Bamboo Fiber Modified Asphalt Mixture Proportion Design and Road Performances Based on Response Surface Method

In order to comprehensively utilize the remaining bamboo residue of bamboo products,this paper presents a research on recycling the bamboo fibers from bamboo residue for improving the performance of the asphalt mixtures.First of all,the basic performance parameters of sinocalamus affinis fiber,phyllostachys pubescens fiber,green bamboo fiber were tested and analyzed,and the optimal content and length were put forward.Then,the mix ratio design of the bamboo fiber modified asphalt mixture was further designed through the response surface method,and was verified the rationality of the mix ratio.Finally,the mixture specimens were made according to the experimental design mix ratio,and the high temperature,low temperature performance and moisture susceptibility of the bamboo fiber modified mixtures asphalt were tested.The results showed that the high temperature performance,low temperature performance and moisture susceptibility of bamboo fiber modified asphalt mixtures were improved compared with the performance of SBS modified asphalt mixture.When the length of bamboo fiber is 7.25 mm and the content of 0.22%,the road performance of the asphalt mixture was optimal.Consequentially,the decomposition of bamboo residue into bamboo fiber and its application in asphalt pavement can improve the reuse of bamboo waste,with remarkable environmental benefits and great promotion value.

A Comprehensive Evaluation of State-of-the-Art Deep Learning Models for Road Surface Type Classification

In recent years,as intelligent transportation systems(ITS)such as autonomous driving and advanced driver-assistance systems have become more popular,there has been a rise in the need for different sources of traffic situation data.The classification of the road surface type,also known as the RST,is among the most essential of these situational data and can be utilized across the entirety of the ITS domain.Recently,the benefits of deep learning(DL)approaches for sensor-based RST classification have been demonstrated by automatic feature extraction without manual methods.The ability to extract important features is vital in making RST classification more accurate.This work investigates the most recent advances in DL algorithms for sensor-based RST classification and explores appropriate feature extraction models.We used different convolutional neural networks to understand the functional architecture better;we constructed an enhanced DL model called SE-ResNet,which uses residual connections and squeeze-and-excitation mod-ules to improve the classification performance.Comparative experiments with a publicly available benchmark dataset,the passive vehicular sensors dataset,have shown that SE-ResNet outperforms other state-of-the-art models.The proposed model achieved the highest accuracy of 98.41%and the highest F1-score of 98.19%when classifying surfaces into segments of dirt,cobblestone,or asphalt roads.Moreover,the proposed model significantly outperforms DL networks(CNN,LSTM,and CNN-LSTM).The proposed RE-ResNet achieved the classification accuracies of asphalt roads at 98.98,cobblestone roads at 97.02,and dirt roads at 99.56%,respectively.

Technologies for Asphalt Pavement Surface Testing in Road and Bridge Construction

Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pavement,which will lead to the poor overall quality of road and bridge projects.Therefore,it should be applied reasonably.Advanced testing technologies are used to test the mixture quality,compaction,segregation,thickness,and other aspects of the asphalt pavement surface layer,so as to improve the quality of the asphalt pavement surface layer,and then improve the overall quality of road and bridge construction.Therefore,this paper mainly analyzes the technologies for asphalt pavement surface layer testing in road and bridge engineering construction.

New Method of Road Surface Identification in Anti-Lock Braking System

Based on the vehicle-road dynamic model, the road characteristic parameter, which depends on different types of road surfaces, is introduced and a new method of road surface identification for automotive anti-lock braking system (ABS) is proposed. According to the characteristics of vehicle-road dynamic model, a simple math resolution method of the model's factors is established. Only using the information of wheel speed, the vehicle reference velocity and the wheel slip ratio are estimated real-timely. And based on the wheel dynamic model, the road characteristic parameter is determined to identify the road surface for the determination of thresholds of ABS regulative parameters. With this new method, the road surface identification can be accurately obtained and calculation time is short that it can meet the ABS real time control need, and it also improves the performance of ABS.

