Skid Resistance Measurements Research Articles

Multi-scale study of the polishing behaviour of quartz and feldspar on road surfacing aggregate

ABSTRACTIn this paper, the exact mechanisms as to how petrographic properties of aggregate influence the polishing behaviour quantitatively were identified. Since the aggregate is composed of the different rock-forming minerals, the analyses conducted in this research project focused not only on the aggregate but also on crystals/minerals. The hardest and most abundant rock-forming minerals found on earth – quartz and feldspar – were investigated with polishing tests with the Aachen Polishing Machine on granite aggregates from four sources which exhibit different mineralogical properties. Changes of the aggregate texture and minerals were studied based on texture measurements and skid resistance measurements obtained by means of the Pendulum Test and the Wehner/Schulze device. The influences of mineral composition and crystal size on the changes of the micro-texture and skid resistance of the aggregates were determined by comparing the four granites. The polishing and wearing behaviour of quartz and various feldspars (albite, microcline and plagioclase) were characterised quantitatively by means of a spectral analysis and abrasion analysis. The results show that the micro-texture of exposed minerals is greatly smoothened on wavelengths from 100 to 500 μm. Fine-grained quartz or feldspar crystals tend to be rougher than medium of large-sized crystals. Quartz exhibits more favourable properties than feldspar between 100 and 500 μm; this is especially true for fine quartz crystals. The correlation that more content of coarse-grained quartz leads to high friction value cannot be proved in this research.

Status of the EU-project ROSANNE

ROSANNE is a collaborative project in the Seventh EU Framework Programme which aims at developing/harmonising measurement methods for skid resistance, noise emission and rolling resistance of road pavements as a preparation for standardization. To achieve this, the project is following the recommendations of key predecessor projects like TYROSAFE, HERMES, SILVIA, SILENCE and MIRIAM as well as considering the ongoing work in CEN and ISO groups. Work package 1 deals with skid resistance and aims at the harmonization of skid resistance measurement following the TYROSAFE Roadmap, by deriving conversion factors for friction indices based on similar groups of devices, namely longitudinal and sideways skid resistance measurement devices. During the first project year a first round robin test was carried out in Nantes, ten different devices participated to the test. The results of this test are collected in report D1.2 “Analysis of data from the first round of tests and initial development of the common scale”. Work package 2 is dealing with the pavement influence on road traffic noise emission: the main objective of this work package is to combine the existing measurement methods of SPB (ISO 11819-1) and CPX (ISO/DIS 11819-2) into a stable and reliable harmonised pavement noise emission characterisation method. The project is validating procedure incorporating correction mechanisms for temperature influence and investigating its potential use for noise calculation methods like the one proposed by the CNOSSOS-EU project. Work package 3 is dealing with rolling resistance, where the ROSANNE project is mainly building on the results obtained in the MIRIAM project and is considering standardized trailer measurements of rolling resistance coefficients of road surfaces. After a first report D3.1 “State of the art on rolling resistance measurement devices including draft standard outline” the following main report was produced “Parameters influencing rolling resistance and possible correction procedures”. In the frame of work package 4 the project is also exploring the potential for developments in the measurement of surface texture in order to find out parameters that better reflect the physical process of tyre/road interaction and that may improve the understanding of how the texture influences noise emission, skid resistance and rolling resistance. In addition to that this work package is also investigating the performance of reference tyres and pavements which are necessary for the measurement of all three road surface properties. The present paper summarizes the project status after the first 18 project months.

