T. Tang
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11 records found
1
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.
Safe highway operations are one of the major concerns of pavement engineers and authorities. The reduction of skid resistance during rainy weather poses high risk for safe driving. Wet skid resistance varies under different rainfall intensities and is influenced by many factors such as permeability of asphalt material, pavement geometric design, and tire operating conditions. Empirical studies could offer useful understanding of mechanisms of wet skid resistance and its influencing factors, however, the applicability of the empirical relationships are restricted as soon as there is a change in one of the relevant factors. In recent years, the advancement of the finite element tools has enabled researchers to simulate the tire-fluid-pavement interaction in a more realistic way. However, to the best of the authors’ knowledge, the current available numerical models either do not include the real microstructures of the pavement or ignore the water infiltration through the pavement voids in the simulations. Therefore, this paper aims to providing a numerical tool to evaluate the wet skid resistance at various rainfall intensity conditions considering the effects of pavement geometric design, tire tread design and tire operating conditions. The surface characteristics and porous microstructures of the pavement are included in the model in a way that both the vertical water flow into the asphalt concrete and surface flow on the pavement can be captured in the simulation. The effects of several pronouncing influential factors as mentioned above are quantified. Such a model upon validation is expected to provide an easy and reliable tool for pavement engineers to evaluate wet skid resistance under rainy weather more accurately which can be incorporated into pavement management systems for safety highway operation.
Field calibration of Mechanistic-Empirical based models has practical limitations such as long testing times; high cost; uncontrolled environmental and traffic conditions. These factors have motivated engineers and researchers to use intermediary pavement evaluation techniques like Accelerated Pavement Testing (APT) setups that can be further classified into Linear and Circular Accelerated Pavement Testing (CAPT). In CAPT, multiple pavement segments can be simultaneously tested making it cost and time efficient. It is recommended to maintain a uniform contact force in the pavement segments to obtain unbiased testing results. For a uniform contact force, an optimal layout configuration of plates of the test track was studied using finite element analysis. The test track was divided into sixteen plates modelled using combination of four different pavement structures. The recommendations of the current study can be used to optimize the layout of the test track for CAPT with multiple pavement structures.
Any traction failure during high speed operations of automobiles may lead to fatal accidents. Therefore, it is very important to understand tire and pavement interaction. It is assumed that at high speed the hysteretic or bulk internal friction of tire predominantly accounts for tire-road friction. Hysteretic friction reflects the energy losses that occur as the rubber is alternately compressed and expanded as it slides or rolls over an irregular pavement surface texture. Inevitably, when energy dissipation takes place, temperature develops in the tire rubber. The fundamental temperature dependence of viscoelastic properties of tire rubber has a significant influence on its hysteretic friction. Nowadays, researchers have developed Finite Element (FE) and Analytical models to study the tire and pavement interaction. Several analytical and numerical models use rheological material properties to develop such models. The Dynamic Shear Rheometer (DSR) has proved to be worthy to determine the rheological properties of asphalt binders which is widely available. However, authors feel that not much attention has been paid to investigate if the DSR equipment could be used to determine rubber rheological properties. The current paper aims to present a simple procedure to test tire tread rubber by using the DSR apparatus. A complete procedure including sample preparation from the tire, their optimal dimensions of samples and their testing methodology is presented in this paper.