、施工机械设备及原路面准备几方面介绍了微表处技术的施工准备工作,并着重对微表处施工工艺及施工工程质量控制进行了阐述,指出微表处技术具有施工快捷方便、开放交通快、节约能源、成本较低等优点,值得推广。     

纤维微表处最佳油石比的确定方法

近年来,微表处作为一种快速高效的路面修补技术,已得到越来越多的应用,但同时也发现了它的许多问题,如抗裂性差、填补车辙用的微表处本身容易出现车辙等问题。为了解决这一问题,许多研究人员采用在微表处中添加纤维的方法来改进微表处的性能,并确定出纤维微表处的最佳油石比,以期得到最佳性能的纤维微表处来解决普通微表处的不足。     

从降噪角度看隧道内路面结构的选择

通过实测的水泥路面与沥青混凝土路面噪声的对比,以及低噪音路面与水泥路面的吸声系数的对比,并结合各个路面的综合性能,分析了隧道内路面结构的选择,并且指出SMA路面结构更适合隧道路面。     

Performance based binder type selection using mixed integer programming technique

The rationale behind an asphalt mix design is optimizing the binder content for the desired aggregate gradation to satisfy the specified volumetric and strength requirements. The designed asphalt mix should be durable and cost effective. The mechanical behavior of a designed asphalt mix is affected by the traffic loading and climatic variations. To improve the mechanical properties of asphalt mixes, additives are added to the base asphalt binder. These binders are called modified asphalt binders. The objectives of the present study are to compare the performance of asphalt mixes with different binders by two different mix design methods and to optimize the asphalt binder type to achieve the desired performance. Two methods of mix design namely, Marshall and Superpave mix design methods are considered. The performances of asphalt mixes viz., tensile strength, moisture damage, densification and rutting resistance were compared. The results indicated a statistically significant difference in the optimum asphalt binder content from the two mix design methods. The Marshall method of asphalt mix design is found to yield lower optimal asphalt binder content when compared to the Superpave method of mix design. The moisture susceptibility and construction densification index of asphalt mixes designed using Superpave method were found to be significantly lower than that of the mixes designed by Marshall method. Optimization using a Mixed Integer Linear Program (MILP) indicated that the polymer modified asphalt binder outperforms the requirements of engineering properties when compared to other commercial binders used in the study.