Change Characteristics and Forecast Research of Road Surface Temperature on Huyu Expressway (Hubei Section)

In this paper,the monitoring data of road surface temperature,air temperature,wind speed,wind direction,relative humidity and precipitation from the automatic weather stations of Hurongxi,Hanyi,Wuhuang and Huanghuang on Huyu expressway from June 2013 to August 2014 were used to investigate the change characteristics of different sections' road surface temperatures in different seasons and sky conditions. The forecast models of the maximum and minimum road surface temperatures were established on different sections by statistical analysis methods,and the forecast results were verified. The results showed that the road surface temperature and air temperature of Hurongxi,Hanyi,Wuhuang and Huanghuang displayed obvious diurnal variation,but the difference between the road surface temperature and air temperature was larger. Compared with the other three sections,the maximum difference between the road surface temperature and air temperature on Hurongxi increased in winter and decreased in summer overall. The road surface temperature was close to air temperature on Hurongxi after sunset on sunny to cloudy and overcast in winter,while less than air temperature on Hanyi,Wuhuang and Huanghuang. The air temperature was less than road surface temperature on the four sections on rainy day and significant on Hurongxi. In summer,the air temperature was less than road surface temperature on the four sections under three sky conditions and the difference between them in afternoon was the biggest on sunny to cloudy and overcast. The road surface temperature was very close to each other among the four sections in January,while which was rising with the decrease of altitude in April,July and October. The forecast result of the road surface temperature was close to actual result on Hurongxi and Huanghuang,so which can be for reference. But there were some big errors between the forecast result and actual result in several timings on Hanyi and Wuhuang,so the forecast result should be corrected for actual business work.

Multi-objective genetic algorithm for the optimization of road surface cleaning process

The parameters affecting road surface cleaning using waterjets were researched and a fuzzy neural network method of calculating cleaning rate was provided. A genetic algorithm was used to configure the cleaning parameters of pressure, standoff distance, traverse rate and angle of nozzles for the optimization of the cleaning effectiveness, efficiency, energy and water con-sumption, and a multi-objective optimization model was established. After calculation, the optimized results and the trend of variation of cleaning effectiveness, efficiency, energy and water consumption in different weighting factors were analyzed.

Evaluation of Tactile Ground Surface Indicators Installed on Sidewalks Beside Ninghai Road of Nanjing Based on Fuzzy Comprehensive Evaluation

In recent years,tactile ground surface indicators have been vigorously constructed in all cities and towns in China,and the length of tactile ground surface indicators has been regarded as one of the standards for measuring urban civilization construction.However,there are many problems in the actual use of tactile ground surface indicators,and the construction of a large number of tactile ground surface indicators has not had a positive impact on the travel of the visually impaired.With the sidewalk of Ninghai Road in Nanjing,Jiangsu,China as the object of study,this study constructed an evaluation system of tactile ground surface indicators installed on the sidewalk beside a road and determined its weight,evaluated the tactile ground surface indicators installed on sidewalks beside Ninghai Road from the perspective of the visually impaired,using fuzzy comprehensive evaluation,and obtained the satisfaction of each indicator and analyzed the reasons of the indicator results.This set of evaluation system can provide basic ideas for the targeted evaluation of tactile ground surface indicators installed on the sidewalk beside a road based on different urban districts,different urban road grades,and different urban environmental conditions.

Developing a Durable Quiet Road Surface

Road traffic noise can have a significant impact on the quality of life for residents close to major road networks.One of the most effective measures for reducing the noise from road traffic,particularly on high-speed roads,is to ensure the use of a low noise road surface.Research on pavement construction and the measurement of its acoustic properties has shown that significant noise reductions can be achieved through the use of certain road surface types.However certain low noise road surfaces do not exhibit the desired durability associated with more traditional pavements,leading to costly and disruptive maintenance regimes.This article looks at the mechanisms involved in tyre/road noise generation and how these interact with various road surface properties including a brief overview of some common surface types.It then goes on to explain how these concepts informed the development of an asphalt surfacing material with enhanced durability and good acoustic performance without compromising safety.Progress in testing the resulting Premium Asphalt Surfacing System(PASS)is outlined,including the completion of a successful network trial.

