Realistic pavement serviceability equations using the 690d surface dynamics profilometer

The importance of pavement roughness as the major input to the serviceability of pavements has been previously demonstrated. This research study is related to the Serviceability-Performance (S-P) concept that was developed at the AASHO Road Test by Carey and Irick. The study was conducted in two phases, the screening experiments and the main rating sessions. Two types of variables were identified for study, one associated with the rating process and the other related to pavement characteristics. Experiments were designed for both the screening and the main rating session. Rating panels were appropriately constituted to evaluate the riding quality of selected sections of pavement. For the main rating sessions, the rated sections were profiled using the new Model 690D Surface Dynamics Profilometer (SDP). From the profile data, a family of profile summary statistics called Root-Mean-Square Vertical Accelerations (RMSVAs) were computed. A calibrated Maysmeter and Walker accelerometer device (SIometer) was also operated on these sections. Rigorous statistical techniques were used to analyze the data. Analyses of variance revealed the significant effects of the rater variables and the pavement variables studied. A multiple linear regression procedure was used to develop reliable serviceability equations (with good predictive capabilities) by regressing the mean panel ratings on the set of RMSVA indices. Correlation analysis of the Maysmeter and SIometer measurements with the panel ratings showed that the calibrated Maysmeter predicts panel ratings better than the SIometer. The best prediction of the panel ratings, however, is achieved by the 690D profilometer. (Author)