Modelling the performance of pavement marking in cold weather conditions

Inadequate and poorly maintained pavement markings are considered to be one of the largest contributing factors to fatal motor vehicle crashes. As a result, it is essential to apply the appropriate pavement marking material for all weather conditions in order to increase public safety and reduce motor vehicle crashes. Building a strategic plan to renew and re-stripe pavement marking is receiving increasing interest from companies/authorities that manage the pavement marking in order to reach the most cost-efficient management plan of the available pavement marking materials. The objective of this paper is to develop pavement marking performance models that predict the condition of different marking materials under various service conditions including weather, traffic and snow removal plans. The developed models are validated and the results show that the average percent validity varies from 87% to 99%. Marking performance is assessed using a condition rating scale, which numerically ranges from 1 to 5 and linguistically from excellent to critical, respectively. Deterioration curves are developed that assess the condition of the pavement marking based on the developed models. They are expected to benefit academics and practitioners (municipal engineers, consultants, and contractors) to prioritise inspection, stripping, and re-stripping planning for various pavement markings.     

Fuzzy Representation of Pavement Condition for Efficient Pavement Management

Abstract: Many government agencies and private consulting companies manage large pavement networks in terms of infrastructure condition assessment and maintenance planning. Efficient pavement management is supported by pavement management systems (PMSs), which includes models for pavement condition assessments considered “valuable” by agency's engineers. The objective of this article is to define a pavement condition model able to overcome surveyors’ subjectivity in rating distresses and thus provide meaningful pavement conditions for the agencies to employ in project planning. The article proposes a fuzzy inference model for calculating pavement condition ratio (PCR) specifically tailored on the Alabama Department of Transportation Pavement (ALDOT) guidelines and policies. Applied to several surveyors’ ratings, the proposed model has the ability to smooth distress extent differences among surveyors producing PCR values within acceptable range of variability. The proposed approach has the intention of not only enhancing pavement condition characterization but also to exploit the opportunity made available by automation in the collection and interpretation of pavement data which are anyway characterized by an inherent subjectivity.     

Integration of geographic information systems and computer vision systems for pavement distress classification

The main objective of this research work was to investigate the potential of integration of geographic information system (GIS), global positioning system (GPS) and computer vision system (CVS) for the purpose of flexible pavement distresses classifications and maintenance priorities. The classification process included distress type, distress severity level and options for repair. A system scheme that integrated the above-mentioned systems was developed. The system utilized the data collected by GPS and a PC-based vision system in a GIS environment. GIS Arcview software was used for the purpose of data display, query, manipulation and analysis.The developed system provided a safer pavement condition data collection technique, flexible data storage, archiving, updating and maintenance priorities updating. Maintenance priorities were assigned based on priority indices values computed by priority index (PI) or available budget criterion. This technique was cost-effective and offered wise-based decision making for different maintenance activities and programs.Using average daily traffic (ADT), distance from maintenance unit (R), pavement section area and pavement age, statistical models were developed to forecast pavement distress quantities. It was found that ADT and pavement age variables were the most significant factors in the distresses quantification.     

基于图象子块分布特性的路面破损图象特征提取

由于路面破损形式的多种多样,造成路面破损分类[1]成为一大难题,这极大的限制了路面破损自动检测的普及和发展,使得路面破损自动检测即使在发达国家也普及得不够理想。本文在前文提出的破损密度因子的基础上,进一步设计了出方向密度因子,得到一种基于图象子块分布特性的路面破损识别算法。通过仿真,验证了其对常见的5种路面破损类型进行分类的可行性。为了进一步验证我们提出的识别算法,论文选择了另外一种路面破损分类算法,即PROXIMITY算法进行神经网络仿真对比。神经网络的训练样本是两组,测试样本也是两组,进行了四次仿真对比。四次仿真结果都显示方向密度因子算法优于PROXIMITY算法。     

Testing development of different surface treatments on pervious concrete

Pervious concrete systems are developing stormwater management technologies which also have wintertime benefits as melting snow may percolate into the system instead of refreezing on the surface. Enhancing the surface microtexture of pervious concrete may also be beneficial in preventing icing or slipping by pedestrians. This research explored different surface treatments on pervious concrete specimens both qualitatively from personal judgements, and quantitatively through static friction measurements with a spring balance with respect to “slipperiness”. The tests were performed on both dry and wet specimens. One aim was to determine whether the spring balance method may be a simple test for comparing surface treatments on pavement samples with little surface area such as laboratory specimens or sidewalk sections. The other purpose was to make a preliminary decision of which surface treatments to use for a sidewalk installation for future studies on wintertime performance. The reliability analysis of the spring balance results showed that there was high operator consistency. In addition, there was a high level of consistency on average results between the quantitative and qualitative methods. This implies that the spring balance test may be an acceptable methodology for comparative analyses with respect to static friction.     

