The high-volume data collection capabilities of modern nondestructive testing equipment require an analysis method which is capable of rapid backcalculation of pavement layer moduli in a production mode of data reduction. A layered elastic analysis method named MODULUS was developed for microcomputer which is very fast in operation and provides consistently reliable results. Random errors in the measurements and systematic errors in the backcalculation process may be reduced, the former by repeating the measurements and the latter by use of a microcomputer expert system named PASELS, to provide consistently acceptable layer moduli values. Users guides to both microcomputer programs are provided. Extensive field measurements were made in different climatic zones throughout the year and were compared with laboratory measurements of the layer moduli to verify the analysis methods developed and to gauge the realism of the adjustments made from local conditions of load level, temperature, and moisture to a standard condition. Correlations between nondestructive testing devices were found to be consistent, accurate, and repeatable using layer moduli corrected to standard conditions.
Abstract