Road Surface Condition and Monitoring System Utilizing Motorcycle(ROCOM)—System Development,Validation and Field Test

Motorcycles are the riskiest mode of travel in Malaysia,however motorcycles are also very sensitive to the road surface condition.Thus,by taking advantage of this,a system of software applications that analyses motorcycle motion and mapped out risky road sections was developed,i.e.ROCOM.The system consists of three major components,i.e.ROCOM Data Logger app,which utilizes a smart phone to collect acceleration data,ROCOM Risk Mapping app,which is a web-based application,and ROCOM Visual Tracking,which is a stand along software.ROCOM is able to detect adverse acceleration( >2g)or vibration on the road surface similar to the High Accuracy GPS Data Logging for Vehicle Testing(VBOX).Risk mapping validation along a section of the motorcycle lane along Federal Route 2 shows that not only ROCOM have the similar risk-mapping pattern,but its route tracking capability on the map is far superior that the VBOX.The pilot and field test results showed that ROCOM works best when mounting the smartphone on the motorcycle handle bar or basket,and it can detect various road anomalies with successful detection rate of 62%,with high detection rate when passing through uneven road surfaces.

A case study of environmental characteristics on urban road-surface and air temperatures during heat-wave days in Seoul

High road-surface temperature due to heat waves can lead to dangerous driving conditions such as tire blowouts and deformation induced by thermal stress on the roads. In this study, a Mobile Observation Vehicle dataset, with high spatial and temporal resolutions for the heat-wave episode that occurred on 16–17 August 2018, is used to understand environmental characteristics on urban road-surface and air temperatures in Seoul. This study demonstrates that the magnitude of urban road-surface temperature is dependent on the differences in incoming solar radiation due to screening of high-rise buildings in the Gangnam area, and is associated with the topographical features in the Gangbuk area. The road-surface temperature in the section of darker-colored asphalts was higher than that of lighter-colored asphalts, with a mean difference of 6.8°C, and both surface and air temperatures on the iron plate were highest, with means of 51.7°C and 35.1°C,respectively. In addition, during the water-sprinkling period, road-surface temperature was cooled by about 8.7°C(19%) compared with that in the period without water-sprinkling, but there was no significant change in air temperature. The current results could be practically used to improve roadsurface temperature prediction models for civil engineers or road managers.

Solution of pavement temperature field in“Environment-Surface”system through Green's function

In order to simplify the boundary conditions of pavement temperature field,the "Environment-Surface" system which considered the natural environment and pavement surface was established.Based on this system,the partial differential equations of the one-dimensional heat conduction in the pavement were established on the basis of the heat transfer theory.Furthermore,the function forms of the initial and boundary conditions of the equations were created through the field experiments.The general solution of the pavement one-dimensional heat conduction partial differential equations was acquired by using Green's function,and the explicit expression of pavement temperature field under specific constraint conditions was derived.For the purpose of analysis,the pavement temperatures in different seasons were calculated using the explicit expression of pavement temperature field,and the calculation accuracy was analyzed through the comparison between measured and calculated values.Then,the relationship between fitting accuracy and calculation accuracy of pavement temperatures was analyzed.The analysis results show that: the usage of "Environment-Surface" system simplifies the calculation of pavement temperature field; the relative error between calculated and measured values is generally less than 7% and is seldom influenced by seasons; there is a positive correlation between the calculation accuracy and the fitting accuracy of pavement surface temperature; high fitting accuracy would result in less error of pavement temperature prediction.

