Characterization of Microtexture on Typical Pavement Surfaces: A Pilot Study

The Indiana Department of Transportation has conducted annual network inventory friction testing using the locked wheel trailer to reduce wet pavement crashes. However, issues have arisen concerning the data credibility and field operation safety on high-speed highway facilities. Some researchers have investigated the evaluation of pavement friction using macrotexture measurements and found the relationship between friction and macrotexture is extremely weak. Textures that affect friction include both macrotexture and microtexture. Currently, macrotexture can be readily measured at highway speeds, but microtexture is evaluated by the friction from a surrogate device at low speeds. Microtexture depends mainly on the surface properties of the aggregates and plays an important role in friction force. The evaluation of pavement friction from texture measurements will be undermined without considering microtexture. A pilot study was conducted by the authors to examine the use of laser-based sensors in measuring pavement microtexture. The requirement of frequency was established for choosing lasers. Microtexture testing was conducted on core samples. The data was filtered to produce microtexture profiles. The mean profile depth (MPD) together with slope variance (SV), and root mean square (RMS) varies with the baseline length. The results indicate that SV and RMS can produce useful information for evaluating pavement friction.