PROFILOGRAPH CORRELATION STUDY WITH PRESENT SERVICEABILITY INDEX

Several states are beginning to use roughness measurements from the Rainhart and California profilographs for construction control of rigid pavements. Texas is also considering using the profilograph for such purposes. However, the relationship between the roughness measurements provided by these devices and Present Serviceability Index (PSI), as obtained from the Surface Dynamics Profilometer (SDP), is unknown. Since the initial PSI of pavements is currently used in estimating the life of a pavement, the relationship between roughness measurements from the profilograph and PSI is needed. The other two roughness measuring devices used by the state, the Walker Self-Calibrating Roughness Device (WRD) and the Mays Ride Meter (MRM), have been correlated to PSI. A common measure of roughness, the PSI, is needed for all roughness measuring units to maintain consistent measurements. The paper provides correlations between PSI, as obtained from the SDP, and Profile Index (PI) from the California and Rainhart Profilographs. In addition to the correlations with PSI, correlations are also provided between each profilograph with one another and between roughness data from the WRD. A mathematical model of the two profilographs is provided, and the measuring capabilities of the two profilographs to various road profile frequencies or wavelength components are illustrated.