Field and Loading Unit Analysis of Vertical Pressure Distribution on Highway Sublayers

Abstract

Traffic loads on pavements transfer to base, subbase and subgrade levels.These over loads on sublayers cause severe deterioration to the pavement and thusdiminish its life. Through using geogrids interface between base and subbase, transferredload efficiency can be reduced. Related to load transfer mechanism, sublayer thickness,design and aggregate gradation distribution are so crucial. In this study, vertical pressuredistribution analyses according to traffic loads, tire configuration and layer thickness wereinvestigated with field and laboratory test. Measurement sensors were settled on asphaltpavement and embedded base layer, obtained data were saved. The pressure valuesranged from 550 kPa to 790 kPa on top of the pavement surface and from 31 to 33 kPa ontop of the subbase layer were obtained. In each test, 35 kPa vertical pressure and ESAL’sof 80 kN were applied by the vertical piston in accordance to the field. 2 types of geogridswere used for laboratory analyses; each geogrid type function related to vertical pressuredistribution on itself were calculated. Cumulative distribution function was used forestimating the probability of damage risk. The function parameters calculated with thehelp of lognormal mean and lognormal standard deviation values of highway verticaldisplacements. The cumulative distribution functions were generalized and the probabilityof the damage was shown on graphics. With the results of this study; damage probabilitycan be estimated for any highway reinforced with geogrid Hexagonal shape andCrosswise shape.