Skid Resistance Measurements Research Articles

Improved British pendulum test using curved slider

ABSTRACT The conventional British pendulum tester (BPT) utilises a cuboid rubber slider and measures the skid resistance between its front slider edge and a test surface. This standard test method is known to produce erroneous skid resistance measurements on grooved pavements, owing to impacts between the straight slider edge of BPT and the vertical walls of pavement grooves. To overcome the problem, this study replaced the cuboid slider with a curved slider having an external radius of 100 mm, constructed of the same rubber material as the standard BPT rubber slider. The ability of the proposed improved device to eliminate the vertical-wall impact problem and provide correct skid resistance measurements of a grooved surface was verified experimentally and numerically. A full-scale prototype was fabricated for this purpose. Experimental validation tests involving the standard cuboid-slider BPT and the curved-slider BPT were conducted, and the test results were analysed with the aid of finite-element numerical models. The results confirmed that the proposed curved-slider BPT can provide more consistent and accurate skid resistance measurements compared to the standard BPT, for both grooved and ungrooved pavements.

ХАРАКТЕРИСТИКИ ПОВЕРХНІ ПОКРИТТЯ ДОРОЖНЬОГО ОДЯГУ СТАНДАРТНІ МЕТОДИ ВИМІРЮВАННЯ

Abstract. The texture of a road pavement surface and its skid resistance which concerns its ability to resist the vehicle wheel skidding have been accepted worldwide as the road safety criterion. These characteristics are interconnected in that the texture affects the skid resistance. The goal of the paper is to carry out the comparative analysis of valid road safety and performance parameters and its dependence on the road pavement surface texture and the comparative analysis of international and regional standard methods of road surface texture and skid resistance measurements covering methods acceptable for the road network survey. The main principles of the road pavement surface texture categorization were analyzed with its ranging as micro-, macro- and megatexture where the microtexture parameters sufficiently influence adhesion between pavement and tire especially in wet conditions. It was stated also that the macro- and megatexture parameters govern the rolling resistance and dynamic effect where the last is attributable to the comparable dimensions of the megatexture wavelength and the tire footprint and also affects the increase in loading that may be equal to the additive ESALs up to 40 %. The high-range wavelength roughness exceeding λ = 500 mm should be viewed as the road surface unevenness, as the feature negatively governing the vehicle road-holding ability. Also the contemporary high-performance techniques and methods for the road pavement surface skid resistance determination were reviewed and it was shown that these method and the according equipment should be divided as performing the longitudinal friction measurements or the side-way force measurements to be carried out under conditions that allow the investigators to distinguish the contribution made by the road pavement surface characteristics to the friction force. The possibilities of the usage of the results of the mathematical analysis of the road surface profile survey were analyzed separately and it was shown that the power spectral density can be accepted as a valid parameter for non-direct estimation of the road surface texture through international roughness index IRI. Keywords: road pavement, surface texture, profilometer, skid resistance, slid angle, friction coefficient, international roughness index.

A review on the impacts of connected vehicles on pavement management systems

ABSTRACT The advent of connected vehicles (CVs) starts a new era in the field of pavement evaluation. With CVs on roads, the wide fleet of vehicles will constantly transmit pavement data to central servers and also share the necessary information with one another. Such a system presents opportunities for continuous, crowdsourced, and cost-effective monitoring of pavement assets and the development of pavement management databanks. This study reviewed the published studies on CV-based pavement evaluation, summarised the findings, and identified research gaps. In the published resources, 9 different applications have been proposed for CVs in the field of pavement monitoring (some applications are discussed in more than 1 resource): roughness measurement (proposed in 37.5% of resources), distress detection (31%), gathering road weather data (22%), slippery pavement recognition (19%), distress classification (12.5%), road geometry/type evaluation (9%), road amenities detection (9%), skid resistance measurement (6%), and distress intensity measurement (4.5%). The performed case studies were also scrutinised based on utilised sensors, data types, analysis methods, and connectivity messages and networks. In the end nine research subjects with no attention in the previous studies and five research subjects with insufficient attention in the published articles were identified.

