This report discusses possibilities of using radar technology in asphalt pavement investigations in several types of pavement. The main focus is on highly porous asphalt (OSA) and watertight asphalt concrete (WAB), as used in Dutch seawalls. The determinations of layer thickness as well as layer integrity are important goals. The asphalt pavements as discussed are used on seawalls and therefore saline environments receive special attention as they affect the penetration depth most. References given come from the public domain, no attempt has been made to access private domain publications. Several internet addresses of companies in the private domain are listed at the end.