Footway Evaluation

Walking and cycling are green transport modes which should be given more attention in future. The quality of footways is not always very good. In most cities, road managers have difficulties in estimating the quality level of their footway network. Maintenance planning and budgeting are mostly based on ad hoc repairs.The problem is the lack of a complete evaluation method. After a market survey for different types of measurement equipment, we have combined some ideas to develop an evaluation method for footways.Our approach is based on a network analysis by the manager, with the tool described in this article. Additional information (complaints/defects) is obtained from users, through an application on their smartphones or tablets.The basic idea is that a main inspection is done by the manager at least once a year. An operator travels on a footway with a wheelchair, which is the most “sensitive” type of footway user. This wheelchair is equipped with sensors (of a smartphone) and a skid resistance measuring device. Three parameters (comfort/longitudinal unevenness in the direction of travel, gradient in the direction of travel, and crossfall) can be measured in one run, and a skid resistance measurement is made in each section of the network. In total we will thus have four technical indicators and the feedback from the user. All this information will help the road manager to maintain his footway network.We are open to refine this kind of application in consultation with the wheelchair community, using their feedback on the quality of footways. A similar exercise could be done for cycle tracks.The article will explain the idea behind the method suggested for the evaluation of footways at the network level.

Pavement Friction and Skid Resistance Measurement Methods: A Literature Review

Driving safety is of significance in the automobile industry and transportation systems. Pavement skid resistance has long been recognized as the most important parameter in reducing traffic accidents especially in wet conditions. The knowledge of the friction coefficient and skid resistance is very valuable information for safety enhancement of roads. Thus, it is important to find proper methods for measuring skid resistance and frictional properties of the pavement surface. There is a wide range of measurement methods and devices for measuring skid resistance. This paper presents a review on the research studies that have been done on characterization of the frictional properties of the pavement surface and discussed methods used for measurement and evaluation of texture characteristics and the strengths and weaknesses of these methods. Finally, some ideas have been suggested to develop new methods for better and proper measurement of skid resistance.

Measurement and evaluation of skid resistance of concrete floors

Measurement and evaluation of skid resistance of concrete floors

Towards quantification of seasonal variations in skid resistance measurements

Seasonal variation in skid resistance is a frequently reported phenomenon which has been investigated by numerous researchers. Since many variables influence skid resistance measurements, the results of such investigation do not coincide and cannot be universally applied. This study reviews the sources of seasonal variations and shows the results of a study of quantification of the effect of climatic and meteorological conditions on a section of motorway in the Madrid area and on a test track in France. A discussion is included on how recent developments may offer a way to quantify and reduce the effect of environmental conditions on skid resistance measurements and to make such measurements more stable.

A study of the laboratory polishing behavior of granite as road surfacing aggregate

Four sources of granite aggregates with different mineralogical properties were investigated. They were formed into test plates with a flat surface and polished with the Aachen Polishing Machine using quartz powder and quartz sand as the polishing agent respectively. Changes of the texture were studied on the basis of both texture measurements and skid resistance measurements measured by the Pendulum Test and the Wehner/Schulze device. By comparison of the four granites, the influence of mineral composition and crystal size on micro-texture and skid resistance changes of the aggregates is determined. The polishing and wearing resistance can be described with functions of the mineralogical parameters.

Characterization of pavement texture by means of height difference correlation and relation to wet skid resistance

Driving safety is of utmost importance in the automobile industry and is acknowledged by the introduction of the tire wet grip index as part of the EU tire label. The rubber pavement interaction is determined by the viscoelastic properties of the rubber as well as by the pavement texture. Nowadays available optical surface profiling instruments allow for a detailed measurement of surface roughness covering several length scales. This enables the validation of a mathematical statistical description of pavement texture within the framework of self-affine surfaces and hence provides a holistic characterization of surface roughness covering several length scales within a few characteristic parameters. We deduce within this article the correlation between classical surface roughness parameters and the parameter set of self-affine surfaces. These parameters allow for a detailed understanding of the relationship between pavement texture and its wet skid resistance. We present wet skid resistance measurements with the British pendulum and a linear friction tester device on different pavement textures. We demonstrate that the so-called estimated texture depth does not correlate to the surface skid resistance measured with the British pendulum. Finally, we deduce a dependency of wet skid resistance on pavement texture which is supported by current models for hysteresis friction.

