This paper deals with experience acquired in Argentina in nondestructive testing of pavements and back calculation of moduli from 1967 to 1987 by the research group of the IMAE (Institute of Applied Mechanics and Structures). National University of Rosario.

The paper addresses three fundamental areas of engineering research concerning nondestructive testing (NDT): 1. The in situ measurement of material strengths using various NDT devices. 2. The measurement of resilient modulus of soils and granular materials, and dynamic moduli of bound surface materials. 3. Back calculation of moduli using various analytical models on microcomputers.

In situ nondestructive testing measurements have included surface wave propagation methods, the Lacroix deflectograph, and a specially fabricated double Benkelman beam which allows the easy calculation of the deflection basin. These measurements have been made on many different types of cross-sections over numerous roadbed soils.

Nondestructive laboratory measurements to determine the material strengths have included: ultrasonic pulse, resonance method, resilient moduli by dynamic compression and triaxial test, and dynamic moduli by indirect tension testing.

Development efforts have focused on modifying and adapting the ALIZE III elastic-layered program developed by Laboratoire Central des Ponts et Chaussées (LCPC) in France for local conditions in Argentina.

Modifications have been made for the unique local soils, climate, and traffic patterns. The program has been adapted for use on handheld notebook microcomputers.