FLEXIBLE PAVEMENT MAINTENANCE REQUIREMENTS AS DETERMINED BY DEFLECTION MEASUREMENT

THIS PAPER DISCUSSES THE RESULTS OF THE USE OF THE DEFLECTION METHOD BY THE CALIFORNIA DIVISION OF HIGHWAYS FOR THE EVALUATION OF EXISTING FLEXIBLE PAVEMENTS AND THE RECOMMENDATION OF SUITABLE RECONSTRUCTION. SINCE 1960, SOME 80 PROJECTS INCLUDING STATE HIGHWAYS, COUNTY ROADS, AND CITY STREETS, HAVE BEEN SUBJECT TO DEFLECTION INVESTIGATION BY THE MATERIALS AND RESEARCH DEPARTMENT OF THE CALIFORNIA DIVISION OF HIGHWAYS. THE PRIMARY PURPOSE OF THESE INVESTIGATIONS WAS THE RECOMMENDATION OF APPROPRIATE CORRECTIVE TREATMENT. AS A RESULT OF THIS INTENSIVE PROGRAM, A LARGE VOLUME OF DATA ON THE DEFLECTION ATTENUATION PROPERTIES OF VARIOUS ROADWAY MATERIALS HAS BEEN ACCUMULATED AND IS PRESENTED IN THIS REPORT, ALONG WITH THE RESULTS OF INDIVIDUAL DEFLECTION STUDIES. THE TEST PROCEDURE, METHOD OF EVALUATION OF DEFLECTION DATA, AND DESIGN CRITERIA WHICH HAVE EVOLVED ARE EXAMINED IN DETAIL. IN ADDITION, ECONOMICAL AND PRACTICAL FACTORS INVOLVED IN MAKING A SPECIFIC RECOMMENDATION ARE DISCUSSED. A SEPARATE SECTION OF THE REPORT IS DEVOTED TO A REVIEW OF CURRENT DEFLECTION RESEARCH, INCLUDING WORK NOW BEING DONE ON THE ESTABLISHMENT OF MAXIMUM DEFLECTION CRITERIA WHICH MAY BE ADJUSTED FOR VARIATIONS IN TRAFFIC VOLUME. A BRIEF ANALYSIS OF RADIUS OF CURVATURE DATA OBTAINED WITH THE DEHLEN CURVATURE METER IS ALSO INCLUDED. /AUTHOR/