Early Friction and Texture Evolution After an Asphalt Overlay

Abstract

Recent studies have shown that friction and, more notably, macrotexture reduce markedly when pavements are newly overlaid. However, past studies have not identified whether these effects are temporary and, if so, how long they may last. These effects must be quantified to inform strategies for best monitoring and managing friction and the surface characteristics of a pavement network. This paper uses a group of sites that received a surface overlay at some point between the end of 2019 and the end of 2021. At each site, friction and texture were measured sequentially after construction in the center of the lane (CL) and in the right-wheel path (RWP). These observations were used to evaluate the early friction and texture evolution after an asphalt overlay. First, seasonal effects were evaluated using the CL measurements, presumed to be unaffected by traffic, which indicated friction is affected by seasonality, whereas texture is not. A friction seasonal effect model was calibrated and then used to remove the seasonal variation from the RWP observations. The results showed that friction initially increases after an overlay but then, after reaching a maximum, starts to decrease. The average traffic volume needed to reach the point of maximum friction was 15.5 million repetitions. Four parameters, computed from the texture profile, were used to represent macrotexture. The macrotexture was found to generally increase after overlay construction, but in some sites the magnitude and number of peaks decayed with time.