Analysis of the skid resistance and adherence between layers of asphalt concretes modified by dry way with polymeric waste

Abstract

Skid resistance is one of the most important parameters of a surface mixture due to its influence on the safety of the road. Besides, the adherence existing between the layers of a pavement makes these layers work together, which has a great impact in the useful life of the pavement. The influence on these two parameters of different polymeric waste, which have been used to modify a mixture by dry way, has been analysed. The polymeric waste added to an asphalt concrete by dry way are: polyethylene (PE) from micronized containers, polypropylene (PP) from ground caps, polystyrene (PS) from hangers and rubber from end-of-life tyres (ELT). The skid resistance and the adherence between layers of the reference and the modified asphalt concretes have been evaluated separately, so their performance can be compared. The skid resistance has been calculated with the British Pendulum Tester of the TRRL (Transport Road Research Laboratory) under two conditions: on the mixture just manufactured and on polished specimens. The adherence between layers was analysed on asphalt concretes with different texture (AC22 and AC16), applying a direct shear stress at constant speed in the joint junction (LCB shear test), and undergoing three-layer specimens to a dynamic shear stress (shear fatigue test designed by the Engineering School of Santander). The results showed that the addition of residual polymers modifies the mixtures surface properties, and the performance of the asphalt concretes changes greatly depending on the polymeric waste added.