Noise Reduction in Pavement Made of Rubberized Bituminous Top Layer

In Greece more than 60,000 tn End of Life Tires are stockpiled every year often uncontrollable, causing severe environmental and other socio-economic negative impacts. Studies up to date are focused mainly on mechanical and physical characteristics of rubberized mixtures (based on cement, asphalt or soil) in which tire rubber is used either as alternative to natural aggregates or as additive. However, effect of tire rubber on noise reduction in rubberized bituminous layers, which is the main topic of present paper, has not been widely studied. In particular, this research paper is dealing with a sustainable use of tire rubber in asphalt pavement, leading to its generated noise reduction. An experimental pilot application has been conducted in the frame of a European Research Project, which has been implemented in a heavy traffic road section, cited outside Lamia city of Greece, (Vasilikon Street). The upper surface layer of the pavement has been made of rubberized bituminous mixture, produced by the wet process. Rheological characteristics of rubberized bitumen as well as basic properties of the implemented, rubberized bituminous mixture are presented. Moreover, measurements of noise level, deriving from vehicles’ motion, under operational conditions took place at the road section right after its implementation as well as after 8 months of its operation, while all data are presented in details. Results of the measurements on conventional and modified pavement sections are compared, certifying that rubberized asphalt layers can be not only environmentally friendly—since a category of solid wastes (worn automobile tires) is utilized—but also, addition of tire rubber particles in bituminous binder provides up to 3dB noise reducing bituminous mixtures and pavements, noise reduction that remains even after 8 months of road section’s operation.

Cavity noise sensitivity analysis of tire contour design factors and application of contour optimization methodology

Cavity resonance noise of passenger car tires is generated by interacting excitation between a tire structure and the fill gas (air), and generally lies in a frequency range of 200?250 Hz. As such, this noise is strongly perceived and may be a serious source of driver annoyance. Thus, many studies regarding the cavity noise mechanism and its reduction have already been conducted. In this work, a vibro-acoustic coupled analysis was conducted between a tire structure and air cavity. Using this analysis, we can more accurately simulate the tire noise performance in the region of the cavity resonance frequency. An analysis of the effects of variation of tire contour design factors was conducted, using design-of-experiments methods. Finally, a multi-objective optimization was performed using in-house codes to reduce the cavity noise level while minimizing the loss of other performances, such as diminished ride comfort and handling caused by the variations of contour. As a result of this optimization, an optimized contour shape was derived, which satisfied the multi-objective performances.

Modeling mechanistic responses in asphalt pavements under three-dimensional tire-pavement contact pressure

A three dimensional finite element program incorporating actually measured vertical tire-pavement contact pressure(TPCP) was utilized for modeling the mechanistic responses in asphalt concrete(AC) layers by simulating various vehicle motions:stationary and non-stationary(i.e.in acceleration or deceleration mode).Analysis of the results indicated the following items.1) It is critical to use the vertical TPCP as the design control criteria for the tensile strains at the bottom of the AC layer when the base layer modulus is lower in magnitude(e.g.≤400 MPa);however,when the base layer modulus is higher in magnitude(e.g.≥7 000 MPa),the horizontal TPCP and the tensile strains in the X-direction at the surface of the AC layer should also be considered as part of the design response criteria.2) The definition of "overload" needs to be revised to include tire pressure over-inflation,i.e.,a vehicle should be considered to be overloaded if the wheel load exceeds the specification and/or the tire inflation pressure is higher than the specification.3) Light trucks have more structural impact on the strain responses and pavement design when the thickness of the surfacing AC layer is thinner(e.g.≤50 mm).4) The acceleration of a vehicle does not significantly impact the AC surface distresses such as rutting at the top of the upgrade slopes or intersections;however,vehicle deceleration can dramatically induce horizontal shear strains and consequently,aggravate shoving and rutting problems at the highway intersections.Evidently,these factors should be taken into account during mechanistic stress-strain modeling and structural design of asphalt pavements.

