Abstract
The structural testing of existing pavement and overlay design using conventional sampling and laboratory testing is not only expensive and time consuming, but also a difficult task. In contrast, nondestructive testing (NOT) using equipment such as portable dynamic cone penetrometers (DCPs), falling weight deflectometers and defectographs can be used to investigate the structural capacity of the different layer materials and for the design and rehabilitation strategies for the pavement. Consequently, an extensive NDT program was carried out in the U.K. and Pakistan on unbound granular material using DCP. This paper presents an empirical relationship between DCPs and California bearing ratio (CBR) testing for road-base/sub-base materials. Using this relationship, the CBR values can be calculated using the knowledge of the layer strength of materials based on its DCP values.