Abstract of Dissertation Presented to the Graduate School
 of the University of Florida in Partial Fulfillment of the
 Requirements for the Degree of Doctor of Philosophy


 EVALUATION OF LAYER MODULI IN FLEXIBLE PAVEMENT SYSTEMS
 USING NONDESTRUCTIVE AND PENETRATION TESTING METHODS

 By

 Kwasi Badu-Tweneboah

 December 1987


Chairman: Byron E. Ruth
Major Department: Civil Engineering


 A research study was conducted to develop procedures for the eval-

uation of layer moduli in flexible pavement systems using in situ non-

destructive (NDT) and penetration tests. The Bitumen Structure Analysis

in Roads (BISAR) elastic layer computer program was used to simulate

Dynaflect and Falling Weight Deflectometer (FWD) load-deflection

response for typical flexible pavements in the state of Florida. A

field testing program consisting of Dynaflect, FWD, cone penetration,

Marchetti Dilatometer, and plate bearing tests was conducted on fifteen

pavement sections in the state of Florida. Cores of the asphalt con-

crete pavement were collected for laboratory low-temperature rheology

tests. This provided a reliable and effective method of predicting the

asphalt concrete modulus.

 A modified Dynaflect geophone configuration and simplified layer

moduli prediction equations which allow a layer-by-layer analysis of

Dynaflect deflection measurements were developed. Multiple linear