Some longstanding problems in geotechnical laboratory testing of pavement and roadbed materials

Abstract

In spite of most of our laboratory test methods having been used for over 70 years some of them remain problematic either in terms of the choice of the method and apparatus or its reproducibility, or both. Those methods discussed are road vs foundation indicators, their origin and when each should be used, the problem of accurately determining the mica and smectite contents of pavement materials, the necessity for using several test methods for aggregate durability and, in all cases, the necessity for using the same or comparable methods to those used to derive the specifications, especially for soluble salts and pH. The problem of stabilization durability is briefly discussed ‒ is it still a problem or just the interpretation of the test results?