A state-of-the-art review of measurement and modelling of skid resistance: The perspective of developing nation

A critical review of lab and field measurement methodologies, harmonization in measuring techniques, and modelling of skid resistance of asphalt concrete pavement have been provided. Although several past studies have provided literature review on general topics of skid resistance, to the best of the author’s knowledge, none of them have compressively covered the topic considering the status & requirements of developing nations. There has been significant development in speed with the improvement in computational facilities. In modern times, with the improvement in infrastructure quality in developing nations, permitted speeds have also drastically increased. To avoid skid-related accidents, it is important to develop good practices in maintaining sufficient skid resistance. The requirements and the availability of technology might be significantly different in developing nations. The suitability and limitations of various methods used for capturing the skid characteristics of the surface have been outlined. The harmonization in skid resistance measurement using laboratory and field-testing methods has been summarized. Correlation analysis of various in-situ and laboratory test data has been made to maintain a better harmony of measurement either in the field or in the laboratory. In the subsequent sections, progress in the modelling approach (analytical to numerical) has been discussed in brief. Computational capabilities of an analytical and numerical modelling approach for predicting pavement skid resistance characteristics have been reviewed. These models have been developed to consider complex attributes of tire pavement interactions like hydroplaning, temperature rise in the tire, mix morphology, tire inflation, and vehicle acceleration and deceleration for predicting skid resistance. These attributes of skid resistance have been discussed in detail and presented a basic overview of the model development process which is missing in past review studies. Few recent studies on skid resistance measurement and modelling to highlight the use of new technology and improvements over conventional techniques have been presented in the manuscript which has not been reviewed earlier. Critical factors affecting the skid resistance model like hydroplaning, tire-related parameters, temperature, and surface texture have been highlighted in this manuscript. Few key research directions have been suggested as the scope of future study to predict a more reliable skid resistance model.

Experimental-cum-numerical approach for directional skid resistance measurement of grooved pavements

Currently there is no standard procedure for measuring the directional skid resistance of grooved pavements using the British pendulum tester (BPT). This study shows that BPT measured directional British pendulum numbers (BPNs) could over-estimate the actual directional BPN values of grooved pavements by more than 10 BPN at test angle of 90° to the grooves. The present study develops an experimental-cum-numerical procedure to provide corrections to measured directional BPNs of grooved pavements. Based on a single directional BPN measured in any test direction, the procedure permits one to calculate the full range of corrected directional BPNs at test angles between 0 and 90°. Corrected BPNs are derived from rubber-pavement friction coefficients back-calculated from measured BPNs. This was achieved through the application of two numerical skid resistance simulation models: a finite-element BPT simulation model and a finite-element sliding tire simulation model. The validity of the proposed approach was verified experimentally.

Effective pavement skid resistance measurement using multi‐scale textures and deep fusion network

AbstractPavement skid resistance measurement is a fundamental component of roadway management and maintenance. Most traditional approaches rely on manual operations or heavy devices, which lead to a labor‐intensive, inefficient, and vulnerable testing environment. Precise laser scanning technology lays a solid foundation for effective and continuous pavement friction measurement. This paper proposed an automated pavement friction estimation model using 3D point cloud data and a deep neural network. The fine‐grained texture data of over 800 pavement sections with various anti‐skidding abilities were collected. The impact of the multi‐scale textures on pavement friction was separated and analyzed via two‐dimensional wavelet decomposition. A multi‐input fusion network with deep aggregation modules was designed to fuse the features of sub‐images generated by wavelet decomposition. The results show that the average prediction error is 0.0935, outperforming most state‐of‐the‐art models. The impact of different texture scales on friction estimation is then revealed. The proposed method provides a new tool for effective and large‐scale pavement friction evaluation.