Sustainability of lime stabilized road subgrade in mountainous regions of Türkiye

In this paper the use of lime stabilized subgrade for low volume roads in two regions with high mountains and different frost penetration conditions in Türkiye was investigated in terms of design,performance,and cost.Pavements on unstabilized and stabilized subgrade were designed for two regions(Izmir and Van),covering all climate variations.The resilient modulus of the lime stabilized subgrade with different soil pulverization levels for non-freezing and freezing conditions were taken from a previous laboratory study.Frost effects were considered in pavement design using two different approaches,including limited subgrade frost penetration method and reduced subgrade strength method.Detailed application and evaluation were performed for all steps.Lime stabilized subgrades significantly reduced the thickness of base courses,and the benefit of lime stabilization was highly dependent on soil pulverization level.A detailed cost analysis on the unstabilized and stabilized cases found that the use of lime stabilization in the subgrade provided significant initial cost savings.Comparative analysis by using the AASHTO(1993)method and KENPAVE software,and quantity effect of soil pulverization level on the performance of low volume roads from a service life perspective,show that subgrade resilient modulus can be estimated.It is also possible to make correct performance estimation in the field.The results of the study show that lime stabilization is a good solution for low volume roads in the mountainous regions of Türkiye.

抢险车对92m跨度复合材料桁架桥动态响应的影响

为研究大跨径桁架式纤维增强复合材料(FRP)应急抢修桥梁成桥后的动力性能,基于导梁推送施工92 m跨度的FRP桁架桥模型,编制FRP桁架桥的车桥耦合算法,研究抢险车辆的车速、质量及路面不平顺对FRP桁架桥的跨中竖向位移、竖向加速度和关键杆件轴向应力等指标的影响.结果表明:路面越不平顺,车辆对桥梁结构的冲击作用越大,且路面等级对竖向位移的影响大于对关键杆件轴向应力的影响;车速为20~50 km/h时,车速变化对冲击系数影响较小,但车速超过50 km/h时,车速的影响逐渐增大;车辆质量对桥梁各项指标动力响应的峰值曲线呈线性增大趋势.当车辆质量为2.80×10^(4)kg,车速30 km/h时,最大跨中竖向位移为167 mm,未超过抢修桥梁位移限值(L/120),表明该桥梁的设计可以满足抢险的通行要求.

上面层改性沥青混合料低温性能综合对比评价

【目的】分析足尺路面试验环道所用7种上面层细粒式改性沥青混合料的低温性能。【方法】通过小梁低温弯曲、中梁线收缩系数和法国M2F梯形梁动态模量3种室内试验开展研究及相关性分析,并应用多指标试验结果的无量纲归一化赋权求和法进行综合对比评价。【结果】最大弯拉应变、应变能密度、线收缩系数、复模量和相位角均可作为改性沥青混合料低温性能的合理评价指标;对比改性沥青类型,采用低温延性强的SBS改性沥青制备的混合料低温性能最优,橡胶沥青混合料的次之,掺抗车辙剂能增强SBS改性AC类混合料的低温性能;对比矿料合成级配,SMA类的低温性能最优,SBS改性AC类中粗集料含量越低,其低温性能越好;多孔排水式高黏SBS改性PAC类具有优良的黏弹性和低温收缩性能。【结论】评价结果可为环道沥青路面低温性能长期监测对比提供参考。

基于车载LiDAR的交通标线自动提取方法研究

针对自动驾驶技术对高精度道路信息实时存储分析的需求日渐增大、道路点云数据冗余离散的问题,本文提出了一种从车载LiDAR点云数据中自动提取道路面、分类并矢量化交通标线的有效方法。首先,将点云数据中的非地面点滤除;其次,基于载体车辆的行车轨迹线生成伪扫描线实现道路面的提取;然后,构建一系列二维点云参考影像,利用点云强度等特征信息检测交通标线边界像素点及坐标,并去除离群值对交通标线进行分类细化;最后,对本文方法提取与传统方法提取的交通要素进行对比,实验结果表明,本文提取方法的准确度及效率都有了一定的提升。