南京市道路交叉口路面病害调查及原因分析

根据南京市道路交叉口路面破坏状况调查、承载能力评定以及路面材料的性能检测结果 ,分析了道路交叉口路面病害的主要原因 ,并提出了防治对策     

A test of porous pavement effectiveness on clay soils during natural storm events

Porous pavements allow precipitation to infiltrate through the pavement to the soil, reducing the volume of stormwater runoff produced at a site. However, porous pavements are not widely used on fine-grained soils due to concerns about their performance. Our objective was to investigate the efficacy of porous pavements in controlling stormwater runoff on clay soils. We compared the performance of an asphalt parking lot and a porous pavement parking lot of grass pavers in Athens, Georgia, USA, over relatively small and low-intensity rain events. The porous lot produced 93% less runoff than the asphalt lot. The total volume of runoff at the porous lot was significantly less than the asphalt lot (t = 2.96, p = 0.009). Turbidity was significantly greater at the asphalt lot (t = 6.18, p < 0.001) whereas conductivity was significantly higher at the porous lot (t = 2.31, p = 0.03). Metal and nutrient concentrations were below detection limits at both lots during seven of nine small storm events. During events in which we could detect pollutants, calcium, zinc, silica, and total phosphorus concentrations were higher at the asphalt lot whereas total nitrogen concentrations were greater at the porous lot. Our results suggest porous pavements are a viable option for reducing stormwater runoff and some pollutants from small storms or the first flush from large storms on clay soils.     

Pavement sustainability index for highway infrastructures: A case study of Maryland

Pavement deterioration creates conditions that undermine their performances, which gives rise to the need for maintenance and rehabilitation. This paper develops a mathematical multi-linear regression analysis (MLRA) model to determine a pavement sustainability index (PSTI) as dependent variable for flexible pavements in Maryland. Four categories of pavement performance evaluation indicators are subdivided into seven pavement condition indices and analyzed as independent variables for each section of pavement. Data are collected from five different roadways using field evaluations and existing database. Results indicate that coefficient of determination (R²) is correlated and significant, R² = 0.959. Of the seven independent variables, present serviceability index (PSI) is the most significant with a coefficient value of 0.032, present serviceability rating (PSR) coefficient value= 0.028, and international roughness index (IRI) coefficient value= ?0.001. Increasing each unit value of coefficients for PSI and PSR would increase the value of PSTI; thereby providing a more sustainable pavement infrastructure; which explains the significance of the model and why IRI will most likely impact environmental, economic and social values.     

IN-SITU HYDRAULIC PERFORMANCE OF A PERMEABLE PAVEMENT SUSTAINABLE URBAN DRAINAGE SYSTEM

There is growing awareness that sustainable urban drainage systems can offer a more sustainable option for the management of stormwater runoff than conventional drainage systems. This paper presents in-situ performance data from a permeable pavement system which was installed to collect and treat stormwater runoff from a motorway servicestation car park. Data on rainfall at the site and outflow from the permeable pavement were collected over a thirteen-month period, and twenty rain events were studied in detail. The system provided a large degree of attenuation in terms of (a) reduction in peak flows, and (b) extended duration of outflows compared with rain events. Infiltration tests provided information on the processes of water entry into the pavement system and impacts of clogging on hydraulic performance.     

Development of performance assessment tools for a highway bridge resulting from controlled progressive monitoring

As highway bridges continue to deteriorate given the increased service life, increase in vehicle demand and exposure to harsh environmental climates, new methods of monitoring their in situ performance are of high priority. Damage within the structure can alter various load demand and capacity characteristics, affecting the overall integrity of the bridge. Discussed in this paper is the monitoring of a simple span bridge superstructure under various induced damage states. Strain measurements were recorded at the midspan and north abutment of each girder. Six levels of damage progression were implemented at a rocker bearing and various diaphragms to girder connections. Transverse load distribution factors (DFs) and neutral axis (NA) locations were measured for each damage case and evaluated against the baseline undamaged response. These measurements serve to provide a possible method of damage detection using load-testing parameters already employed by various transportation agencies. Next, a performance index (PI) is developed for this stringer/multi-girder bridge utilising the NA and DF response from the steel girder system and the allowable stress design load-rating data. The ratio of NA to DF was compared to the inventory load rating for each girder at each damaged state. The data were fitted with a power regression model to form the PI. Furthermore, a 95% prediction interval was used around the predicted response to capture all the data from the testing. The model was applied to the damaged structure as well as two additional stringer/multi-girder bridges. The objective of the PI is to complement existing qualitative assessment protocols with quantitative results for improving the condition assessment process.     