Evaluation of Various Surface Cleaning Techniques Inside Tunnels on Pavement Skid Resistance.

A request started a comprehensive investigation on the Skid Resistance (SR) inside a highway tunnel in Madrid, Spain, to determine methods that will improve or maintain the SR above the minimum required level (60), after the application of Hydroblasting, without the need of pavement surface rehabilitation. The right lane located on eight sections inside tunnel XC was used as a test section, in which three went thru the application of water pressure applied weekly, biweekly, and monthly. Three other sections for surface sweeping at the same frequencies and two untreated sections as control. Using the Microgriptester, weekly SR measurements taken before and after tracked the pavement response. Results showed that SR decreased weekly depending on the frequency of the treatment applied and for higher frequencies, SR was almost at the same level. Water pressure and sweeping applied weekly, biweekly, and monthly, during the two months testing period, maintained the SR level above the required value of 60 and the untreated sections showed that pavement surface must be treated to maintain the SR above 60.

Progress and Monitoring Opportunities of Skid Resistance in Road Transport: A Critical Review and Road Sensors

Skid resistance is a significant feature that provides consistent traffic safety management for road pavements. An appropriate level of Skid resistance describes the contribution that the pavement surface makes to tire/road friction, and the surface of the road pavement can reduce vehicle operation cost, traffic accidents, and fatalities, particularly in wet conditions. Wet conditions decrease the level of the skid resistance (pavement friction), and this may lead to serious struggles related to driving on the road pavement (e.g., skidding or hydroplaning), which contributes to higher crash rates. The knowledge of skid resistance is essential to ensure reliable traffic management in transportation systems. Thus, a suitable methodology of skid resistance measurement and the understanding of the characterization of the road pavement are key to allow safe driving conditions. This paper presents a critical review on the current state of the art of the research conducted on skid resistance measurement techniques, taking into account field-based and laboratory-based methodologies, and novel road sensors with regard to various practices of skid resistance, factors influencing the skid resistance, the concept of the minimum skid resistance and thresholds. In conclusion, new trends that are relevant to data collection approaches and innovative procedures to further describe the data treatment are discussed to achieve better understanding, more accurate data interoperability, and proper measurement of skid resistance.

Improved non-contact 3D field and processing techniques to achieve macrotexture characterisation of pavements

Macrotexture is required on pavements to provide skid resistance for vehicle safety in wet conditions. Increasingly, correlations between macrotexture measurements captured using non-contact techniques and tyre-pavement contact friction are being investigated in order to enable more robust and widescale measurement and monitoring of skid resistance. There is a notable scarcity of research into the respective accuracy of the non-contact measurement techniques at these scales. This paper compares three techniques: a laser profile scanner, Structure from Motion photogrammetry and Terrestrial Laser Scanning (TLS). We use spectral analysis, areal surface texture parameters and 2D cross-correlation analysis to evaluate the suitability of each approach for characterising and monitoring pavement macrotexture. The results show that SfM can produce successful measures of the areal root mean square height (Sq), which represents pavement texture depth and is positively correlated with skid resistance. Significant noise in the TLS data prevented agreement with the laser profiler but we show that new filtering procedures result in significantly improved values for the peak density (Spd) and the arithmetic peak mean curvature (Spc), which together define the shape and distribution of pavement aggregates forming macrotexture. However, filtering the TLS data results in a trade-off with vertical accuracy, thus altering the reliability of Sq. Finally, we show the functional areal parameters Spd and Spc are sensitive to sample size. This means that pavement specimen size of 150 mm × 150 mm or smaller, when used in laboratory or field observations, are inadequate to capture the true value of areal surface texture parameters. The deployment of wider scale approaches such as SfM and spectrally filtered TLS are required in order to successfully capture the functional areal parameters (Spc and Spd) for road surfaces.