基于改进YOLOv5的路面裂缝检测方法

针对现有裂缝检测模型体积较大且检测精度不高的问题,提出一种基于轻量化网络的无人机航拍图像裂缝检测方法。首先,使用MobileNetv3网络替代YOLOv5的主干网络,降低模型大小;其次,引入C3TR和CBAM模块提高网络表征能力,将损失函数替换为EIOU以提高模型的鲁棒性。实验结果表明,该方法在自制数据集上获得98.9%的精度,相较于原始YOLOv5提高1.2%,模型大小减小51.5%,检测速度提高37%。改进后的模型在精度、大小和速度上均优于Faster-RCNN等4种常见裂缝检测模型,满足了裂缝检测的实时性、轻量化和精度需求。

老化条件下聚丙烯纤维改性乳化沥青及其微表处混合料性能分析

为探究老化条件下聚丙烯(polypropylene,PP)纤维改性乳化沥青及其微表处混合料的性能,以丁苯橡胶(SBR)改性乳化沥青为黏结剂,PP纤维为改性剂,对不同老化条件下改性乳化沥青结合料蒸发残留物的流变性能展开研究,通过湿轮磨耗试验、车辙变形试验和低温劈裂试验探究5 d和12 d老化条件对微表处混合料路用性能的影响.研究结果表明:老化条件下改性乳化沥青结合料蒸发残留物的车辙因子和应力敏感性均随老化时间延长而增大,其高温抗车辙能力提升,而承受荷载变化下的弹性恢复能力下降.在2.5%应变幅值时,相较于未改性的乳化沥青,老化后PP纤维改性乳化沥青结合料蒸发残留物的疲劳寿命提高,抵抗疲劳损伤的能力提升明显.在0.2%PP纤维掺量下老化后微表处混合料的黏聚力提升11%,1 h及6 d湿轮磨耗值分别降低32%及25%,轮辙变形率降低46%,低温劈裂抗拉强度提升16%,微表处混合料路用性能得到提升.

轮胎/路表间水膜受力和排出特征及其受刻槽参数的影响分析

为研究轮胎作用下水泥混凝土路表水膜受力特征及其受刻槽的影响,采用SolidWorks和Ansys WorkBench,构建了轮胎-水膜-路表有限元模型,基于CFD控制方程和流固耦合理论,分析轮胎作用下路表水膜流动规律以及水膜厚度、行车速度、刻槽宽度、间距和方向对轮胎所受动水升力的影响。结果表明:轮胎迎水面所受动水升力随水膜厚度的增加而增大;当水膜厚度超过轮胎花纹深度后,动水升力增幅明显变大;增加路面刻槽宽度或减小刻槽间距,能够有效地降低轮胎所受的动水升力;在相同的刻槽参数下,路面横向刻槽的排水性能和对动水升力的降低幅度要优于纵向刻槽。

多源数据加权融合的城市建成区改进指数评估

针对多源数据提取建成区的研究大多集中在等权融合方向,缺乏考虑不同数据源包含的信息量差异的问题,通过多源数据加权融合方法对前人的城市建成区提取指数进行改进,以改善不同质量级数据直接融合导致建成区提取不准确的问题。首先,构建融合夜间灯光数据、NDVI数据、路网数据和POI数据的改进PREANI指数;其次,融入不透水面数据和温度数据构建无权指数UCI和有权指数WCI;最后,选择迭代法和动态阈值法提取建成区,并对3种指数分别进行评估。结果表明:改进PREANI的Kappa系数为0.80,UCI融入温度和不透水面数据将Kappa系数提高至0.83;WCI提取的建成区轮廓更准确,在增强城乡建成区细部对比、提升边缘地物区分能力方面表现良好,其Kappa系数、查全率、查准率和F1分数均在0.85以上。