Optimum mix design of enhanced permeable concrete – An experimental investigation

Permeable pavement, due to its high porosity and permeability, is considered as an alternative to traditional impervious hard pavements for controlling stormwater in an economical and friendly environmental way. Permeable concrete normally made of single-sized aggregate bound together by Portland cement, using restrictedly as a pavement material, because of its insufficient structural strength. Aimed at developing a new type of permeable concrete with enhanced structural strength, various mix designs were attempted and their effects on the compressive strength and permeability of permeable concrete were investigated in this research. The optimum aggregate and mix components design were consequently recommended for enhanced permeable concrete.     

Asphaltic concrete overlays on surface-treated pavements with lateritic gravel bases

The design and performance of asphaltic concrete overlays for surface-treated pavements with lateritic gravel bases and subbases using the results of Benkelman beam deflection measurements are discussed. It is found that failure to consider pavement distress factors, local materials and environmental conditions in design are inadequate and early signs of distress are exhibited. It is concluded that the high percentage of unpredictable generated traffic is an important contributing factor to performance. An assessment of stress interaction between the existing surface-treated pavement with granular bases and subbases and the asphaltic concrete overlay needs to be considered in the design process. An appropriate approach would be to consider the overlay design as a new asphaltic concrete-surfaced pavement with granular base and subbase.     

基于沥青路面功能性能的预防性养护时机指标

路面预防性养护是国内外近年来研究的热点,路面预防性养护对维持良好的路面性能具有重要的意义。预防性养护的成功与否及其效益与进行预防性养护的时机密切相关,然而对于预防性养护的时机目前国内外还没有很好的解决办法。文章从预防性养护的作用出发,结合我国公路事业发展的现状,提出了基于沥青路面功能性能的预防性养护指标体系:路面沥青老化指标、路面渗水系数、路面行车安全性指标、平整度和路面状况指数(PCI) ,以及获取这些指标需要进一步解决的关键问题。     

Status of porous pavement research

This paper discusses the U.S. Environmental Protection Agency's porous pavement research program along with the economics, advantages, potential applications, and status and future research needs of porous pavements.Porous pavements are an available stormwater management technique which can be used on parking lots and low volume roadways to reduce both stormwater runoff volume and pollution. In addition, groundwater recharge is enhanced. Also, cost reductions result due to elimination of curbs, drains, and small sized storm sewers.Porous asphalt pavements consist of a relatively thin course of open graded asphalt mix over a deep base of large size crushed stones. Water can be stored in the crushed stone base until it can percolate into the subbase or drain laterally. Other porous pavement types include concrete lattice blocks and a porous concrete mix.     

Evaluation of geosynthetic reinforcement in unpaved road using moving wheel load test

The common cause of failure of the unpaved road is associated with undesirable ruts and deformations. Use of geosynthetic reinforcement is a solution to this pavement distress problem as experienced in limited research works, especially in the laboratory studies. This study presents the performance of geosynthetic-reinforced unpaved roads subjected to moving wheel load tests to investigate the effect of geosynthetic reinforcement on the pavement surface deformation of the unpaved roads. Unreinforced and geosynthetic-reinforced unpaved road test sections consisting of varied reinforcements were constructed in a test pit, 9 m long and 2.7 m wide. Geogrid and geotextile were used for reinforcing the unpaved road test sections. The rut depth was measured in the transverse direction of the wheel path after certain number of wheel passes. Traffic Benefit Ratio (TBR) and Performance Index (PI) were employed in the study for the evaluation of the effectiveness of geosynthetic reinforcement in unpaved roads. After 350 vehicle passes, the geotextile-reinforced and geogrid-reinforced test sections get rutting reduced by 44.89% and 28.57%, respectively. The test results indicate that inclusion of geosynthetic reinforcement significantly improves the rutting resistance and stability of reinforced test sections compared to the unreinforced test sections.     