Effect of dual and new generation wide-base tire assembly on inverted pavements

The conventional flexible pavements have been constructed such that the stiffness of the layer reduces with depth.The crust thickness becomes significantly high for heavy traffic corridors resulting in the consumption of large quantities of construction materials and also increasing environmental pollution.Inverted pavements with the aggregate interlayer(AIL)or stress absorbing membrane interlayer(SAMI)are considered to be one of the alternatives for thick conventional flexible pavements for heavy traffic corridors.The AIL or SAMI is placed between a stiff cement-treated base and asphalt concrete layer to function as crack relief layers.This change in the composition alters the behaviour of inverted pavements compared to the conventional flexible pavements.On the other hand,wide-base tires are being increasingly preferred by trucking industries due to increased fuel economy and cargo capacity.However,the effect of wide-base tires on the performance of inverted pavements is yet to be investigated.In this study,the 3D finite element(FE)models of inverted pavements considering different crack relief layers were developed,and load from dual-wheel and wide-base tires were applied.The stress-strain evolution in the various layers of inverted pavements was investigated and discussed in this study.The results indicated the higher stress and strains due to wide base tires compared to the dual-wheel assembly.Further,pavement with SAMI was found to result in lower stress and strains in the asphalt concrete layer compared to AIL pavements.

Determination of the Sound Absorption Capacity of Hydraulic Concrete Mixtures Added with Waste Tire Rubber

There are different types of pollutants that are harmful to the environment, including smog, chemicals that are dumped into rivers, scrap tires, etc. The latter have the particularity that it is not possible to recycle them to manufacture new tires. In the present work, hydraulic concrete plates added with waste tire rubber were manufactured to modify their sound absorption capacity. It was found that the rubber additions produce changes in the density of the material and in the sound absorption capacity. When the material is exposed to high-frequency sounds that correspond to high-pitched sounds, its absorption capacity increases. On the contrary, when the test frequency is low, that is, bass sounds, the sound absorption capacity decreases. The results obtained in this work suggest that the proposed mixtures are suitable for the possible manufacture of acoustic insulating shields.

Texturing and evaluation of concrete pavement surface:A state-of-the-art review

Concrete pavement is accompanied by two major functional properties,namely noise emission and friction,which are closely related to pavement surface texture.While several technologies have been developed to mitigate tirepavement noise and improve driving friction by surface texturization,limited information is available to compare the advantages and disadvantages of different surface textures.In this study,a state-of-the-art and state-of-thepractice review is conducted to investigate the noise reduction and friction improvement technologies for concrete pavement surfaces.The commonly used tests for characterizing the surface texture,skid resistance,and noise emission of concrete pavement were first summarized.Then,the texturing methods for both fresh and hardened concrete pavement surfaces were discussed,and the friction,noise emission and durability performances of various surface textures were compared.It is found that the next generation concrete surface(NGCS)texture generally provides the best noise emission performance and excellent friction properties.The exposed aggregate concrete(EAC)and optimized diamond grinding textures are also promising alternatives.Lastly,the technical parameters for the application of both diamond grinding and diamond grinding&grooving textures were recommended based on the authors'research and practical experience in Germany and the US.This study offers a convenient reference to the pavement researchers and engineers who seek to quickly understand relevant knowledge and choose the most appropriate surface textures for concrete pavements.

