عنوان مقاله [English]
Existence of any liquid on asphalt pavement surface causes a decrease in skid resistance. By increasing water film and vehicle velocity, there is a moment in which hydroplaning phenomenon can occur and causes the vehicle linear speed to become disproportionate to wheel rotational speed. In this study, to understand the influence of pavement texture on the hydroplaning speed, a new lab-scale apparatus has been designed and manufactured. The lack of proportion between linear movement of vehicle shaft and the wheel rotation was found to be a good index to determine hydroplaning threshold and hence an important principle in the design of this machine. In order to evaluate this phenomenon, various types of asphalt mixtures with different aggregate grading have been made and the values of mean textures depth have been measured. Then, at various frequencies, using the manufactured device in dry and wet conditions, the surface of the pavement is subjected to hydroplaning test. Based on the measures, a simplified model was developed that is able to predict the hydroplaning speed depending on pavement’s texture characteristics and Coefficient of wheel brake. By comparing the results obtained from the proposed apparatus with the common experimental models for predicting hydroplaning speed, it has been determined that this apparatus can be used as a suitable device for investigating the effects of factors affecting this phenomenon. The results indicated that an increase of 2 and 3 times of 0.5 to 1 mm range, related to the mean texture depth of asphalt pavement, increases 8% and 17% at the hydroplaning threshold speed respectively.