Comparisons between New and Traditional NDT Devices and Control Methods for Construction Quality of Highway Subgrade

Subgrade is the base of highway structures, so to evaluate its construction quality accurately is very important to ensure the required strength of the whole highway. Several subgrade segments under construction of Tai-Ao highway in China were selected as engineering examples, the point-to-point test mode was adopted, and then the deflections, dielectric values and compaction degrees were in-situ tested with the new and traditional NDT (Non-destructive testing) devices or control methods such as FWD (dynamic falling weight deflectometer), BB (static Benkenlman beam), PFWD (portable falling weight deflectometer), GPR (ground penetrating radar), special dielectric constant device, and sand cone method, and FWD, PFWD and GPR are proved to be the rapid and precise devices for quality control of the highway subgrade.