基于飞机滑水安全的沥青道面积水评价指标

沥青道面积水深度受横坡与轮辙变形共同影响分布复杂,是诱发飞机轮胎滑水事故的重要条件。当前,仅针对飞机起降运行给出污染跑道积水厚度范围,积水评价方式与实际运行环境脱节。基于轮辙横断面变形特征分析,提出一种考察飞机轮载横向累积作用概率分布的当量水膜厚度(EWT)指标。根据道面不同区域积水条件,分段建立轮胎滑水仿真分析模型,探讨滑水行为差异及轮辙积水影响机理,验证EWT的合理性与适用范围。结果表明:轮辙内部积水引起局部水膜增厚,当飞机滑行经过时,积水侵入轮胎底部,轮胎前缘轮廓模糊且接地面积降低;当前分段临界滑水速度减小,降幅与轮载累积作用概率正相关;轮辙变形导致轮胎“最不利”滑行位置自跑道边缘向中心线内移;EWT对应表征安全接地宽度更大,覆盖轮载累积作用概率约为平均水膜厚度(AWT)的2倍,滑水风险指标仅为AWT的36%~81%。所提评价指标克服了最大水膜厚度(MWT)取值过于严格的缺陷,更适用于机场管理实践,可为起降条件保障和滑水风险分级提供量化参照。

基于智能轮胎系统的实时路面辨识技术

在复杂和极限工况下,路面附着系数是进行轮胎受力分析和车辆动力学控制的重要状态参数。相对于模型估计的方法,智能轮胎技术能够将轮胎与路面的交互信息反馈给车辆控制系统。本文提出了一种将智能轮胎系统和机器学习相结合的车辆路面附着系数获取方法。首先,考虑行驶工况环境进行传感器选型,开发基于MEMS三轴加速度传感器的智能轮胎硬件采集系统,并采用简化硬件结构的无线传输模式。其次,通过采集不同路面上的实车实验数据进行车辆实验收集机器学习训练的数据集,并分析轮地关系及信号特征。最后,将CNN与LSTM两者的优势相结合实现了对加速度时序信号的特征学习。通过与其它神经网络模型训练结果的比较,验证了所提CNN-LSTM双通道融合神经网络模型的有效性和准确性。本文提出的路面辨识方案实现了实时道路识别的目标,硬件与软件架构和神经网络模型更适合车辆系统搭载,为车辆运动控制提供了实时准确的路面信息。

基于沥青路面纹理解构的轮胎/路面噪声预测方法研究

轮胎/路面噪声TPIN已成为城市环境噪声污染的重要组成部分,路面纹理是TPIN的重要影响因素。采用三维激光扫描技术获得路面点云数据,建立路面纹理三维模型,根据灰度共生矩阵(GLCM)、分形理论(FD)和功率谱密度理论(PSD)计算整体、宏观和微观纹理指标对路面纹理进行解构,建立基于纹理指标的TPIN线性回归和随机森林预测模型。结果表明:1)3种理论所计算的纹理指标可有效解构纹理,与TPIN有较好的相关性;2)车速在60 km/h时,TPIN与微观纹理的相关性更强,路面关键波长与噪声测试的轮胎波长有关;3)随机森林的预测精度高于单因素预测模型,最佳预测精度为R^(2)=0.9885,MSE=0.0004,预测效果较好。因此,可将路面纹理作为有效评价TPIN的方法。

考虑路面摩擦性能的自动驾驶汽车安全制动策略

针对现有自动驾驶研究大多忽略路面摩擦性能的问题,制备了5种不同级配的沥青混合料车辙板试件,基于Persson表面分形摩擦理论和轮胎‒路面三维有限元模型,求解沥青路面的动摩擦系数和附着系数,表征其摩擦性能,并使用Matlab/Simulink软件建立自动驾驶汽车的动力学控制模块,根据车辆期望制动减速度和道路摩擦性能逆向反推求解轮缸的制动压力值,实现自动驾驶汽车的制动过程。使用CarSim软件和Matlab/Simulink进行联合仿真,设定了下坡制动和曲线制动工况,分析了纵向坡度、弯道半径和道路超高等影响因素对自动驾驶车辆制动效能的影响。