Calculation of skid resistance from texture measurements

Abstract There is a wide range of routine skid resistance measurement devices on the market. All of them are measuring the friction force between a rubber wheel and the wetted road surface. Common to all of them is that they are relatively complex and costly because generally a truck carrying a large water tank is needed to wet the surface with a defined water layer. Because of the limited amount of water they can carry they are limited in range. Besides that the measurement is depending on factors like water film thickness, temperature, measurement speed, rubber aging, rubber wear and even road evenness and curviness. All of these factors will affect the skid resistance and are difficult to control. We present a concept of contactless skid resistance measurement which is based on optical texture measurement and consists of two components: measurement of the pavement texture by means of an optical measuring system and calculation of the skid resistance based on the measured texture by means of a rubber friction model. The basic assumptions underlying the theoretical approach and the model itself based on the theory of Persson are presented. The concept is applied to a laboratory device called Wehner/Schulze (W/S) machine to prove the theoretical approach. The results are very promising. A strong indication could be provided that skid resistance could be measured without contact in the future.

The Skid Resistance Evaluation on the Longterm Monitored Road Sections

Abstract The article deals with the analysis of the skid resistance results measured at the long-term monitored road sections in Slovakia in perspective of the possibility of the deterioration functions determination for the purposes of the pavement management system. There were 11 road sections evaluated, on which have been surface characteristics measured since 1998. The focus was on the evaluation of the longitudinal friction coefficient Mu measured by device Skiddometer BV11, which is the property of the Slovak Road Administration. Beside the Mu parameter, the test conditions were observed and evaluated, as well (measured speed, air and surface temperature, type of asphalts of the wearing course, traffic load, and the season (spring, autumn, respectively) in which the skid resistance measurements were performed. In conclusion, there was reviewed a presumption of the possibility to determine a deterioration functions for skid resistance in point of view the quality of the data, which have been collected on the Slovak long-term monitored road sections.

A contribution to non-contact skid resistance measurement

Over the past decades a wide range of routine measurement devices has been developed, all of them measuring the friction force between a rubber wheel and the (wetted) road surface. At the same time, many efforts have been undertaken to predict skid resistance solely from texture measurements. This paper presents a concept of contactless skid resistance measurement which is based on optical texture measurement and consists of two components: (1) measurement of the pavement texture by means of an optical measuring system and (2) calculation of skid resistance based on the measured texture by means of a rubber friction model. The basic assumptions and equations underlying the theoretical approach are presented. Two skid resistance-measuring devices were chosen to prove the theoretical approach: one laboratory device called Wehner/Schulze machine which corresponds to a locked-wheel braking test and another, the ViaFriction® device of ViaTech AS which measures the skid resistance under controlled longitudinal slip and corresponds to ABS braking conditions. The results are very promising although in the case of the ViaFriction® device only a few surfaces could be tested. A close relation between measured and predicted friction coefficients could be found. Thus, a strong indication can be provided that skid resistance could be measured without contact in the future.

Field investigation of factors affecting skid resistance variations in asphalt pavements

Pavement management activities consist mainly of three sequential yet interconnected processes: condition assessment, performance prediction and needs analysis. On this basis, knowledge of the evolution of skid resistance over time is important for pavement maintenance/rehabilitation planning. Seasonal and long term variations have a significant effect on skid resistance evolution. In the present study this effect is thoroughly investigated by modelling field data to provide a structure for the evolution of skid resistance in asphalt pavements. The considered field data includes the results of skid resistance measurements that were performed along 29 highways pavement sections of similar asphalt mix properties, with a fixed slip system (Grip Tester), over a period of four years and during different seasons. The developed model addresses that skid resistance is strongly related to the past level of surface friction, traffic, temperature and precipitation. The model was verified with a high degree of statistical certainty ensuring that mistakes have not been made in implementing the model. Furthermore, it was validated as its predictions have matched additional experimental data, with high precision (95% confidence level). This result produces evidence in support of the statement that the developed model provides accurate information about the variations of skid resistance in asphalt pavements.