The concept of pavement skid resistance state

The Concept of Skid Resistance State for highway pavements is introduced in this paper. The Concept states that at a given point in time, each unit length of a pavement has a fixed deterministic skid resistance value under a given set of pavement, environmental and vehicle operating conditions. A set of the operating conditions is defined by the following parameters: Vehicle tyre geometric and structural properties, wheel load, tyre pressure, vehicle speed, tyre slip ratio, tyre slip angle, pavement microtexture and macrotexture properties, ambient temperature, and pavement surface water film thickness. It is demonstrated in this study that, according to the proposed Concept, the skid resistance characteristics of a pavement can be fully described by a computer simulation model that analyses tyre–pavement–fluid interaction based on solid mechanics and fluid dynamics theories. Once the computer skid resistance model of a pavement section has been established, its skid resistance value under any vehicle–pavement–environmental operating condition can be calculated. Currently, there are already a number of computer skid resistance models developed by pavement researchers. Using one of these models for illustration, this paper explains how the Concept of Skid Resistance State is applied. The rationale, calibration process of the model, and input parameters are described; followed by a numerical demonstration of the establishment of the Skid Resistance State of an example pavement section. The significance and potential applications of the Concept on functional pavement mix design, pavement friction maintenance management, and harmonising of skid resistance measurements by different devices are also described.

Evaluation of airfield pavement micro and macrotexture in the light of skid resistance (friction coefficient) measurements

Appropriate skid resistance properties of airfield pavements are extremely important in terms of the safety of air operations. When discussing skid resistance properties of airfield pavements, we should not limit the subject only to the friction coefficient, which determines the state of its roughness. Attention should be paid to the fact that a significant component of friction characteristics of a tyre/pavement contact surface is the pavement texture (microtexture and macrotexture). The authors of the article presented the currently applied study methods in the scope of evaluating the texture of road and airfield pavements. The paper also presents sample results of field tests, which were conducted on new airfield pavements (executed in the cement concrete and asphalt concrete technology), as well as their short analysis in relation to evaluating the skid resistance properties (friction coefficient). Particular attention was paid to the current requirements in this scope, imposed on airfield pavements and the assessment criteria of the obtained results. Moreover, the paper also presents a direction of further works conducted by the authors with a broader team, in the scope of developing the study method for the assessment of airfield pavement texture.

Briefing: Measuring pavement skid resistance – comparing manually pushed and trailer-mounted devices

In 2009, a manually pushed device was developed to measure the dry and wet skid resistance of pavement surfaces at walking pace. The device is based on the same principle as a larger trailer-mounted version and provides a continuous measurement of skid resistance; it is particularly suitable on sites where the survey speed cannot be achieved by trailer- or vehicle-mounted devices. The manually pushed device is also useful for restricted test sections and where the incline, camber or gradient are not desirable for other survey methods. However, the device is not currently covered by a national or international test standard. Its use has also been restricted due to a lack of published research regarding the correlation of results with other methods of measurement. This paper describes on-site testing conducted using the manually pushed device to assess the correlation of the test results with results provided by a trailer-mounted device. The repeatability of the test method and the influence of survey speed on the test results are also examined.

Skid Resistance Characteristics of Asphalt Pavements in Hot Climates

AbstractThis research assesses the influence of temperature variation on GripTester (Findlay Irvine, Penicuik, Scotland) skid resistance measurements of asphalt pavements in Qatar. It evaluated a t...

Assessment of traffic noise due to transverse rumble strips at residential areas

Transverse rumble strips (TRS) are commonly being installed to alert the drivers through sound and vibration effects. The sound produced affects the existing traffic noise level which caused noise annoyance to the nearby residents. This study aims to assess the traffic noise due to TRS at residential areas by determining the roadside noise levels, traffic and road characteristics and evaluating the relationship between these parameters. Middle overlapped (MO), middle layer overlapped (MLO) and raised rumbler (RR) TRS profiles with same thickness were selected. The measurements of roadside noise levels and skid resistance were conducted using sound level meter (SLM) and British pendulum tester (BPT) respectively. Traffic characteristics were evaluated using previous data measured using automatic traffic counter (ATC). In overall, MLO produced highest roadside noise levels with increase of 20.5dBA from baseline. Generally, the increase of roadside noise level due to TRS is strong with speed, weak to medium with skid resistance of TRS and no relationship with traffic volume. Based on three TRS profile types, MLO is not suitable to be installed on the roadways adjacent to the residential areas as the increase of roadside noise level is significant which is more than 5dBA compared to MO and RR.