大空隙沥青混合料配合比设计与性能研究

针对国省干线公路对抗滑、降噪功能需求日益提高的问题,通过对大空隙沥青混合料配合比设计与性能研究,分别选取了PAC-13型和PAC-10型大空隙沥青混合料,在试验路段分别采用了4组不同配合比进行施工,之后对铺筑后的试验路段进行了路用性能检测。研究结果表明:PAC-13型大空隙沥青混合料的最佳油石比为4.6%,PAC-10型大空隙沥青混合料的最佳油石比为4.8%;随着0.6~4.75 mm集料含量的增加,空隙率、有效空隙率和有效空隙率百分比均减小;PAC-13型试件路面容易形成丰富的宏观纹理,促进道路抗滑性能提升,使得在同样的环境条件下,其表现出更为优异的抗滑性能;PAC-10型大空隙沥青混合料的空隙率最大,空隙的曲折度最高,吸声效果最好。该研究采用的大空隙沥青混合料满足规范要求,能够为国省干线公路抗滑、降噪功能的提升提供参考。

掺废轮胎橡胶颗粒碎石封层黏结性研究

为提高废旧轮胎的再利用率,降低环境污染,将废轮胎橡胶颗粒等体积替换碎石制备新型橡胶颗粒碎石封层路面。通过橡胶颗粒表面的处理,确保橡胶颗粒碎石封层沥青‒集料间的黏附性,对不同集料粒径及橡胶掺量的碎石封层试件纹理特性进行评价,将橡胶颗粒掺量、集料粒径占比、脱落率、构造深度及摆式摩擦系数5个指标通过SPSS进行关联并评价,并以MMLS3试验模拟行车荷载,探究外界水温对其黏附强度的影响特性。研究结果表明:采用1.5%热沥青预裹覆的橡胶颗粒可有效改善碎石封层的集料脱落;脱落率与构造深度会伴随7.1~9.5 mm粒径占比及橡胶颗粒比例的增加有所上升;摆式摩擦系数与橡胶颗粒掺量增高呈现相反趋势;低温单因素对碎石封层集料脱落的影响大于高温和浸水,而水‒温耦合会使集料松散性加剧;整体而言,为确保碎石封层集料与沥青间具有较好的黏附强度,橡胶颗粒掺量与热沥青裹覆用量分别不宜超过50.0%、1.5%。

205/55R16低噪声轿车子午线轮胎的设计

介绍205/55R16低噪声轿车子午线轮胎的设计。结构设计:外直径629 mm,断面宽221 mm,行驶面宽度170 mm,行驶面弧度高10.2 mm,胎圈着合直径401.2 mm,胎圈着合宽度185.4 mm,断面水平轴位置(H1/H2)0.974,胎面采用对称花纹设计,花纹深度6.8 mm,花纹饱和度67.7%,花纹周节数72。施工设计:胎面胶配方采用溶聚丁苯橡胶和高分散性白炭黑,带束层采用2层3×0.3ST钢丝帘线,胎体采用1层1440dtex/2聚酯浸胶帘布,采用一次法成型机成型、液压硫化机硫化。成品轮胎性能试验结果表明,轮胎充气外缘尺寸、强度性能、高速性能、耐久性能和低气压耐久性能达到设计要求,通过噪声达到一级水平。

混合路面重载工况下使用的11.00R20载重子午线轮胎肩空问题的解决

针对11.00R20载重子午线轮胎在混合路面重载工况下出现的肩空问题建立系统分析模型,通过优化施工设计和调整材料分布来改进轮胎结构。通过模型、有限元分析、室内试验及实际使用来验证改进方向的有效性,即采取减小胎面胶厚度、胎肩垫胶厚度和胎侧厚度,优化三角胶过渡,胎体选用3+9+15×0.225ST钢丝帘线,胎圈部位调整为1层锦纶加强层设计等措施,使轮胎胎圈耐久性能显著提高,轮胎肩空问题有效解决。提出轮胎在结构改进过程中需建立系统性思维,针对失效部位改进的同时进行系统性调整,这对材料的使用寿命和最大化利用具有正向影响。

