PAVEMENT PERFORMANCE ASSESSED BY DEFLECTION

PAVEMENT DEFLECTION TESTS WERE MADE ON THE SHELL AVENUE ASPHALT TEST ROAD WITH THE CALIFORNIA DIVISION OF HIGHWAYS TRAVELLING DEFLECTOMETER. THIS EQUIPMENT MEASURES SURFACE DEFLECTIONS UNDER A 15,000-POUND SINGLE AXLE LOAD AND PROVIDES AN ANALOG TRACE OF A THE DEFLECTED BASIN ALONG THE LONGITUDINAL AXIS. DEFLECTION MEASUREMENTS WERE MADE AT THE SAME NOMINAL POINTS WITH EACH SUCCESSIVE STUDY. DEFLECTION STUDIES AND CONDITION SURVEYS WERE MADE SHORTLY AFTER THE PAVEMENT WAS PLACED. NO DISTRESS WAS FOUND AT THAT TIME. A DEFLECTION STUDY AND CONDITION SURVEY WAS MADE IN 1962, NEARLY A YEAR AFTER THE PAVING, WAS USED IN THIS ANALYSIS. FIGURES SHOW THE DEFLECTION RESULTS AT THE DIFFERENT TEST TIMES. ONE FIGURE COMPARES THE DEFLECTION RATE IN 1962 TO 1968. AT THIS POINT, THE ROAD HAS EXPERIENCED A SERIOUS DEGREE OF DISTRESS AND REQUIRES MAINTENANCE. IT WAS INTERESTING TO FIND THAT SMALL DIFFERENCES IN DEFLECTION CAN RESULT IN A SLIGHT RANGE OF DISTRESS.