Texture and skid resistance of asphalt mixtures with crumb rubber: laboratory assessment

The skid resistance of asphalt pavements is related to pavement texture. Also, the addition of crumb rubber (CR) from end-of-life tires could improve friction, although this aspect of CR pavements has not been sufficiently studied. In this study, three types of mixtures were produced, a semi-dense mixture AC, a stone matrix asphalt SMA mixture, and an open-graded mixture BBTM. Each one was tested with three percentages of CR: 0.0, 0.75, and 1.50%. The surface of these mixtures was worn and polished in successive stages. At each stage, the macrotexture and microtexture data were obtained using a laser texturometer, and the skid resistance was measured using the British Pendulum Test (BPT). From these data, prediction models for the British Pendulum Number (BPN) value were adjusted based on macrotexture, microtexture, and CR content. According to these models, the microtexture of the pavement influences the BPN value more than the macrotexture for all types of mixtures studied. In addition, CR explains part of the BPN value of skid resistance in the SMA mixture and in the open-graded BBTM mixture. As for the semi-dense mixture, the presence of CR does not seem to significantly influence the skid resistance.