结构设计因素对半钢子午线轮胎噪声的影响

试验研究结构设计因素对半钢子午线轮胎噪声的影响。结果表明:降低三角胶高度、在一定范围内增大带束层角度和选择合适的带束层材料可在保持良好性能的前提下降低轮胎噪声。本研究可为半钢子午线轮胎结构设计提供一定参考。

低噪声柔性加固基层沥青路面结构设计研究

为减少沥青路面的不平整度,提升路面结构承载性能与行车舒适性,开展低噪声柔性加固基层沥青路面结构设计研究。首先,根据设计目标和工程需求,确定合理的级配范围;其次,基于路面结构层厚度力学分析结果,设计路面结构层厚度;最后,利用低噪声柔性加固基层技术设计沥青路面的各个层次结构。应用分析结果表明,应用文章提出的设计方法后,路面平整度均方差始终较低,可以有效改善沥青路面的平整度,保证路面性能与行车舒适性。

胎面花纹对轿车轮胎室内性能的影响

以205/55R1691V轿车轮胎为研究对象,通过在原胎面花纹的基础上增加横向沟槽设计并进行钢片雕刻,研究胎面花纹对轮胎外缘尺寸、静负荷性能、滚动阻力和室内噪声的影响。结果表明:胎面花纹变化对轮胎的外缘尺寸没有影响,对轮胎的静负荷性能、滚动阻力和室内噪声有较大影响;与原花纹轮胎相比,增加横向沟槽花纹轮胎的接地面积和滚动阻力增大,室内噪声降低。

全地面起重机用工程机械轮胎不同特征路面力学性能分析

建立了全地面起重机用385/95R25工程机械轮胎带花纹轮胎有限元模型,在验证了模型准确性的基础上分析轮胎在不同特征路面(平面路、横向凸台和纵向凸台)上的力学性能。轮胎充气外缘尺寸和接地数据有限元仿真结果与实测结果一致,表明有限元模型准确、可靠。有限元仿真结果表明:胎肩部位的应力集中于2^(#)带束层端点,应变极值也在此处,横向凸台条件下应力和应变较大;横向凸台条件下,1^(#)带束层帘线张力明显增大,胎体帘线张力在凸台接触区域减小;纵向凸台条件下,1^(#)带束层端点近纵向凸台的接触区域的帘线张力增大,胎体帘线张力变化不大;轮胎的包络刚度约为3000 N·mm^(-1);轮胎在破坏案例中的极限撕裂能为672 J,撕裂能指标对于配方设计有重要的参考意义。

基于路面图像分类识别的路噪主动控制方法研究

传统的吸声、隔声以及减震等降噪方法应用会导致车辆的重量也随之增加,且对低频率噪声降噪的效果并不理想,噪声主动控制技术能够在长波长的低频降噪中发挥不错的作用。对此,噪声主动控制技术应用比较广泛。本文研究基于路面图像分类识别的路噪主动控制方法应用,通过多种传感器应用,对车辆前方路面进行感知,识别前方路面,识别路面信息后输入到路噪主动控制算法中,为降低噪声,促进车辆智能化水平提升提供一些思路和参考。

精铣刨高性能水泥混凝土路面降噪效果测试与分析

高性能水泥混凝土路面(HPPC)与精铣刨工艺相结合,可使路面形成微露石子、纵向纹理的效果,从而降低胎噪。采用随车声强法测试SMA沥青路面、普通水泥混凝土路面和精铣刨高性能水泥混凝土路面在小型轿车和重卡两种车型、不同车速下的噪声值。测试结果表明:小型轿车、重卡在精铣刨高性能水泥混凝土路面的噪声值比SMA路面高1~2dB,且小型轿车在精铣刨HPPC路面的噪声均值落入噪声分区的中端控制区下游和低端容许区,降噪效果明显;精铣刨HPPC路面较其他两种路面能够更好地降低1250Hz以上的高频段噪声。