ABSTRACT
Abstract Bituminous layer moduli play a principal role in the evaluation of pavement serviceability and in the design of pavement overlay layer. These data can be measured with various laboratory and f i e l d techniques. This paper presents a theoretically rigorous approach for backcalculating bituminous layer elastic moduli from the results of non-destructive testing for measuring pavement deflection bowl under load. A FORTRAN computer program has been coded, called EPLOPT, to implement the method on a VAX computer* The author carried out an extensive programme of f i e l d deflection measurements on several parts of the highway network and performed laboratory testing and theoretical analysis to evaluate the stiffness moduli of the in-service bituminous layers. I t i s concluded that the combination of the measured deflection data using both the Deflectograph and the Falling Weight Deflectometer with the theory of Equivalent Layer Thicknesses i s much more efficient and f i e l d representative than current laboratory methods. Keywords; Flexible, Pavements, Mechanistic Design, Pavement Testing, Nondestructive Testing, Laboratory Testing, Backcalculation, Equivalent Layer Thickness, Pavement Deflections.