Study of micro-texture and skid resistance change of granite slabs during the polishing with the Aachen Polishing Machine

In this paper, massive granite slabs were cut from lumps of rock using a diamond saw. The surface of the stone slabs was then retreated so that the slabs were characterized by different degrees of roughness. On the other hand, the slabs had no macro-texture, so that the skid resistance depended exclusively on the micro-texture. The prepared slabs were polished under various polishing conditions using the Aachen Polishing Machine. Changes of the micro-texture were studied on the basis of both texture level measured by spectral analysis and skid resistance measurements measured by the British pendulum tester. The results showed that micro-texture and skid resistance changes of the slabs are related to the applied polishing agent, initial roughness and mineralogical compositions of the granite slabs. The contribution of micro-texture to the skid resistance can be described with a function of the two texture parameters.

SEASONAL VARIATIONS IN THE SKID RESISTANCE OF PAVEMENTS IN KENTUCKY

Frequent measurements of skid resistance were made on 20 pavements in common use in Kentucky from November 1969 through 1973. Principal analysis involved relating changes in skid resistance to day of the year and relating skid resistance to temperature at the time of test, to average antecedent temperatures, and to average rainfall. Seasonal variations exhibited an annual sinusoidal cycle. The changes in sand-asphalt and bituminous concrete surfaces under high volumes of traffic were about 12 skid numbers (SNs). The changes in portland cement concrete (PCC) and bituminous concrete under low volumes of traffic were about 5 SNs. The lowest SN values occurred in early to mid-August for PCC and sand-asphalt pavements and in late August to early September for bituminous concrete. Correlations between changes in SN and temperature were best for ambient air temperature averaged over four- and eight-week periods prior to date of test. However, correlations between changes in SN and temperature were not so good as correlations between SN and day in SN and temperature were not so good as correlations between SN and day of the year. On the other hand, combining traffic volumes in the form of deviations from yearly average daily traffic with temperature yielded correlations with SN that were as good as correlations between SN and the day of the year. It was concluded that skid-resistance measurements in Kentucky should be conducted between the first of July and the middle of November to assure detection of significant differences in SN. However, frequent testing of reference sections is recommended to define more specifically each year the beginning and ending dates of the testing season. (Author)

Continuous Evaluation of the Road Skid Resistance with ViaFriction

A newly developed skid resistance measurement system ViaFriction is studied, which can detect the skid resistance under conditions with a variable slip rate, just like the braking process with an anti-lock braking system (ABS). Until now there is still no evaluation framework on the testing results from this test system. In the scope of this paper, the impact from the temperature of the ambient air, the road surface, the tire and the water for the test as well as the influence of the driving speed of the test vehicle on the testing results of the ViaFriction was identified and transferred to a correction function. This total correction algorithm for the measurement results of the ViaFriction allows a comparative analysis of the friction coefficients at different speeds and under different testing temperatures.

Evaluation of surface textures and skid resistance of pervious concrete pavement

Surface textures had long been recognized as primary factors to provide the skid resistance on pavements; however, no measurement of skid resistance on pervious concrete pavement with various surface texture parameters had been made. Fractal geometry was introduced in the present work to accurately simulate transect contour curves of pervious concrete specimens through fractal interpolation. It is proved that its fractal dimension (D) can be adopted to measure the skid resistance on pervious concrete pavement, overcoming the shortcomings of both macrotexture depth (DT) and British portable pendulum number (NBP). Combined with Fujikawa-Koike tire/road contact model, the optimization method of all surface textures was recommended for designing and constructing excellently skid-resistant and noise-absorptive pervious concrete pavement. In addition, evaluating of the abrasion process and attenuation of the surface textures on concrete pavement slabs was also the focus of this work based on accelerated abrasion test. Results show that the surface textures on pervious concrete pavement slabs is extremely durable, compared to those on conventional grooved or exposed aggregate concrete pavement slabs.

