Coaxial transmission lines: Development of test procedures for concrete

The use of ground-penetrating radar as a nondestructive investigative techn ique has gained increasing acceptance both in the United States and in Euro pe for assessing the structural integrity of concrete structures. However, without an accurate knowledge of the electrical properties of concrete at r adar frequencies, it is difficult to quantitatively assess the results of a ground-penetrating radar survey. This paper reports the simultaneous, but independent, developments of two coaxial transmission line systems at Virgi nia Tech and The University of Liverpool. Both are designed to measure the relative permittivity and conductivity of concrete over a range of frequenc ies from 100 MHz to 1 GHz. This paper discusses the development of the two transmission Lines, and a comparison of the two methods of measurement and interpretation of results.