Enhancing pavement surface macrotexture characterization by using the effective area for water evacuation

Adequate macrotexture characterization is an essential objective for transportation practitioners because primary pavement surface characteristics like friction, tire-pavement noise, splash and spray, and rolling resistance are significantly influenced by pavement macrotexture. This paper proposes an enhanced macrotexture characterization index based on the effective area for water evacuation (EAWE) that better estimates the potential of the pavement to drain water and provides improved correlations with two properties of pavement surfaces that are predominantly affected by macrotexture: friction and noise. A three-step methodology is proposed to compute the index: (a) a spikeremoval procedure that assures the reliability of the texture profile data; (b) an enveloping profile calculation, which is necessary to delimit the area between the tire and the pavement when contact occurs; and (c) a definition of the EAWE, which serves as the index for characterizing macrotexture. Comparisons of current mean profile depth (MPD) and proposed EAWE macrotexture indexes by using 32 pavement sections confirmed that MPD overestimated the effective area for water evacuation between a tire and the pavement surface. Correlations for MPD and EAWE indexes with tire-pavement friction and noise were performed, and measurable improvements in correlations were achieved. Results show that it is possible to define a promising index on the basis of the EAWE that realizes advantages over MPD.