Friction is one of the essential aspects of pavement performance and safety. Unfortunately, the rate at which the friction data are being collected exceeds the rate at which the data can be proficiently analyzed. Furthermore, the Utah Department of Transportation (UDOT) lacks long-term trend analysis for the many years of locked-wheel skid trailer (LWST) data collected in Utah. In addition, UDOT is missing a statistically adequate correlation equation between friction-testing devices. Likewise, only one method is used in Utah to prequalify aggregates for use in pavements. Finally, there has not been an investigation of the potential use of lithium silicate solution in Utah as a hardening agent to decrease the rate of friction loss. This research consists of five objectives. The first objective was to investigate pavement friction factors that influence skid resistance; methods of measuring skid resistance in the laboratory and the field, including correlations between test results; methods of evaluating aggregate sources; and methods of enhancing skid resistance of asphalt pavements through a comprehensive literature review on these subjects. The second objective was to investigate temporal trends in skid numbers measured using the LWST on Utah highways with different surface treatment types. The third objective was to develop a three-way correlation between the skid number measured with the LWST in the field, the British pendulum number measured with the British pendulum tester (BPT) in the field, and the polish value measured with the BPT in the laboratory. The fourth objective was to investigate selected performance-related properties of aggregates used to produce surface treatments at several field sites representing Utah conditions. The fifth objective was to examine the potential benefits of lithium silicate treatment for improving the resistance of aggregates to polishing. The scope of the research for the five objectives included statistical analysis, field testing, and laboratory experimentation. The findings include, first, a literature review that identified four critical deficiencies in Utah’s friction-related literature, which formed the basis of the remaining four objectives. Second, a statistical analysis of 9 years of LWST data indicated above-average skid values across Utah’s pavement network. Third, correlations were evaluated for multiple friction-testing devices. Fourth, X-ray diffraction testing methods were found to compare favorably to the accelerated polish test. Fifth and finally, the effects of lithium silicate solution on polish-susceptible aggregates were documented. This research has substantially advanced the body of knowledge on pavement friction testing and improving the resistance of aggregates to polishing in Utah through laboratory and field experimentation





Date Submitted


Document Type





aggregate polishing, British pendulum tester, circular texture meter, dynamic friction tester, lithium silicate, locked-wheel skid trailer, pavement friction, skid number



Included in

Engineering Commons