Investigating the effect of temperature variations on the measured airfield pavement skid resistance

Airfield temperatures can range between −30 °C and +50 °C. Therefore, it is critical to correct the measured skid resistance values for field temperatures. To achieve this, several asphalt slabs were prepared and tested using the British Pendulum Tester. A special fluid was used to conduct skid resistance tests at below freezing temperatures. Test results were used to develop correction models for skid resistance under temperature variations, to be used by airfield operators. The results of this research are unique and important where it is the first time to include below freezing temperatures in skid resistance measurements and correction models.

Using a constructive pavement texture index for skid resistance screening

Skid resistance measurement is one of the major measurements used to assess road safety. Typical devices used for measuring skid resistance include single point checking type and continuous measurements type. However, conducting periodic full roadway network skid resistance survey can be a relatively time consuming and difficult task because of the limited water carrying capacity used by all kinds of devices, including the continuous types. On the contrary, measurement of pavement surface texture can be conducted easily and continuously by most profilers. This research investigates the relation between pavement skid resistance and surface texture. The focus is on the development of a texture index that can serve as a screening indicator to filter out the high-risk pavement sections for further skid resistance measurement. Two measuring devices, GripTester (GT) and National Taiwan University laser profiler (NTU Profiler), were used to collect data on pavement skid resistance and texture in a network of 555 sections, respectively. The pavement texture index of the mean difference of elevation (MDE) is calculated at a 1mm profile interval, which is a very promising indicator to represent pavement skid resistance. Through a sensitivity study, the MDE threshold of 0.15mm is observed to provide a relatively reasonable screening function that filters out 29.01% of the entire surveyed network for further skid resistance inspection. It averted more than 70% skid resistance measurement capacity of the entire network. The accuracy of correct judgment by the selected threshold is about 80%, only 3.78% of roadway sections considered for further inspection of the recommended list are not included.

Gait of dairy cows on floors with different slipperiness.

This study assessed the slip resistance of different types of solid flooring in cattle housing using a range of technical tests and gait analysis. Dynamic and static coefficient of friction, skid resistance, and abrasiveness were tested on concrete flooring with a smooth finish, a grooved pattern, or a tamped pattern, acid-resistant mastic asphalt, soft rubber mats, and a worn slatted concrete floor. Coefficients of friction and skid resistance were tested under clean and slurry-soiled conditions. Linear kinematic variables were assessed in 40 cows with trackway measurements after the cows passed over the floors in a straight walk. All gait variables were assessed as deviations from those obtained on the slatted concrete floor, which was used as a baseline. The coefficient of friction tests divided the floors into 3 categories: concrete flooring, which had a low coefficient of friction (0.29-0.41); mastic asphalt flooring, which had medium values (0.38-0.45); and rubber mats, which had high values (0.49-0.57). The highest abrasion (g/10 m) was on the asphalt flooring (4.48), and the concrete flooring with a tamped pattern had significantly higher abrasiveness (2.77) than the other concrete floors (1.26-1.60). Lowest values on the skid-resistance tests (dry/wet) were for smooth concrete (79/35) and mastic asphalt (65/47), especially with a slurry layer on the surface. Gait analysis mainly differentiated floors with higher friction and abrasion by longer strides and better tracking. Step asymmetry was lower on floors with high skid-resistance values. The most secure cow gait, in almost every aspect, was observed on soft rubber mats. Relationships between gait variables and physical floor characteristics ranged from average to weak (partial correlations 0.54-0.16). Thus, none of the physical characteristics alone was informative enough to characterize slip resistance. With reference to gait analysis, the abrasiveness of the hard surfaces was more informative than the coefficient of friction, but the effect of pattern was better detected by skid-resistance measurements. Consequently, several physical characteristics are needed to objectively describe the slip resistance of cattle floors. Soft rubber mats gave better tracking than hard, solid floors, even with a grooved surface or a tamped pattern.