The Experience with Wehner/Schulze Procedure in the Czech Republic

The paper presents the skid resistance measurements results achieved by Wehner/Schulze method; Christian Doppler Laboratory (TU Vienna) testing device was used.The Wehner/Schulze testing device is designed to simulate the polishing action of vehicles on road surfaces.The paper shows a wide scope of W/S method usage: evaluation of polishing of different aggregate fractions, laboratory prepared test specimens and specimens cored from pavements. More testing cycles can predict the long-term development of wearing course friction coefficient.

포장노면 미끄럼 저항특성

PURPOSES : Skid resistance on pavements plays an important role in reducing the risk of vehicle skidding on wet surface particularly. Almost 9.3 percent of traffic accidents were occurred under rainy condition and these are over-represented in terms of the severity of the crashes. Recently, unusual weather conditions referred widely as the intensified rainfalls justify the need of a systematic management of skid resistance. In this context, the study carried out the observational study on the skid resistance characteristics of different types of pavement with the time passage. METHODS : This study measured the skid resistance with Pavement Friction Tester at three times within five years. The skid resistance measurement has followed the method suggested by ASTM. RESULTS : As the main results under the scope of this study, skid resistance of asphalt concrete has not nearly reduced with time. On the contrary, skid resistance of cement concrete has been rapidly reduced with time though the highest resistance was gained at the early observation. Porous asphalt concrete shows a steady decrease of skid resistance with time, anyway, the reduction rate according to the increase of measurement speeds is relatively lower than the others. CONCLUSIONS : Based on our study, skid resistance of the pavement should be regarded as one of the pavement management system, so periodic measurement should be made to assure road safety as a whole.

A Comparison Study of Friction Measurements for Chip Seal

Abstract This paper presents a development in measuring skid resistance in a laboratory performance test for chip seal. It is important to develop a relationship between the British pendulum test (BPT) and the locked-wheel skid test (LWST), or grip tester (GT). The chip seal is a typical pavement preservation treatment used by the North Carolina Dept. of Transportation (NCDOT). In North America, loss of skid resistance is a common road condition that indicates the need for a chip seal, as one of the major advantages of chip seal is an increase in skid resistance. Most agencies have a specified cycle in which skid resistance is measured as a part of their pavement-management system. These skid resistance measurements are invaluable when deciding which roads require chip seal [Gransberg, D. D. and James, D. M. B., “Chip Seal Best Practices,” NCHRP Synthesis of Highway Practice 342, Transportation Research Board of the National Academies, Washington, D.C., 2005]. In this study, skid resistance was evaluated on 14 selected chip seals using three different tests: the BPT, LWST, and GT. The correlation between British pendulum number (BPN) and skid number (SN) was relatively strong with an R2 value of 0.74. This finding indicated that the BPN measured in the laboratory could be utilized for predicting the SN, which cannot be measured in the laboratory.

Effectiveness of sodium chloride-based anti-icing filler in asphalt mixtures

The research deals with the laboratory evaluation of the effectiveness and durability of a sodium chloride-based anti-icing filler in asphaltic materials. Asphalt mastics and mixtures were prepared and tested to evaluate their de-icing and anti-icing characteristics and compared with samples containing a conventional calcareous filler. De-icing potential was measured using the ice melting capacity tests on asphalt mastics and an acceleration of the ice melting process was recorded in presence of the anti-icing filler. Similar results were determined with controlled thermal and moisture conditioning of the samples. In this case, the observed effect of the anti-icing filler was a delay of frost formation and evolution. Asphalt mixtures were also subjected to skid resistance measurements, freezing point determinations and cycles of washing and mechanical abrasion to simulate traffic and climate effects. Finally, the kinetic of sodium chloride release in water was analyzed in order to attain a preliminary evaluation of the durability of the anti-icing effects.