Implementation of Quality Management of Base Materials with Seismic Methods

Existing practices for field quality management of unbound layers (base, subbase, and subgrade) rely on the adequacy of parameters such as density and moisture content. However, increasingly accepted mechanistic–empirical pavement design is primarily based on the strength and stiffness of the pavement layers. Therefore, methods to measure the modulus or stiffness of soil layers in the field shortly after construction may lead to a more reliable implementation of that design process. Modulus-based quality management methods may be more beneficial than traditional techniques because they test materials in their natural state. Nondestructive testing methods allow researchers to obtain modulus of pavement layers in a rapid way. Seismic methods are one example of available methods that can be used to measure the modulus of finished unbound layers. Seismic methods are particularly attractive because they yield the same parameter (low-strain modulus) for the lab and field tests and do not require any backcalculation process. Performing the simplified seismic laboratory and field tests, with more traditional tests, may lead to a smooth integration of design procedures with pavement evaluation. An overall approach that integrates design, laboratory, and field quality management processes is presented. To evaluate the proposed method, a case study was incorporated to corroborate its usefulness and convenience.