A laboratory procedure for predicting skid and polishing resistance of road surfaces

Skid resistance of road surfaces is an important safety parameter. Decreasing skid resistance correlates with increasing number of accidents. The presented study aims for a correlation between lab-based polishing simulation and skid resistance measurement and evolution of the skid resistance under traffic in the field. A prediction model for skid and polishing resistance based on the Wehner/Schulze device was developed. The lab procedure as a basis for the model works on the hypothesis that a maximum level of skid resistance exists that can be regenerated even from a highly polished state by sandblasting of the surface. This hypothesis was verified for an asphalt and concrete surface material. The prediction model was set up by correlating field data on skid resistance and traffic volume from 14 test sections to cores taken from these test sections and tested in the lab. A linear regression links the cumulated traffic volume in the field with the number of polishing passes in the Wehner/Schulze device. Thus, it is possible to simulate millions of wheel passes within a couple of hours in the lab to generate equal skid resistance level and predict the skid resistance level of a road surface after years under traffic.

Comparative Analysis of Skid Resistance for Different Roadway Surface Treatments

Pavement skid resistance impacts road functionality and can affect user safety and vehicle operation costs. This study was an investigation of the effect of sealcoats on skid resistance. Seven different sealcoats-fog seal, chip seal, slurry seal, sand seal, high-friction seal, cape seal, and glass seal-were lab and field tested. Laboratory samples were further tested in the field on pavement sections. To validate lab and field tests, high-friction seal was tested on recently placed pavement sections in Anchorage, Alaska. The British Pendulum tester was used to measure sealcoat skid resistance. A minimum of 40 randomized readings from the lab and field were sorted. Statistical analysis of lab and field data showed insignificant differences between all sealcoat types with the exception of cape seal. The mean skid resistance of sealcoats indicated a preference for high-friction and glass seals. On average, high-friction and glass seals had skid numbers close to 40, providing effective skid resistance as well as safer riding quality. The field and lab data of high-friction sealcoat were validated on recently paved roads in Anchorage. The results highlighted the consistency of skid resistance measurements for the three types of testing conditions (lab, field, and real roadway) for high-friction sealcoat.

Incorporating Braking Distance Evaluation into Pavement Management System for Safe Road Operation

Maintaining a sufficiently short stopping distance is an important requirement for safe road operation. Stopping sight distances of road sections are decided during the highway alignment and roadway geometric design phase of the road development process. A pavement friction coefficient is used in the calculation of the stopping distances. Since pavement friction coefficient deteriorates with time under traffic action, and the available friction also reduces in wet weather, it is important for pavement maintenance engineers to ensure that sufficient skid resistance is maintained under actual operating conditions so that the stopping distances of road sections are less than the required safe stopping distance. This result requires pavement engineers to monitor regularly the available pavement skid resistance and the corresponding stopping distance of individual road sections. Because skid resistance is an accepted pavement condition to be measured in a pavement management system, it is proposed in this study that braking distance assessment be included as a part of the pavement condition monitoring program of a pavement management system. The proposed procedure consists of two parts: ( a) measurement of skid resistance and evaluation of braking distance and stopping distance and ( b) monitoring of the deterioration trends of individual road sections. The detailed procedure and the analytical tools necessary for the evaluation and prediction of braking and stopping distances, including a finite element skid resistance simulation model, are presented. A numerical example is presented to illustrate the concept and working of the proposed procedure.