EVALUATION OF PAVEMENT SYSTEMS OF THE WASHO ROAD TEST BY LAYERED SYSTEM METHODS

THE PAVEMENT SYSTEM FOR THE WASHO ROAD TEST WAS EVALUATED BY LAYERED SYSTEM METHODS. THIS INVOLVED ANALYSIS OF THE AVAILABLE DATA ON THE LOAD BEARING TESTS MADE ON THE PREPARED SUBGRADE, ON THE COMPACTED SUBBASE, AND ON THE TOP OF THE COMPLETED PAVEMENT. THE EVALUATION OF THE PREPARED SUBGRADE DISCLOSED THE UNIFORMITY AND THE RATHER HIGH DEGREE OF IMPROVEMENT ACHIEVED BY COMPACTION OF THE 2-FT SUBGRADE LAYER, AND YIELDED VALUES OF ELASTIC MODULI OF THE NATURAL SUBGRADE AND OF THE COMPACTED SUBGRADE. THE EVALUATION OF THE COMPACTED SUBBASE, VARYING IN THICKNESS FROM 0 TO 22 IN. BY STEPS OF 4 IN., WAS THEN MADE POSSIBLE BY LAYERED SYSTEM METHODS AND YIELDED SOMEWHAT SCATTERED VALUES OF THE ELASTIC MODULUS. THE VALUES CONSIDERED TO BE THE MORE REPRESENTATIVE WERE RELATIVELY HIGH. FINALLY, AN EVALUATION OF THE PAVEMENT SYSTEM AS A WHOLE YIELDED VALUES OF THE ELASTIC MODULUS FOR THE PAVEMENT LAYER OF TWO DIFFERENT TYPES ( 2-IN. AC AND 4- IN. BASE, AND 4-IN. AC AND 2-IN. BASE ), WHICH WERE QUITE HIGH. THIS EVALUATION INDICATES THE RELATIVE EXCELLENCE ACHIEVED IN THE CONSTRUCTION OF THE SUBBASE AND PAVEMENT LAYERS OF THE PAVEMENT SYSTEM. HOWEVER, THE RESULTS OF THE EVALUATION, ALTHOUGH CLEARLY INDICATING THE POTENTIALITIES AND POSSIBILITIES OF THE LAYERED SYSTEM METHOD OF ANALYSIS, WERE NOT AS CONCLUSIVE AS THEY MIGHT HAVE BEEN, BECAUSE THE DATA WERE NOT ENTIRELY CONSISTENT AND COMPARABLE, AS THEY SHOULD BE FOR SUCH EVALUATIONS. THE BASIC PROBLEM OF, AND THE ESSENTIAL NEED FOR OBTAINING FULLY CONSISTENT AND COMPARABLE DATA FOR SUCH EVALUATIONS ARE DISCUSSED. THE IMPLICATIONS AND THE POTENTIALITIES OF THIS EVALUATION ARE DISCUSSED WITH REGARD TO THE RESPONSES AND PERFORMANCES OF THE PAVEMENT SYSTEM IN THE WASHO ROAD TEST UNDER THE ACTION OF THE REPETITIVE TRAFFIC LOADINGS. /AUTHOR/