Wet handling track: Utilities, water system, coefficient of adherence

Abstract

Research and/or engineering questions/objective: A Wet Handling facility must assure a regular and controlled water film depth all along the track, homogeneity and an adequate coefficient of adherence of the asphaltic surface to allow maximum repeatability on tests. The study focused on defining the parts of the track and the construction procedures required to get the proper coefficient of adherence and to define the basis of the design of the watering system. The influence on the grip of the asphalt characteristics, the aging procedure of the track and the water treatment systems were tested and studied. The layout of the track, the design of the watering and the recovery elements (pianos, drainages, run-off areas) were done to get the safest conditions without affecting the tires and their behaviour. Methodology The Test Facilities Engineering department at IDIADA's Technical Centre has carried out a large number of studies on the asphalt characteristics to define the bituminous mixture and the grain size distribution of the aggregates to be paved in tracks with wet surfaces. The analysis of the cleaning, filtering and treatment systems for the water used in the track was done thinking on the influence of the presence of organic and non-organic particles on the grip. Based on the water study and on standard quality control tests, comparisons were made with the results obtained from other tracks. A procedure for aging the asphalt was studied and implemented for three months by means of repeated drive-through with test vehicles. The coefficient of adherence was measured every two weeks following internal braking procedure and complemented with the one indicated in the Regulation No 13 ECE. The design of the watering system took into account that the watering system needed to be adapted to the "pianos" and kerb stones to keep the desired water film depth and regularity without damaging the tires or affecting test vehicle trajectories. Results The asphalt's coefficient of adherence data obtained during the aging period and how this affects the results will be shown together with the test procedure used for the aging of the track, the basis for the design of the watering system and the water recovery system used. Limitations of this study The lack of testing regulation guidelines for these facilities gives no trustful ways to correlate the data obtained between different tracks. What does the paper offer that is new in the field? This new watering and recovering system designed and implemented gives an optimal control on the regularity of the water film depth along the track with a high percentage of water recovered on the system. Conclusions The Wet handling track utility system and pavement characteristics designed and constructed fulfil the most demanding premises in terms of water film depth regularity, coefficient of adherence of the track and water reservoir savings according to environment policies. © Springer-Verlag 2013.