Stormwater quality performance of a macro-pervious pavement car park installation equipped with channel drain based oil and silt retention devices

This paper reports the results of a two year field monitoring exercise intended to investigate the pollution abatement capabilities of a novel system which offers an alternative to the, now well established, pervious pavement system as a source control device for stormwater management. The aim of this study was to determine the effectiveness of a live installation of a macro-pervious pavement system (MPPS) (operated as a visitors' car park at a prison in Central Scotland) in retaining and treating a range of pollutants which originate from automobile use or become concentrated on the parking surface from the wider environment. The MPPS is a sub-class of pervious pavement system where the vast majority of the surface is impermeable. It directs stormwater into a pervious sub surface storage/attenuation zone through a series of distinct infiltration points fast enough to prevent flooding during the design storm. In the particular system studied here the infiltration points consist of a network of oil/silt separation devices with extensive further pollutant retention/degradation provided during the passage of stormwater through the sub surface zone. Approximately 12 months after the car park was completed a sampling regime was instigated in which grab samples were collected at intervals from each of the three sub catchments whilst, simultaneously, samples were collected directly from the, pollutant retaining, infiltration devices. Through investigation of samples collected at the upstream end of the system, the retention of significant amounts of hydrocarbons and heavy metals in the initial collection devices has been illustrated and the analysis of effluent samples collected at the outlet points indicate that the system is capable of producing effluent which is of a standard comparable to that expected from a traditional pervious pavement system and is acceptable for direct release into a surface water receptor. The system offers the opportunity to accrue the benefits of a pervious pavement when the use of traditional paving surfaces is the preferred option.     

低影响开发与绿色建筑的雨水控制利用

基于我国绿色建筑评价体系中的雨水控制利用相关内容及现状,论述了低影响开发的理念和关键技术,探讨了在绿色建筑体系应用低影响开发技术的可行性和必要性。举例分析了低影响开发雨水控制利用技术措施在绿色建筑体系中的具体实施方案,以及实施低影响开发理念带来的环境、经济和社会效益。提出在绿色建筑中应将雨水控制利用综合性技术和建筑、景观规划设计及基础设施建设统筹考虑,有机结合。期望为绿色建筑体系中生态环境保护,科学、合理的雨水控制利用提供参考。     

透水砖和下凹式绿地对城市雨洪的影响

为考察不同雨洪措施对防洪和增加雨洪资源利用量的贡献,采用城市暴雨雨水管理模型(SWMM),对北京某区域内铺设透水砖和采用下凹式绿地措施的排水管道主要断面洪峰流量的变化进行了计算分析。结果表明,铺设透水砖和采用下凹式绿地均可有效削减洪峰流量,减小径流系数,从而增加雨洪资源的利用量。但对于不同降雨频率的地区,下凹式绿地在降雨频率较大的地区,雨洪利用效果较好;透水砖则在降雨频率较小的地区,雨洪利用效果较好。该研究成果可以用来评价不同雨洪措施在不同降雨频率下对城市雨洪的利用效果,为防洪排涝工程提供了一定的技术支持。     

Application of Markov chains and Monte Carlo simulations for developing pavement performance models for urban network management

Existing performance models developed for interurban pavements are not applicable to urban pavements due to differences in traffic demands and deterioration trends. The objective of the study was to develop performance models for the management of urban pavement networks. Markov chains and Monte Carlo simulation were applied to account for the probabilistic nature of pavements deterioration over time, using data collected in the field. One of the advantages of this methodology is that it can be used by local agencies with scarce technical resources and historical data. Eight performance models were developed and successfully validated for asphalt and concrete pavements in humid, dry and Mediterranean climates with different functional hierarchies. The resulting models evidence the impact of design, traffic demand, climate and construction standards on urban pavements performance. Predicted service life of asphalt and concrete pavements in primary networks are consistent with design standards. However, pavements in secondary and local networks present shorter and longer service life compared to design life, respectively. Climate is a relevant factor for asphalt pavements, where higher deterioration was observed compared to that expected. Opposite to this, no relevant differences between design and performance can be attributed to climate in concrete pavements.     

活性掺合料对路面水泥混凝土性能的影响和应用研究

针对粉煤灰和硅粉等活性掺合料对路面水泥混凝土性能的影响进行了研究.采用正交法设计了十种混凝土配合比,对在标准条件下养护28天的各配比混凝土试件进行了抗折强度、抗压强度、抗渗透性能和抗冻融性能的测试,并通过回归方法建立了各指标与配合比的关系.试验结果表明,通过添加适量的粉煤灰和硅粉,可以在不降低混凝土强度的基础上有效地提高混凝土的密实性和抗渗性能,并改善其抗冻融性能.同时,再通过技术、经济比较及现场验证,得出适合当地实际情况的最佳配合比.